lmlmf'"will 32.} stinger: 6State 1 University This is to certify that the dissertation entitled Effect of Site on Growth of Hybrid Poplar Clones Planted on a Commercial Scale presented by Ruth Fortune Woods has been accepted towards fulfillment of the requirements for Ph.D. Forestry degree in Major professor Datew . , . . .- .n MSU-U'" ‘_”‘ ' 1 rr 042771 MSU LIBRARIES RETURNING MATERIALS: Place in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date stamped below. 200 A287 EFFECT OF SITE ON GROWTH OF HXBRID POPLAR CLONES PLANTED ON A COMMERCIAL SCALE By Ruth Fortune Woods A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements ‘ for the degree of DOCTOR OF PHILOSOPHY Department of Forestry 198% \, X . In .1“ r" . ~.e / 367/ ABSTRACT EFFECT OF SITE ON GROWTH OF HYBRID POPLAR CLONES PLANTED ON A COMMERCIAL SCALE By Ruth Fortune Woods Two-, four- and five-year height growth of Populus hybrids were measured over a full range of USDA Soil Conservation Service natural and altered soil drainage and texture classes on fields planted by Packaging Corporation of America using intensive culture. Five clonal trials with 40 clones each were examined for 4-year height growth and were analyzed for effects of site, clone and site by clone interaction. Substantial soil variability became an important factor on the previously-planted sites and had to be considered in the statistical analysis. Ten clones with the best 4-year height growth were identified. Four- and five-year height growth of several of the most promising clones from the clonal trials were then examined over a range of soil/site conditions in commercial-size plantations using a tillage plus herbicide management system. Two-year growth was evaluated using a no-till system. Height growth under both management systems significantly decreased on sites other than those with the most optimum conditions for agricultural crops. Using the results from the clonal trials and the two tillage system studies, soil/site factors which affected establishment and early growth of hybrid poplar plantings were summarized and outlined in detail, and a practical field guide was formulated for evaluating the potential of agricultural fields for the intensive culture of hybrid poplars. DEDICATION This dissertation is lovingly dedicated to my father, Walter H. Fortune, who aided in the germination of and then nourished my love for soil and plants at a very early age. His love for horticulture and his unselfish wish that I might accomplish in my lifetime what he did not have the opportunity to do in his, has been my driving force for my B.S., M.S. and Ph.D in Forestry. No father could have been more encouraging and supportive, particularly during the last hectic year of study and through the writing of this dissertation. His time and effort spent so lovingly during his present retirement is deeply appreciated. ii ACKNOWLEDGMENTS I wish to thank my major professor, Dr. Donald I. Dickmann, for providing the opportunity for this research topic and, ultimately, the Ph.D degree. His guidance, financial aid, professional and moral sup- port and, particularly in the last year, his warm and sincere friendship is deeply appreciated. May whatever work I do in the future be worthy of his unfailing confidence and encouragement. I must also thank my employer in the field, Mr. Robert F. Davis, who provided the opportunity for field research while I was on leave from the university. His support, guidance and friendship far surpassed that of any person I have ever worked for. Dr. Louis F. Wilson deserves my sincere thanks for making the first summer of research possible and for crucial encoura- gement and friendship at just the right time. Dr. James W. Hanover was highly instrumental in bringing me to Michigan State Univerisity, initially, and provided guidance and encouragement throughout the study. Dr. James B. Hart shares my love for soils and provided the necessary field tools as well as guidance with the dissertation. I am sincerely grateful to both Drs. Hanover and Hart. My dear friend Pat Pedersen deserves tremendous credit for the beautiful graphics work plus love, support and encouragement. To my fellow graduate students and depart- ment office personnel I offer my sincere thanks. To my highly supportive family I offer my love and appreciation. iii TABLE OF CONTENTS LIST OF TABLES I I I I I I I I I I I I I I I I I I I I I I LIST OF FIWRES I I I I I I I I I I I I I I I I I I I I I DI'I‘RODUCT'ION I I I I I I I I I I I I I I I I I I I I I I I CHAPTER I. Performance of 40 Hybrid Poplar Clones Over a Range of Natural Soil Drainage and Texture Conditions ‘ IntrOdUCtion o o o o o nethOdS o o o o o o o 0 Results and Discussion conClUSiOnS o o o o o 0 References 0 o I o o 0 CHAPTER II. Effect of Height and Diameter Growth on Three Hybrid Poplar Clones Under Intensive Culture . . . . . IntrOdUCtiOn o o o o o o o MethOdS o o o o o o o o o a Results and Discussion . . COnC1USiOn-S o o o o o o e 0 References 0 o o o o o o 0 CHAPTER III. Two-year Height Growth of Three Hybrid Poplar Clones Using No-till Culture on Old Farm Fields . . . Introduction . . . . . Method-$0000.00. Results and Discussion Conclusions . . . . . . References . . . . . . CHAPTER IV. Site Evaluation Procedures For Intensive Culture of Hybrid Poplar on Old Fields . . . . . . . . IntrOdUCtiOn o o o o o o o o o o c o o o o o o o Soil/site Factors Affecting Hybrid Poplar Culture Field Evaluation Guide For'Hybrid Poplar . . . . COnCIuSions I I I I I I I I I I I I I I I I I I I Reference 8 I I I I I I I I I I I I I I I I I I I iv Page vii 13 25 27 28 29 32 #8 52 55 58 72 76 77 78 92 93 LIST OF TABLES Table 3. 9. 10. CHAPTER I Physical and chemical site factors affecting 4-year height grOWth Of “0 hybrid poplar Clones o o o o o o I o o e o o o Forty hybrid poplar clones planted by PCA in clonal trials in 1979 over five SCS soil texture and natural soil drainage Classes. 0 o o o o o o I o o o o o e o o o o o o 9 Ranking of 4-year average height growth (m) and survival (%0 of #0 hybrid poplar clones on 5 sites representing a range of SCS soil texture and natural soil drainage CJaSSeSI I I I I I I I I I I I I I I I I I I I I I I I I I Two-way analysis of variance showing effects of site, clone and site by clone interaction on heyear height growth of hytrid poplar clones in clonal trials over five soil/site conditions. 0 o o o o o o o o o o o o o o o o o o o o o o 0 Percentage change in 4-year height growth of’hybrid poplar clones when planted on sites other than Site 2, which represented the best in this study. . . . . . . . . . . . . Fom-year height growth of the 10 tallest hybrid poplar clones on the three most productive sites in this study. . CHAPTER II Physical site factors affecting hybrid poplar height grow-thI I I I I I I I I I I I I I I I I I I I I I I I I I I Description of 4- and 5-year mean height and diameter growth of 3 hybrid poplar clones on nine research sites. . CHAPTER III Soil/site factors affecting 1- and 2-year height growth of hytrid poplar cultivars NE 19 and DN 34. . . . . . . . . Soil/site factors affecting 1- and 2-year height growth of hybrid poplar cultivar Raverdeau on 6 sub-sites in Sherman Township, Section 10 (Sherman 10), with altered $011 drainage (ASD)0 o o o o o o o o o o o o o o o o e o o Page 10 11 18 16 19 22 33 6O 67 LIST OF TABLES Table Page CHAPTER IV 11. Site factors which make up NATURAL SOIL DRAINAGE, the most important consideration in selecting a site for intensive culture of hybrid poplar in Lower Michigan. . . . . . . . . 80 12. Physical soil factors that contribute to EFFECTIVE GROWING SPACE for hybrid poplars in Lower Michigan. . . . . . . . . 83 13. SITE HISTORY AND POTENTIAL MANAGEMENT CONCERNS that affect productivity potential of hybrid poplar under intensive clfl-tm I I I I I I I I I I I I I I I I I I I I I I I I I I % LIST OF FIGURES Figure Page 1. 3. 5. 7. CHAPTER I A: Soil variation on original Clonal Trial-3 in Riverton Township, Section 13 of Mason County. Only Soil 3 (Site 3) was used in this study. B: Soil variation on original Clonal Trial-h in Riverton Township, Section 23 of Mason County. Only Soil 7 (Site h) was used in this study. Wildfire eliminated the trees on Soil 8. C: Soil varia- tion on original Clonal Trial-2 in Logan Township, Section 24 of Mason County. Only Soil (Site 2) was used in this study. Sites 1 and 5 had homogeneous soil conditions throughout the three replications. . o o o a a o o o o o o 9 Influence of natural soil drainage and soil texture on average 4-year height growth of 40 poplar clones. Sites 1 and 5 are not significantly different from each other. All other comparisons are significantly different at onIOJ-I I I I I I I I I I I I I I I I I I I I I I I I I I 17 Four-year height growth of four fast-growing P. x euramericana hybrid poplar clones with strongly exacting site requirements. Site 2, although marginal, had the best conditions in the study. . . . . . . . . . . . . . . 24 CHAPTER II Influence of natural soil drainage and soil texture on height growth of three hybrid poplar clones on nine researCh sites. 0 o o o o o o o o o o o o o o o o o e o o 35 Percentage of total trees per clone sampled on eight research sites infected with a major pathogen or insect pest in August, 1982. Field evaluation assisted by the North Central Forest Experiment Station and Iowa State University, Department of Forestry; data prepared by the author I I I I I I I I I I I I I I I I I I I I I I I I I I 49 CHAPTER III Influence of natural soil drainage and soil texture on layear (cross-hatched bar) and 2dyear (black bar) height growth of hybrid poplar cultivars NE 19 (A) and DN 34 (B). Bars not sharing a common lower case letter are signifi- cantly different (P:_'_0.0l) for 2-year growth. . . . . . . . 59 Influence of soil texture and altered soil drainage on l-year (cross-hatched bars) and 2-year height (black bars) of hybrid poplar cultivar Raverdeau. Bars not sharing a common lower case letter are significantly different from each other (P:0.0§) for 2-year growth. . . 69 vii LIST OF FIGURES Figm‘e CHAPTERIV 8. Field guide for evaluating the potential of agricultural fields for intensive culture of hybrid poplars. . . . . . . viii Page 90 INTRODUCTION Research involving the intensive culture of Populus hybrids has steadily increased since Ernst Schreiner described European poplar timber production and identified its potential application of such to the United States (Schreiner 1959). He laid the groundwork for genetic improvement of the genus through hybridization and establishment of field trials, and he outlined the following objectives which were adopted in many later studies: (1) create poplar hybrids for use over a wide geographic range and a variety of site conditions, (2) select clones with rapid early growth and the potential to sustain such growth over a short rotation, (3) identify clones showing field resistance to pests, (h) classify poplars by growth habit and timber form and (5) maintain genetic control of clones with desirable characteristics through clonal propagation (Schreiner 1974). Interest in and enthusiasm for wide-ranging field Populus trials caught on, particularly throughout the central and northeastern United States and Canada. Muhle-Larsen (1979) identified the diminishing availability of good agricultural land which would allow hybrid poplars to reach optimum production. He encouraged extensive plantings on more plentiful lower productivity sites, thereby contributing to greater total production potential. Anderson (1980) identified one million idle farm acres in Eastern Ontario, that if planted to hybrid poplar could potentially produce large quantities of biomass with known and predictable characters in a very short time. Zsuffa (1979) identified serious regional hardwood deficiencies in southeast Ontario, and 1 2 initiated industrial, short-rotation field trials leading to the selection of improved poplar stock with recognized genetic characters and quality. The U.S.D.A. Forest Service, Forestry Sciences Laboratory in Rhinelander, Wisconsin, began research on intensive culture of hytrid poplar in 1970. Efforts were accelerated in the area of plantation establishment and management with receipt of additional funding from the Department of Energy (DOE) in 1977. Field studies were established at Pennsylvania State University in the early 1970's which concentrated on growth and yield of selected poplar clones (Bowersox & Ward 1976) and included investigations into soil fertility and nutrient needs of hybrid poplar in plantation culture (Bowersox & Ward 1977). The Michigan State Cooperative Iree Improvement Program (MICHCOTIP) ran preliminary field tests of hybrid poplars prior to 1978 (Brissett gt a; 1979). When grant monies were allocated by DOE in 1978, clonal eval- uation trials were established in several locations in Michigan. Packaging Corporation of America (PCA) , with a corrugated medium pulp and paperboard mill at Filer City, Michigan, began planting Populus hybrids in two counties within 28 km of the mill in 1969. Clonal trials with “0 hybrids were established across a wide spectrum of soil types and soil drainage classes. Considerable clonal, site preparation, and insect and disease monitoring was conducted but personnel to analyze and report on the findings were lacking. With the receipt of DOE funding in fall of 1980, a comprehensive investigation was initiated on the effects of site factors on height growth of hybrid poplar under intensive culture over a wide range of site conditions. This dissertation presents the results of that investigation. The objectives of this research were: 1. 3. Evaluation of 4-year height growth of 40 hybrid poplar clones planted on marginal farm fields with five different soil texture and natural soil drainage conditions. Determination of 4- and 5-year height growth of three hybrid poplar clones planted over nine different soil/ site conditions under a tillage plus herbicide culture. Determination of 2-year height growth of three hybrid poplar clones grown under a no-till culture over a range of soil textures with both natural and altered soil drainage. Formulation of a practical site evaluation procedure for the intensive culture of hybrid poplars on marginal farm fields using 4-year height growth, soil/site data and vegetation analysis obtained from the nine sites identified in Objective 2. REFERENCES Anderson, H.W. 1980. Intensive management of hybrid Populus. 1980. Forestry Chronicle. 59:171-173. Bowersox, T. W. and W. W. ward.. 1977. Soil fertility, growth and yield of young hybrid poplar plantations in Central Pennsylvania. For. Sci. 23. 463-467. Bowersox, T.W. and W.W. Ward. 1976. Growth and yield of close-spaced young hybrid poplars. For. Sci. 22:449-454. Brissett, J.C., J.W. Hanover, T.J. Stadt & J.W. Hart. 1979. Improved poplars for Michigan through the Michigan State Cooperative Tree Improvement Program. In: Proc. North Am. Poplar Council, 1979, Annual Meeting, Thompsonville, MI. P. 115-122. Muhle-Larsen, C. 1970. Recent advances in poplar breeding. Intern. Rev. For. Res. 3:1-67. Schreiner, E.J. 1959. Production of poplar timber in Europe and its significance and application in the United States. U.S. For. Serv. Agr. Handbook, No. 150. 124 p. Schreiner, E.J. 1974. Poplars can be bred to order for mini-rotation fiber, timber and veneer production and for amenity plantings. In: Proc. let Northeastern Forest Tree Improvement Conference 213 85-96 0 Zsuffa, L. 1979. The breeding of Populus species in Ontario. In: Proc. Tree Improv. Symp. Canadian-Ontario Joint For. Res. Comm. Symp. PrOCo 0-P-7’ 19790 P0 153-1590 CHAPTER I PERFORMANCE OF 40 HYBRID POPLAR CLONES OVER A RANGE OF NATURAL SOIL DRAINAGE AND TEXTURE CONDITIONS INTRODUCTION Hyirid poplar clonal trials were established in 1979 by Packaging Corporation of America (PCA) near Manistee in the Lower peninsula of Michigan. Sixty cultivars were obtained from nurseries in Ohio, Pennsylvania, Wisconsin and Ontario to test for rapid early growth, growth habit and field resistance to pests over a variety of soil/site conditions. This last objective was particularly important because PCA planned to utilize nearly 1620 ha of corporation-owned marginal agri- cultural land for hybrid poplar intensive culture production plantings. The decision to establish the clonal trials on a full range of soil/site conditions was reinforced by results presented in the liter- ature about on-going clonal trials in the Northeastern United States. Schreiner (1974) stressed the need for poplar clonal tests over a variety of Site conditions. Wendel (1972), who tested 50 of Schreiner's (Northeastern) clones on one West Virginia bottomland site, warned that similiar growth could only be expected on a site with the same soil/ site conditions. Brissett et a1 (1979) reported on clonal trials established in both the lower and upper peninsulas of Michigan, and stressed the importance of field testing clonal material at several locations with various soil types and climatic conditions. Demeritt (1981a), reporting on 50 years of hybrid poplar research, concluded that we still need to determine which clones will do best on a particular site and that caution must be used in extrapolating results due to 8011/ site interaction of clones. Evidence shows only a few clones will do well at more than one location (Demeritt 1981b). Zsuffa (1979) has 7 established short-rotation field trials over a wide range of soil/Site conditions in eastern Ontario, and Barkley §t_al (1983) reported on clonal performance on some of the Ontario Sites. They stressed the importance of establishing both production plantings and clonal trials in the same area and over a variety of site conditions. PCA clonal trials were planted on five former agricultural fields that encompass a range of soil/site conditions. No field soil eval- uation was made prior to initial establishment, however, and current USDA Soil Conservation Service (SCS) soil surveys were not available for soil series identification. General field observations of surface soil texture and soil moisture conditions indicated a range of sandy to clayey textures combined with dry, moderate or wet conditions. The objective of this study was to evaluate 4-year height growth of the five hybrid poplar clonal trials on areas of 52232: homogeneous soil/site conditions having enough replication for statistical analysis. Using these guidelines, 40 clones occurring on five homogeneous sites were ranked for performance by site and analyzed for clone/Site inter- action and significant differences in height growth within and between sites. METHODS Soil mapping of each of the 0.4 ha clonal trials was done using a bucket auger along transects every 20 m. One soil pit was dug on each separate soil condition and soil profiles were described, tent- atively placing each soil in one of the SCS soil series. Natural soil drainage was identified using SCS criteria for placing soils in soil management groups. These criteria are based on depth of mottles from 8 the soil surface, color of mottles, gleying of base soil color and depth to impervious clay layers or cemented hardpanso Soil samples taken from each horizon were analyzed for percentage sand, silt and clay at the Michigan State University (MSU) Soil Test Laboratory; this analysis confirmed dominant soil texture and SCS soil series. Composite soil samples were taken from the Ap (surface horizon or plow layer) and analyzed at the MSU Soil Test Laboratory for pH, P, K, Ca, Mg and percent organic matter. Using a double cylinder hammer-driven core sampler, soil samples were taken at 20, 40 and 60 cm from the surface, dried at 105°C to a constant weight, and dry bulk density determined for each site. The clonal trials were originally planted in a randomized block design with 5-tree row plots of each clone in three replications. After substantial variability was identified by soil mapping, six homogeneous. areas were chosen that contained from one to three replications of a majority of the 60 clones (Figure 1). During the 1981 growing season, however, a wildfire ignited by an electric fence in dry grass burned off over half the trees on one of the six sites; that site was then eliminated. Five sites are used in this study, representing a range in SCS soil texture, natural soil drainage classes and SCS soil series (Table l). Forty of the 60 originally-planted clones are included in this data set (Table 2), with from one to fifteen observations per clone per site. Height growth and survival from 1979, the year of establishment, through 1981 for all trees on each site (100% sample) were measured by PCA. This information was available for use in this study, as was 4-year height growth and survival measured between November, 1982 and February, 1983. Clones were ranked from tallest to shortest on each site. Figure l. A: Soil variation on original Clonal Trial-3 in Riverton Township, Section 13 of Mason County. Only Soil 3 (Site 3) was used in this study. B: Soil variation on original Clonal Trial-4 in Riverton Township, Section 23 of Mason County. Only Soil 7 (Site 4) was used in this study. Wildfire eliminated the trees on Soil 8. C: Soil variation on original Clonal Trial-2 in Logan Township, Section 24 of Mason County. Only Soil 9 (Site 2) was used in this study. Sites 1 and 5 had homogeneous soil conditions throughout the three replications. WD=well-drained; SWPD=somewhat poorly drained; PD=poorly drained. si1=si1t loam; ls=loamy sand; sl=sandy loam: c=clay; cl=clay loam: g=gravel. I l Soll I | 6 I 5°" l wpo ' 5 I 3! Son 3 1+; pp 1...] SWPD I II I 8" ' LL, \_\ ' I ' Soll I 4 | C 4 J PD l l I I ' l ' 31-7 ' I Soil 7 I $0" | 8 swpo ' PD Isl II I | l I I ' l _l I I I 10 I 9 l I I ' Soil 9 "17 wo '1 ’ cl I l Soll t ' 10 ' o l I l . REP 1 REP 2 REP 3 oregano ham>awmooxoucm .omeamho aduoon aHmSnnm> .oeewmne fiancee amrxoscmuamzw .oocamuviaaozuoa \m smoH amHouHo .smoa heHo haaamuaoam .seoH pfiamuaum .seoH husmmuaw .osdn aseoauma .ecmnum \fl remakes: amazoavhma ems» Mom mcampw Human no choc How hosoaoamco moanedo:« a \M msazoamnm .moavaosni \m 1C) s.H n - o- no r m.- n can fine: .mr .om s.e o.e o- so a m.- an ems seesaw m A.H :Houmuno\m was no r e.H ma Hos nm-H .mm .mm m.o m.s we as s r.- as earn encore : r.H one a.- Hoar no: Harm .so am e.r m.: on so a r.- Han earn runraom n I r.H Hoar I m.H -o How «cum ran .Hm -.a e.~ - a.- so a: horse: .m I m...” m . n.H ms . r semm sen or m s m m - a a \N ma \m as armor-mg H m: do x m so om so ON 0» \mfisov wcdhoao a Am20\smv So oc.on=»xoe omeeanua moauom Hdom .02 \m Aor\rrv so o~-o on ARV posse: mosssoz so or.ansnsoa so or. snow Hsom mom scam manner Hmonsoro snow re oncomso on snare so or. x-sm so on. Hanson: .mmeoao nuance odes»: 0: mo :Sxoum errata arcane wcdaoommm muoromm mane Hmoasezo can Heoamacm .a cane? 11 Table 2. Forty hybrid poplar clones planted by PCA in clonal trials in 1979 over five SCS soil texture and natural soil drainage classes. CLONE NUMBER CLONE PARENTAGE SEX NE 16 P. pgggg var. charkowiensis x P. deltoides - NE 19 P. gig var. charkowiensis x P. 11% var. - caudina NE 20 P. nigga var. charkowiensis x P. nigga var. m caudina NE 32 P. deltoides var. Eggulata x (P. x f berolinensis) '— ' NE 47 P. maximowiczii x (P. x berolinensis), cv. f 'Oxford' NE 207 ‘P. deltoides x‘P. trichocarpa m NE 209 .P. deltoides x P. trichocarpg m NE 214 ‘P. deltoides x'P. trichocarpa m NE 224 'P. deltoides x P. nigga var. caudina m NE 225 P. deltoides le. nigga var. caudina f NE 238 P. deltoides x P. gigga 'Volga' m NE 252 P. deltoides var. gggulata x P. - trichocarpa NE 253 P. deltoides var. Eggulata x P. f trichocarpa NE 255 ‘P. deltoides var. aggulata x‘P. f trichocarpa NE 264 P. deltoides var. a_._ngu1ata x P. 11% f 'Volga' NE 265 P. deltoides var. gggulata x P. niggg m 'Volga' NE 274 P. deltoides var. occidentalis x m P. simonii NE 298 P. nigga var. betulifolia x f P. trichocarpa NE 299 P. nigga var. betulifolia x f P. trichocarpa NE 300 ‘P. nigga var. betulifolia x m P. trichocarpa a'NE 308 ‘P. nigga . charkowiensis x m P. giggg 'Incrassata' 12 Table 2. Forty hybrid poplar clones planted by PCA in clonal trials in 1979 over five SCS soil texture and natural soil drainage classes (continued). CLONE NUMBER CLONE PARENTAGE SEX NE 316 P. nigra var. charkowiensis x m lP. x euramericana 'Robusta') NE 318 ‘P. giggg var. charkowiensis x P. deltoides f NE 346 ‘P. deltoides_x P. trichocagpa f NE 348 P. deltoides x P. trichocarpa m NE 351 P. deltoides x P. nigga var° caudina m NE 353 P. deltoides x P. nigra var. caudina, cv. m 'Red Caudina' NE 359 P. deltoides x P. gigga var. caudina f NE 373 P. deltoides var. Egggéa£a_x P. trichocarpa m NE 375 P. deltoides var° angulata x P. nigra m var.‘plantierensis NE 386 P. 'candicans' x (P. x berolinensis) f NE 388 P. maximowiczii x P. trichocarpa, cv. f '— THingston' '— DN 17 P. x euramericana cv. 'Robusta' m DN 18 P. euramericana cv. 'Tardif de m Champagne' DN 28 P. x euramericana cv. 'Ostia' - DN 30 P. x euramericana cv. 'Canada Blanc' m DN 31 P. x euramericana cv. 'Negrito de m Granada' DN 34 P. x euramericana cv. 'Eugenei' m 145/51 P. x euramericana cv. 'I45/51' - Raverdeau .PP. x euramericana cv. 'Raverdeau' m m=ma1e, f=female, - =sex unknown 13 Within and across-site variation and significant differences were ' determined using standard ANOVA and multiple range tests. RESULTS AND DISCUSSION Description of Clonal Trial Sites All five sites are indicative of "marginal" agricultural land in the economic sense. Site 1, a drouthy, excessively drained (ED) Kalkaska sand was originally forested with good northern hardwood timber, but current agricultural potential depends on physical site alteration since logging as well as past cultural use. This site was a cleared area surrounded by natural forest and a pine plantation. There was no indication of cropping for several years prior to planting hybrid poplar in 1979. The loamy sand Ap horizon (surface or plowed layer) had.only 2.2% organic matter and a pH of 4.5. The E horizon just under the Ap was strongly-leached and lacking in organic matter and essential soil nutrients. Soil nutrient requirements have not been clearly determined for hybrid poplar under intensive culture, but K, Ca and Mg were defic- ient in 1981 based on nutrient needs for moderate production of corn or small grains. Coarse sand occurred below 45 cm to a depth greater than 2.9 m. Moisture is held briefly in the Ap, then percolates rapidly through the deep, coarsely-textured profile, making itED. Site 2, a well-drained (WD) Nester loam, was one of the most productive agricultural soils after early logging. The original soil surface was a loam but repeated cultivation for corn left topsoil bare of cover and subject to wind erosion. The rolling terrain with slopes of up to 20% contributed to surface erosion from overland flow. The 0.4 ha clonal trial is situated at the top of a slope where erosion 14 has removed the original loam surface leaving a clay loam B horizon, which is now the Ap. .Bulk density of the surface was 1.6 gm/cmB, indi- cating soil compaction from rain splash or trafficing during wet soil conditions. Surface infiltration of moisture is reduced and limited to downward movement through the moziac of cracks in the soil. Soil moisture will enter this way but must spread out laterally throughout the profile horizons (TroUSe 1971). The upper B horizons had a bulk density of 1.7 gm/cm3 showing a compact, dense subsoil as well. Internal soil drainage is slowed due to the clay loam texture and compaction, yet it was still within the WP classification. while physical 8011/ site factors were not ideal, the nutrient status was good in 1982. The pH of the Ap was 7.1 and only P was deficient, based on requirements for moderate corn production. Site 3 is a somewhat poorly drained (SEPD) Selkirk silt loam over a silty clay. "Somewhat poorly" indicates natural soil drainage is impeded between 15 to 51 cm from the soil surface, causing partial saturation throughout the year or at specific times during the year. Alternate saturation and drying produces gray or yellow-brown mottling, which is one of the several factors used to determine SCS natural soil drainage classes. Soils like this one with reduced drainage usually have a slowly-permeable layer in the B horizons, a seasonal high water table and/or additions from overland flow (floodplain) or internal seepage. Site 3 had silty clay loam and silty clay B horizons with bulk densities of 1.7 and 1.8 gm/cm3, indicating that the subsoil was severely compacted in this fine-textured soil (Knighton 1975). The compact soil plus saturated conditions for part of the growing season 15 limit internal soil aeration. As the soil profile becomes wetter, uptake of moisture and nutrients may be reduced due to lessened root respiration and plant metabolic functions (Russell 1977). Except for K, nutrient status of the soil was sufficient for corn or small graiDS. The pH of the Ap was 6.7 in 1982. Site 4 is an Ogemaw sandy loam, SWPD, with a sandy loam Ap over an orange intermittently-cemented coarse sand (due to iron content and fluctuating water table), with mottles occurring at 46 cm. There was reduced drainage in the spring due to a high water table and slow permeability through the cemented sand. Once drained, however, the coarse sand was very drouthy. An increase in mottled clay at 100 cm indicates a saturated zone occurring at or just below that level. The pH of the Ap was only 4.5 and both P and K were deficient for corn or small grains in 1982. Site 5 is a very poorly drained (VPD) Granby sandy loam with variable, stratified soil horizons on an outwash lake plain. The surface is a black, mottled sandy loam with 7% organic matter. The Ap (34 cm) lies over a deep (greater than 3 m) gray, gleyed sand. The site is submerged for much of the growing season and the water table in August, 1982, was no lower than 18 cm from the surface. Three trees were care- fully excavated with roots intact in 1982, and none of the tree roots occupied a soil volume larger than 20 x 20 cm, total. Both P and K were deficient in 1982 and the pH of the Ap was 5.8. Clone Performance Across The Range of Sites Analysis of variance and a Student-Newman-Kuels multiple range test showed significant differences in average 4-year height growth of 16 all clones combined across the range of five SCS natural soil drainage classes (Figure 2, Table 4). Best 4-year height growth occurred on Site 2, the WD Nester clay loam which was the best soil in this study (Table 3). Clones NE 19 and NE 359 had heights of 6.6 and 6.4 m, or between 1.6 and 1.7 m growth per year. Nine clones grew to between 5.1 and 5.9 m (1.3 to 1.5 m per year). The remaining 29 clones had heights between 3.0 and 4.9 m, or 0.8 to 1.2 m growth per year. Table 4. Two-way analysis of variance showing effects of site, clone and site by clone interaction on 4-year height growth of hybrid poplar clones in clonal trials over five soil/site conditions. 1/ Source SS df MS F Site 668.3 4 164.6 79.73 0.001 Clone 86.4 38 2.3 1.10 0.500 Site x Clone 240.3 152 1.6 0.77 ns Error 555.3 269 2.1 l/Heights for 39 of 40 clones were used for this analysis because one clone had only one observation. There was a high incidence of both Septorialmgggza (Peck) leaf SP0t and stem canker on Site 2. A comparison of 1981 tree heights (furnished by PCA) and 1982 heights showed that some trees died back in 1981 and resprouted in 1982. Other trees had §. mg§ixa stem canker in the upper 1/3 of the tree canopy, causing top kill and a reduction in height. Figure 2. Influence of natural soil drainage and soil texture on average 4-year height growth of 40 poplar clones. Sites 1 and 5 are not significantly different from each other. All other comparisons are significantly different at P:0.01. s=sand, cl=clay loam, sil=silty loam, sl=sandy loam. 17 ) Height (m _..a:.__.__.__.___._.___..___.__. m“... 0.0 wm O s ‘ 1 I I E I u t a N 3. Site 5 Clone Ht. 3. Site 4 Ogemaw sl SHPD Granby sl VPD Clone Ht. 18 an} Ht. 3. Selkirk ail SW?!) 5. Clone Site 2 Nester cl WD poplar clones on 5 sites representing a range of SCS soil texture and natural Clone Ht. soil drainage classes. Ranking of 4-year average height growth (m) and survival (5) of 40 hybrid 3. my Table 3. Site 1 Kalkaskn s lone Ht. Q U wereewrmm 9somwsnonwnrwmmurwmmnmnwremnno 1 ooooo993777775somtnoASSJAAAJJSJJJJJJraan 2«4222111.111.1111s.llll1.11 Lllfi.llw.llll‘¢lllll n47%m856294 79.31.024.398 even 3858 38591 151 .725 331w 759mm1 158 53 544w03% 3 4 3 35 2 a T. y 1130213339....122 V03). .2 2 mm-mmmmmmmmmmmmmwrwwrammmwmwmmmmmmmmanmm mmo:oc mm wwmmmmow.mmoro%wommwmmmmrmo m:m 1&1111111. .l «A ll 1 llouollloo.l 200987910204I4.“ 3232211.000998856655554 5533221 5.3433333333333333333322222222220~2I~2a£2222 @6898 8653 1882247947 03 swmmm iris.mn.srrvawasizaaormaiwsirzfimoru mama rammmmm mmmmwrmmmiwmmrmrnmmmmmnrmmrmw IEV ram mammary moreormmmm omemorrmo mmrrmmrr 309211199888777zOIO555hw-432422210098755.“ 501014 6 54.4. 4.4. 4. 333333333333333333333332 222222221 7 517 1812 345 85988-017 88 839 582 9 u i r r ow uozir9 or 5429 3 “<2, firfimypmnfiam max 3322 13%....) mmrrwwm MEMEmmmmmmmmmmmmmmmmmmmmmmmmmmmmm o ”wmwwmo mmsovmv. 3:w%mwwm WZo wflwmwo BMwfiflwflm l .uw9937053210388765555“332110009Qv7nl665.31¢0 5655555555544444444444444444443333333333 messiArn were» mmrrmmmmn rammmrmsr new 39 3- 23 v.2 32m 32 2 33 3 32 mmmmmm m:mm mm :.H momsmnmzm.mmrmrwmnmmmmm .. u fiwmwmmfifl.rrmEWErawrwmrwmwflflwmeo w:wNWWW 7.4.3220.998.oq257.6.5 055544443.5322222111019956 2..“22221Llllll.-.ll. I.11111111111111111110.JOO 970 91643.98 25537888551 $641 330734898$2 . 8 2 552: 3, , 75 3 5 3119 11 144-02255. 3W; 2223,.nwa2m2 , 3yun3n6 27 . L513: are re mrmemreess:eemrrnrmmmmmme manners . Mean site 69 3.4 85 3.1 92 4,6 3D-excossively drained, WD-woll-drainod, SWPD-somewhat poorly drained, VPD-vory poorly drained E/ s-sand, cl=clay loam. sil=silt loam, sl=sandy loam 19 As internal soil drainage diminished (Sites 3, u and 5), 4-year height growth was significantly reduced (120.001). Clones on Site 3, the SWPD Selkirk silt loam, had 4eyear heights mostly from 3.0 to over 6.0 m, but 10 clones only grew from 1.4 to 2.9 m. On Site 4, the SWPD Ogemaw sandy loam,‘48% of the clones grew to less than 3.0 m and only three clones reached heights of over 4.0 m. On Site 5, the VPD Granby sandy loam, 35 clones grew to less than 2.0 m in 4 years, while the other five clones reached a maximum of 2.0 m growth. Site 1, on which 4-year height growth was not significantly different from Site 5, 34 clones grew to less than 1 m. Sites 1 and 5 are the extremes for the study and cannot be considered suitable for poplar plantations. Table 5 illustrates the magnitude of change in 4-year height growth of hybrid poplar on sites other than Site 2 which had.the best conditions for this study. "Best" clearly means best of five marginal old fields, Table 5. Percentage change in 4ayear height growth of hybrid poplar clones when planted on sites other than Site 2, which represented the best in this study. Percentage Average change Site Ht. (m) from best 1 1.5 -67 2 4.6 Best in study 3 3.4 -26 u, 3.1 ~33 5 1.6 -65 20 all exhibiting some negative physical site factors. In Chapter 2. the "best" site (literally) was a WD sandy loam with no detrimental factors; 5-year height growth for NE 308 (one of the tallest in the present study) was greater than 9.0 m. Other factors besides soils must also be considered when evaluating growth and survival of the 4-year-old poplar clones across the range of establishment (1979) included herbicides plus cultivation prior to planting and throughout the first growing season. These treatments controlled vegetation competition sucessfully according to PCA records. Weed competition in 1980 and 1981, however, could have been an important“ factor, as the trees on Sites 1, 3, # and 5 had not reached crown closure in 1982 and could not shade out the weeds. Diameter of unrooted cuttings used to establish these plantations could have affected initial estab- lishment and subsequent height growth of clones, and may indicate why survival of some clones were very low. Cutting diameter was noted to vary from 0.9 to 1.9 cm in PCA records; Dickmann and Stuart (1983) state cuttings should not be less than 1 cm in diameter. Within Site and Individual Clone Performance There were no statistically significant differences in 4-year height growth among the 40 clones on any of the five sites (Table 4). This may be explained by the lack of consistent replication as a result of redefining homogeneous soil boundaries. Figure l-B. for example, shows the loss in replication due to the identification of two distinct soil texture and natural soil drainage classes on one 0.4 ha clonal trial. Where there might have been 15 observations per clone on any one clonal trial (3 replications of 5-tree plots), there was hardly more than one replication on soil number 7 (Site 4); with mortality, some clones had 21 only 1 to 3 observations, although the average was 8 to 12. This problem existed on Sites 2, 3 and u (Figures 1 A-C). On Sites 1 and 5, soil/site factors were homogeneous across the three replications; the absence of significant differences in height on these two sites may be explained by the extremely adverse conditions. Site 1 is extremely drouthy while Site 5 is saturated (anaerobic conditions) for most of the growing season. Hybrid poplars can survive on such sites, but energy for growth is sacrificed. NE 359 (P. deltoides x P. gigrg var. caudina) had the best overall 4-year height growth, considering all five clonal trial sites (Table 3). This clone was also in the highest ranking for 4fiyear height growth in both Pennsylvania and Maryland (Demeritt 1981). NE 359 is recognized as having good rooting ability, survival after the first year of 90% or better, and tolerance of late spring and early fall frosts in mid- Michigan.l/ Table 6 identifies the ten hybrid poplar clones with best h-year height growth on Sites 2, 3 and 4, the kind of sites recommended for production plantings using intensive culture on marginal farm fields. NE 22#, 225 and 351 are all P. deltoides x P, nigra var. caudina parentage. NE 351 also was in the top six clones in the Northeast United States (Demeritt 1979). Demeritt (1981) reports NE 224, 225 and 351 are still alive and 65, 48 and 46 cm dbh, respectively, in a 50-year-old planting in Frye, Maine. NE 308, P, nigra var. charkowiensis x 25 Eggga 'Incrassata' and NE 20 were in the top rated clones in both Pennsylvania and Maryland Demeritt 1981), and in the top six in a Northeast study by Demeritt (1979). Data from Chapter 2 showed that NE 308 grew to 9.0 m in five l/’Dickmann, Donald I. 1983. Description of Individual Poplar Clones and Cultivars. Unpublished Manuscript. Department of Fbrestry, Michigan State University, East Lansing, MI 48824 22 years on a WD sandy loam in a county adjacent to this study. Dickmann 3/ indicates NE 308 is frost hardy, an excellent rooter and one of the best NE clones in terms of growth, form and canker resistance. NE 20 was ranked as a superior clone in Brissett 33 a1 (1979). NE 2389.2! deltoides x P. nigra 'Volga' was not an outstanding clone in other clonal trials, but performed well in this study. Table 6. Fourayear height growth of the 10 tallest hybrid poplar clones on the three most productive sites in this study. Site 2 Site 3 Site 4 Av. Ht. % of Av. Ht. % of Av. Ht. % of (m) Site Av. (m) Site Av. (m) Site Av. Avg. of all clones 4.6 3.4 3.1 NE 359 6.4 139 6.3 185 5.2 168 NE 308 5.9 128 3.9 115 3.6 116 NE 225 5.9 128 4.2 124 3.2 103 NE 351 5.8 126 3.9 115 4.3 139 NE 20 5.6 121 3.7 109 3.8 123 DN 34 5.7 124 3.8 112 3.2 103 Raverdeau 5.3 115 3.7 109 3.4 110 NE 238 5.2 113 3.3 97 3.4 110 UN 31 4.9 107 4.1 121 3.1 100 NE 224 4.7 102 4.9 144 3.9 126 Rayerdeau, DN 31 and DN 34 are all P. x euramericana clones of European origin. Raverdeau had.excellent 2-year heights of 2.8 and g/Ibid. 23 2.7 m on sites with soil drainage altered by ditching under no-till culture in the same county as this clonal trial study (Chapter 3). Dickmannj/ warns the clone is susceptible to §_. M canker if planted on poor sites. DN 34 was one of the superior clones in Brissett et a1 (1979). Also known as Carolina or 'Imperial' Carolina Poplar (distributed by SCS Plant Materials Centers), DN 3n had 2eyear heights of 4.8 m when planted as agricultural windbreaks on sandy loam soils in Lower Michigan (Woods and Hanover 1982). It is important to note the superior performance of P. x euramericana clones, which represent various hybrids of P. deltoides x 2. $5113. In this study, 8 of the top 10 performing clones had this parentage. The other two were pure 2. Ilia hybrids. All other crosses in this study show poor height growth and/or high susceptibility to §. musiva (Moore 1984). P. x euramericana clones achieved best growth on WD, sandy loam or loam sites and are exacting in these requirements (Chapter 2 and 3, Dickmann and Stuart 1983). Figure 3 shows the extent to which site quality affected height growth of four of the tallest P. x euramericana clones in this study. NE 308 and NE 20 are two _P. EEZE x P. alga crosses which were among the 10 best-performing clones in this study. NE 308 was also the most productive clone in the PCA study in Chapter 2. While normally considered quite resistant to S. _m_u_si_v_a leaf spot and canker, severe infestation of _S_. musiva canker was recently discovered (1984 growing season) among NE 308 individuals in PCA plantings containing two other highly susceptible clones of different parentage (Moore 1984). It may be wise to be conservatively optimistic about _P. _n_i_5r_a_ x 2. gig crosses 3jI'bicl. Figure 3. Fourfiyear height growth of four fast-growing P. x euramericana hybrid poplar clones with strongly exacting site requirements. Site 2, although marginal, had the best conditions in the study. 24 4-Year Height (m) 7 5 NE 225 NE 351 4 3 2 . 1 7 6 NE 308 RAVERDEAU 5 4 2 . 1 U! 00 MWD sw BSD MWD SW sw PD PD PD si cl 3| si 8! cl 3! 3| sl site isite 2 site 3 site 4site 5 site 1 site 2 site 3 site 4 site 5 25 based on this information and their extreme susceptibility to Dothichiza populea (Sacc.) canker. This canker terminates the life of P. nigra (Lombardy) in less than 15 years in Lower Michigan. Kelly (1976) found P, nigra clones highly susceptable to D. pgpulea after 6-7 years in plantations at Kellogg Forest near Augusta in the Lower peninsula of Michigan. Analysis of Clone by Site Interaction The results of 2-way analysis of variance (Table 4) show soil/ site variables were the dominant factors affecting 4-year height growth in the five hybrid poplar clonal trials. Although there were not any significant differences in height growth between clones on each site, loss of replication due to redefining clonal trial boundaries for homo- genity may have strongly affected this analysis. Nonetheless, there were considerable differences in height growth among clones on Sites 2, 3 and 4. The lack of a significant clone x site interaction indicates that the pattern of height growth for each clone was similar across the range of sites. Figure 3 shows the general shape of this response. CONCLUSIONS Perhaps the most significant observation to surface in this study was that tremendous soil variability can be encountered in only 0.4 ha (Figures lA-lC). The three-replicate design was not nearly sufficient to handle the variation uncovered by detailed soil mapping and evaluation. If such a soil evaluation had been done before the sites were accepted, Site 3 with four totally different soil/site conditions would, most likely, have been eliminated in favor of a more suitable site. Site 4, with two different soil/site conditions could have been used to take 26 advantage of the differences by expanding replication within the identified homogeneous areas, giving two possible sites. The areas with gravel deposits on Site 2 could have been eliminated from the replications. This raises the question "How much credibility can be assigned to many genetic tests reported in the literature?". Most of these studies identify one soil type (with or without naming soil series) without giving any description of site evaluation procedures. The researcher and subsequently the reader, assumes inherent site variability is taken care of in the experimental design. With the tremendous soil variability encountered in the glaciated portion of Lower Michigan, it appears a detailed analysis should be the rule, not the exception. Additional factors such as severe soil compaction and/or plow pans associated ‘ with agricultural fields must also be considered. If a WD loam or silt loam soil is selected, for example, and is determined homogeneous in that soil texture and natural soil drainage condition, unidentified factors such as soil compaction or plow pans will have a definite effect on tree growth, as shown in Chapters 2 and 3. In future clonal trials, it is suggested that the assumption not be made that replication alone will be sufficient to account for inherent soil/Site variation. Rather, a thorough soil/site analysis should be made and the experimental design tailored to the pattern of soil variability encountered. 27 REFERENCES Barkley, B.A., R.W. Evers and W.E. Raitanen. 1983c. Soils: the forest foundation. In: New Forests in Eastern Ontario: Hybrid Poplar. Science and Technology Series, Vol. 1. p. 63-82. Brissett,J.C., J.W. Hanover, T.J. Stadt and J.W. Hart. 1979. Improved poplars for Michigan through the Michigan State Cooperative Tree Improvement Program. In: Proc. North Am. Poplar Council, 1979, Annual Meeting, Thompsville, MI. p. 115-122. Demeritt, Maurice E. Jr. 1981a. 50 years of hybrid poplars in the northeast. In: 27th Proceedings of the Northeastern Forest Tree Improvement Conference, 1981. p. 166-183. Demeritt, Maurice E. Jr. 1981b. Growth of hybrid poplars in Pennsylvania and Maryland clonal tests. USDA For. Serv. Res. Note NE-302. 2 p. Demeritt, Maurice E., Jr. 1979. Evaluation of early growth among hybrid poplar clonal tests in northeastern United States. In: Proceedings 26th Northeastern Tree Improvement Conference. p. 166-183. Kelly, Richard P. 1976. Growth, canker susceptibility and rooting of Populus deltoides and other Populus clones in Southern Michigan. Unpublished Ph.D dissertation, Department of Forestry, Michigan State University, East Lansing, MI 48824. 63 p. Moore, Lincoln M. 1984. The major insects and diseases affecting intensively-grown hybrid poplar on Packaging Corporation of America lands in central Lower Michigan. Unpublished Ph.D Dissertation. Department of Forestry, Michigan State University, East Lansing, MI 48824. 157 p. Schreiner, E.J. 1974. Poplars can be bred to order for mini-rotation fiber, timber and veneer production and for amenity plantings. In: Proceedings 21st Northeastern Forest Tree Improvement Conference 21:85-96. Trouse, Albert C., Jr. 1971. Soil conditions as they affect plant establishment, root development and yield. In: Compaction of Agricultural Soils. ASAE Monograph, Am. Soc. Agron. Eng., St. Joseph, MI 49085. p. 122-149. Woods, Ruth F. and James W. Hanover. 1982. Growth of Imperial Carolina Poplar over a range of soil types in Lower Michigan. Tree Planters Notes. 33(2)8-13. CHAPTER II EFFECT OF SITE ON HEIGHT AND DIAEETER GROWTH OF THREE HYBRID POPLAR CLONES UNDER INTENSIVE CULTURE 28 29 INTRODUCTION Research involving soil/site factors which contribute to optimal productivity of hybrid poplar indicates a need for taking a reasonable and somewhat conservative approach to planning a large-scale planting operation. Several studies point to specific, demanding site requirements for hybrid poplar. Dickmann and Stuart (1983) describe hybrid poplar as being able to grow almost anywhere, yet being exacting in site demands for optimum growth. Jones and Grant (1983) say poplars must be planted on "reasonable sites" with "favorable growing conditions". Zsuffa (1975) found hybrid poplar clones differing in their individual site requirements and concluded specific clones were needed for certain site conditions, rotations and management systems. Baker and Broadfoot (1978) were even more specific when referring to site requirements of eastern cottonwood (Populus deltoides) and assumed each of the major site factors is responsible for a certain percentage of tree growth. What, then, are the characteristics of sites which produce optimum or reasonable-yet-favorable growing conditions? This chapter reports on height growth of three hybrid poplar clones planted across a range of sites on a large-scale commercial basis by Packaging Corporation of America (PCA), a corrugating medium pulp and paper mill located in north- western Lower Michigan. The major focus of the study was to assess the effects of variations in soil texture and natural internal soil drainage on tree growth. This information,.then,cou1d be used to identify those sites which have optimum conditions for hylrid.poplar productivity, those which have moderate to good potential for a range of uses and those with little or no potential. 30 MEHHODS Site Selection Selection of research sites which characterize a full range of soil textural and natural soil drainage classes was essential. Potential sites were chosen using USDA Soil Conservation Service (SCS) Soil Survey maps followed by verification of soil conditions in the field. Each site was mapped for soil variation. Color of and depth to mottling, base soil color and depth to water table (if less than 2 m from soil surface) were used to establish natural soil drainage class. Surface soil texture was determined in the field and used to identify SCS soil series. Areas within a site which varied significantly from the dominant drainage and texture were not used. Final site boundaries were drawn to encompass homogeneous areas of from 2 to 8 ha. Nine sites in Mason and Manistee Counties were selected representing sandy, loamy, clay and muck soils. Natural soil drainage classes include excessively drained (ED), somewhat excessively drained (SWED), well-drained (WD), moderately well drained (MWD), somewhat poorly drained (SWPD) and poorly drained (PD) . Soil/Site Analysis One soil profile description was done on each of the nine sites. Soil horizons were described in June, 1982, to a depth of 154 to 240 cm, depending on depth from the soil surface to the parent material or C horizon. Samples were taken from each horizon and sent to the Michigan State University (MSU) Soil Test Laboratory in East Lansing, MI for mechanical analysis (% sand, silt and clay). Current SCS soil series were then verified. Analysis for P, K, Ca, Mg, pH and organic 31 matter was done by the MSU Laboratory and soil bulk density at 20, 40 and 60 cm was determined. Analysis of N was not done because this nutrient is highly variable in form and quantity from season to season. Understory vegetation Analysis No quantative data were available on the extent of vegetation competition on each site during the year of establishment or for the first three growing seasons; only general field observations were avail- able. To analyze current understory vegetation on the nine sites, species and dry biomass evaluations were made in August, 1982. Species were recorded on 20 randomly placed 0.5 m2 circular plots per site and all plants within the plots were clipped at ground line, dried at 105°C and weighed. Tree Growth Evaluation Four and five-year tree height was used to evaluate hybrid poplar productivity on nine sites. Total height and diameter at 15 cm from the ground of thirty trees of each of three clones were measured in September, 1982. Clones measured were (1) P, nigga var. charkowiensis x P, nigga Incrassata cv. NE 308, (2) P. maximowiczii x (P. x berolinesis) cv. Oxford (NE 47) and (3) Poplar X, an unknown Aigeriros x Tacamahaca hybrid, which was mislabeled by an early nursery supplier. Pop. X, NE 47 and NE 338 were originally received in a mixed lot from the nursery and planted without knowing the proportion of each clone in the mixture. Neither survival nor tree heights were measured prior to this study. To obtain an estimate of survival (total on site) in years four and five, an inventory was taken which identified each tree and open 32 space based on the original 2.4 x 3.0 m spacing within plot boundaries. Stocking of individual clones at each of the nine sites was calculated. Data were analyzed using standard ANOVA procedures and Student-Newman- Keuls test for significant differences. Pest Incidence Evaluation All trees measured for each of the three clones were evaluated for insect and disease incidence in August, 1982. Field assistance was furnished by the North Central Forest Experiment Station (NCFES) in East Lansing, Michigan and the Department of Forestry, Iowa State University (ISU) personnel. A NCFES rating scheme (showing incidence from trace to severe) was used to determine severity of various pest organisms by site. — Percentages of pest incidence per pest organism for each clone (total of all trees/clone) were also determined. RESULTS AND DISCUSSION Growth of Clones Site factors used to evaluate the quality of the former agri- cultural fields in relation to potential productivity of the three hybrid poplars included (1) previous site history and use within the five years prior to planting (2) current soil nutrient level compared to the requirements of the previous crop, (3) landform, (4) soil structure, (5) order of and development of the various soil horizons, (6) soil bulk density and (7) site preparation in the year of estab- lishment and site maintenance beyond year one and (8) understory vegetation biomass during the 1982 growing season (Table 7). 33 1 Table 7. Physical site factors J affecting hybrid poplar height growth. :ZOGI y Neutral :ZOcn marmos- Vegetation Plantation Soil 3011 Soil Soil :40cn Den. :60cn Competition Site timber Drainage Series Texans-u Text.:60cn (gm/m3) (kg/ha) find after 5 Years 1 Springdale 4 ED W ' Typic s 1.5 1704 haplorthod s 1.6 15 1.6 2 L'arilla 1? 3322) ilancelona Alfie 13 1.3 972 haplorthod gr. 13 1.4 5:. 15 1.4 3 Zleon 3 iii) Iiontclam Entric 13 1.4 1239 glossoboralf ls 1.5 a g 2.3 1.6 4 Bear Lake 2 TD kmet 'I‘fpic 51 1.3 1551 entroboralf ls 1.5 31. 10" Evaluated after 4 Years s more: 25 23:3 Seward Arenic s1 1.6 2573 hapludal! SCI 1.? W” scl 1.7 6 Ingan 24 I‘I'JD Perrington 'Zypic cl 1.6 3024 eutroboralf cl 1.? sicl 1.7 7 Riverton 25 32-.‘PD Iosco Alfie 31 1.4 2537 haplaqmd 31 1.5 3C1 1.? Evaluated after 5 Years 3 Diaple :2th inch Aerie s 1.4 1924 Grove 29 haplaquod s (ortstein) 1.5 s ortstein 9 :‘aple PD Iacota. Mollie l (muck) 1.1 $81 Srove 29 haphquept s -- 2/ sic «- ;./ 23=excessively drained, SUSS-somewiut excessively drained, ZiD-well-drained, :‘fwkmodentely well drained, SZ‘GDasmmat poorly drained, I’D-poorly drained. s=sand, 15'1an sand, gr. Isa-granny lam sent, sl=sandy loan, scl=sandy clay loam. cl=clay loan. sicl=silty clay loam, liloan, sicasilty clay. 3/ PCA gave their hybrid poplar plantations embers consisting of township name and section amber. For example, Springdale is the township: 4 is Section 4. 1 . J Bulk density could not be measured because soil was in suspension due to water table. 34 An analysis of variance of 4- and 5-year hybrid poplar height growth (Figure 4) showed significant differences (P:0.05) in performance among SCS natural soil drainage classes and with changes in soil texture within drainage classes. Diameter growth was found to be highly correlated with height growth (ra=0.74) (Table 8). Best 5gyear mean height growth differed significantly (with the exception of NE 47) between Site 8, a SWPD sand over a cemented ortstein, and Site 9, a PD mucky loam over gleyed sand; these two sites differed from Sites 1 through 4 (all 1978 Plantings). NE 47 had similiar performance on Sites 1 and 8, the two extremes of dryness. Although Site 8 is classed as SWPD, it is as drouthy as Site 1 once soil mlisture percolates below the cemented sub- soil. Four-year height growth differed significantly (339.05) for all three clones among Sites 5, 6 and 7 (a MWD sandy loam, a loam over heavy clay and a SWPD loan with a heavy clay subsoil). These soils have restricted internal drainage which can cause excessive moisture within or near the rooting zone of the trees for all or part of the growing season 0 Optimum Conditions For hybrid Poplar When considering the older (1978) plantings as a separate group (1978 and 1979 plantings had to be analyzed separately), Site 4 (Bear Lake 2) a WD Emmet sandy loam had "optimum" soil/site conditions for the three hybrid poplars in this study: NE 308 had mean 5-year height of 9.4 m and mean diameter of 13.6 cm (Table 8). Two other studies in Lower Michigan also identified WD sandy loam soils as optimum for hybrid poplar. Soil nutrient levels for P, K, Ca and Mg in the fifth year were still at levels recommended for dry beans. The surface soil pH was 5.5. Figure 4. Influence of natural soil drainage and soil texture on height growth of three hybrid poplar clones in nine research sites. 35 m. 2R. Q use.“ MQEE $0M. Q2... MQSSYQQ «Sm. qgsk 9.2 k 3.3 h 63$. :60. Scam >o_o\Eoo. oases :58 oozes :o; .3368 222306 soap. c_2m...o\v5m 3:66 ooEEo blood recon .2558 . J $6.5 $19.6. - _ RN30 t3$¢3 .0 than £00. 3:9... 3:66 :9: 320309: Q a.“ M. a.“ N 6&9. \ 65$. _ econ >68. econ Eco. >28 scam >602 3506 202385 7 8:66 3520 :2, 3:66 :03 .3562. 202333 _ . _ _ T 831:0 llv RG3 c.3973 3331\le RD .0 m be B QM, 33.1.6359 >33 3‘ M? m m\ more to an N? I O.N m? p m h more to X .QoQ l 0.? 1 Cd 1 06 L 0.0. it» 1:05 ktbxhl >363 36 Table 8. Description of 4- and 5-year mean height and diameter growth, of 3 hybrid poplar clones on nine research sites. (H gr (X) 27 Plantation.l/ Mean Mean Site Number Clone Height (m) Diameter (cm) Evaluated after45 Years 1 Springdale 4 Pop. x 4.1 if 1.0 a y 7.4-:- 2.6 NE 47 3.2 ; 1.2 a 5.4 1 2.4 NE 308 3.3 - 1.0 a 3.2 — 1.0 2 Marilla 17 1°6pr x 5.6 i 1.0 5/ 8.7 i 1.4 NE 7 --- --- --- --- m3w 7milm moiLo 3 Cleon 3 Pop. x 6.5 $- 1.4 c 9.2 f 2.9 NE “’7 601+ 1 009 902 1' 109 NE 308 7.7 - 2.1 7.7 - 2.1 4 Bear Lake 2 Pop. x 8.9 $ 1.4 c 13.6 E 2.6 NE 47 7.3 3 1.4 10.4 ; 2.1 NE 308 9.4 — 1.2 9.4 — 1.2 Evaluated after 4 Years 5 Custer 25 Pop. x ~ 5.3 {- 1.1 7.3 I- 1.0 a. NE 47 .501 ; 1.3 6.2 3; 1.3 a NE 308 .6.2 - 0.9 7.4 - 1.3 a 6 Logan 24 Pop X 4.7 E-l.0 7.3 E 1.0 a NE “’7 “’03 l 009 502 1 103 av NE 308 5.6 -l.l 6.5 - 1.6 a 7 Riverton 25 Pop. x 3.1 E 0.7 3.6 $- 1.5 a. NE 47 3.0 3; 0.7 3.2 1 1.2 a NE 308 3.8 — 0.9 4.6 — 2.0 a Evaluated after 5 ears 8 Maple Pop. x '3.0 E 0.9 4.1 $ 2.1 Grove 29 NE 47 *2.9-— 0.9 a 4.1.. 2.4 NE 308 --- --- --- --- 9 Maple Pop. x 3.0 {- 0.9 4.1 E 2.1 Grove 29 NE 47 2.9 - 0.9 4.1 - 2.4 l/ECA gave their hybrid poplar plantations numbers consisting of township name and section number. For example, Springdale is the township; 4 is the section. x = 1.160x + 0.708, x = diameter; diameter and height were highly correlated, r2=0.74. 4 Hts. and Dias. followed by a’or g_are not sign. diff; all others are at (120.05) . These clones were not planted on the various sites. 37 Site 4 occurs on a ground moraine with sandy loam glacial till parent material. The sandy loam surface had medium granular structure, was very friable and had 3.4% organic matter, allowing good surface infiltration of moisture with a minimum of runoff. Permeability of water through the deep, WD soil profile was moderate. The sandy loam texture to a depth of greater than 185 cm, with small amounts of fine gravel plus 12% clay in bands alternating between soil horizons allows optimum internal soil aeration yet sufficient moisture and nutrients are held for tree roots in the upper l m throughout the growing season. Miller and Gardner (1962) cite layering and bending as significantly influencing water infiltration and movement in soils, resulting in a higher moisture content than is usually found at "field capacity". Pritchett (1979) refers to alternating or banding layers with increased clay content as being highly benefical because of increased soil moisture and fertility. Trouse (1971) found dry bulk density of 1.4 to 1.6 gm/cm3 a severe limiting factor in loam, silt and clay soils. In sand, loamy sand and sandy loam soils, however, a range of from 1.2 to 1.7 is non-limiting. Bulk density of 1.5, 1.2 and 1.6 gm/cm3 at 20, 40 and 60 cm, respectively, in the sandy loam soil of Site 4 indicates good soil structure allowing efficient air and soil moisture movement, and a healthy environment for tree root initiation and growth. In the fall of 1977, the previously cropped Site 4 was deep plowed and disked followed by disking just prior to planting in the spring of 1978. Site maintenance for weed control included cultivation between tree rows three times during the 1978 growing season, followed by applications of simazine (2.8 kg/ha) between tree rows early in the 38 second and third growing season. Understory weed competition in the 1982 growing season was 1551 kg/ha dry weight. Species present were annual/perennial grasses and gypericum perforatum (L.) (St. John's wort). Twenty-two percent of the soil surface was either bare or matted with dead vegetation from the previous year. By 1982 trees from all three clones were effectively shading out most of the understory competition. Survival estimates for each clone on each site were not available because the proportions of each clone planted in l978 and 1979 were not known. Total survival based on the original 2.4 x 3 m spacing on Site 4 was only 30%. This was attributed to cultural problems and not to site quality. In 1978, non-rooted cuttings of all three clones were planted just below the soil surface as an experiment to conserve soil moisture during a very dry year; this technique severely increased cutting mortality. The surviving trees either sprouted from below the soil surface or were planted with the top of the cutting protruding above it. Other hybrid poplar clones were interplanted on this site in 1980 and they are growing at the same average 1.8 m per year rate as the initial trees, with nearly 100% survival. Moderate to Good Productivity Sites Going from optimal to drier conditions, Site 3 (Cleon 3L,a WD Monurflm.loamy sand on glacial till upland, was an old orchard site that had not been maintained for a number of years. NE 47 and NE 308 had mean 5-year heights of 6.4 to 7.7 m which were significantly different (P:p.05) from Site 4. Pop. X performed similarly on Sites 3 and 4. Mean diameters ranged from 6.5 to 7.7 cm. The loamy sand surface with pH of 5.8 and 4.5% organic matter had the same excellent structure and consistency as Site 4 due to many years of manuring and incorporating 39 green cover crops when the site was in orchard culture. In 1982, K, Ca and Mg were at proper levels for apple production, but P was slightly low. The primary difference between Site 3 and Site 4 was the dominance of loamy sand horizons throughout the profile with bands of increased clay between 32-68 cm and between 118-131 cm; on Site 4, sandy loam was dominant plus banding. Soil bulk density was 1.4, 1.5 and 1.6 gm/cm3 at 20, 40 and 60 cm. Understory vegetation competition was only 1289 kg/ha, with annual/perennial grasses and Solidago sp. occurring infre- quently. Many of the taller hybrid poplars were shading out most of the understory competition. Survival of the three clones combined in 1982 was 60%. Site preparation and maintenance in the second year was identical to Site 4, but simazine was not sprayed in the third year. Site 2 (Marilla 17), a swan Mancelona loamy sand, is also situated on glacial till upland, but with a considerable increase in gravel content and size of coarse fragments over Site 3. Previous crop history included corn production through 1977. P, K, Ca and Mg levels for corn were well above recommendations. The loamy sand surface, which had been heavily manured each year, had a pH of 5.9 and organic matter was 5.2%. Downward movement of soil moisture is rapid until it reaches a gravelly BT horizon (increase in clay) at 67 to 95 cm where some moisture is held. Below the Bt horizon and to a depth of 200 cm is a continuous gravelly sand (C horizon). Little or no moisture is held below 95 cm, making the soil SWED. Bulk density was non-limiting. Height growth for NE 308 and Pop. X was significantly different (P:D.O5) (7.0 and 5.6 m) due to a lack of available soil moisture and excessive stoniness which was inhibiting to root expansion. Site preparation and first- and second- year maintenance was consistent with the other 1978 sites and understory 4O vegetation competition in 1982 was the lowest (972 kg/ha.) of the nine sites. Sites 5 and 6 are situations where natural soil drainage is impeded at various depths within the soil profile, causing saturation or partial saturation throughout the year or at specific times during the year. A MWD soil commonly has a slowly permeable horizon within or just beneath the solum (A and B horizons). Somewhat poorly drained soils are wet for significant periods, have a slowly permeable layer within the solum, a high water table during spring and summer months, plus additions from seepage are possible. Gray and/or yellowish brown mottling occurs below the surface horizon or 15 to 51 cm from the soil surface. Site 5 (Custer 25), a MWD Seward sandy loam, was formed by glacial lacustrine deposits overlain by waterlaid sandy loam. Drainage is rapid through the sandy loam surface but is slowed in a sandy clay loam horizon at 23 to 44 cm. Mottles indicated that a seasonally high, fluctuating water table occurred at 100 cm and that saturated conditions exist for a certain period of time at this depth. In addition to some restricted drainage, soil compaction was also a negative factor on Site 5. Compaction involves the compression of solid particles resulting in greater soil density, reduced effeciency in movement of liquids and gasses throughout the profile and rearrangement of soil particles through the rooting zone (McKibben 1971). These direct effects contri- bute to changes in soil moisture, aeration, temperature and penetrability. Bulk density of 1.6 gm/cm3 in the sandy loam surface of Site 5 was non-limiting; 1.7 gm/Cm3 in the lower sandy clay loam and silty clay loam indicated compact soil, particularly at 60 cm, which can have a direct effect on roots. Mean 4-year height growth on Site 5 varied 41 from 5.3 m for Pop. X to 6.2 m for NE 308; this was the best of the 1978 plantings which were analyzed separately. Understory weed growth was greater (2573 kg/ha) on Site 5 than on Sites 1 through 4, indicating competing vegetation made efficient use of additional soil moisture on the MWD site. The dominant weed was Centaurea maculosa (Lam) (spotted knapweed), a deeply and profusely rooting perennial plant, frequently taller than 1 m. Site preparation and site maintenance in 1979 and 1980 were the same as on the 5-year-old sites. {Survival in 1982 was ”8l%. .Site 6 (Logan 24) is a MWD Perrington clay loam. Formed from a loamy glacial till, this soil had been severely eroded due to logging in the early 1900's and subsequent agricultural activity. The original soil surface was loam but repeated cultivation left topsoil bare of cover and subject to severe wind erosion. The result was a clay loam surface which is the former upper B horizon. Surface soil pH was 6.9 due to the high Ca content of the limestone parent material. Organic matter was 3% in 1982 and both P and K were rated deficient for the previous corn crop. Both surface and subsoil were severely compacted on Site 6. Infiltration of moisture in the clay loam surface was restricted to a mosiac of deep cracks which resulted from ponding and puddling (Trouse 1971). Surface channels leading to subsurface horizons were discontinuous, thereby further reducing moisture infiltration (Robertson & Erickson 1978). Free gt a; (1974) reported that soils like this with low organic matter and compaction have greatly reduced infiltration. Bulk density of the clay loam Ap was 1.5 gm/cm33 it was 1.8 gm/cm3 at 40 and 60 cm in silty clay loam and clay. Mean 4-year height growth was between 4.3 and 5.0 m, significantly different (P20.05) 42 from Site 5 which was sandier but in the same drainage class. vegetation competition on this clay site was the greatest at 3024 kg/ha. Dominant species were annual/perennial grasses with Daucus carota L. (wild carrot) co-dominant. Survival in 1982 was only 63%. Sites With Little or No Productive Potential Site 1 (Springdale 4), an ED Kalkaska sand, was originally forested with good hardwood timber, but current agricultural potential depends on physical site alteration since logging and past agricultural use (veatch 1953). No records were available on previous use so it was categorized as an old abandoned farm. Thirty-five percent of the soil surface was bare and dry weight of competing vegetation in 1982 was 1704 kg/ha. The pH of the surface soil on Site 1 was 4.9. With no previous crop for comparison, both lime and additional P would be recom- mended for any corn or small grain crop. Planting unrooted cuttings during an extended dry season would have been unsuccessful on this site. There are small knobs throughout the 4.9 ha field with storm-washed caps of fine sand from a ridge just to the east. In such sterile soil, small roots would die immediately (Lyford and Wilson 1966). No vegetation except Prunus pennsylvanica, CL.F.) (pin cherry) was found on the caps. A loamy sand surface with medium granular structure and 5.2% organic matter indicated surface soil building, perhaps from past manuring or green cover crops. The site is drouthy, however, with no indication of a water table or even moist soil at 276 cm. Mean 5-year heights were from 3.3 to 4.1 m, significantly different (P:0.05) from all other 1978 plantings. Mean 5-year diameters ranged from 3.2 to 7.4 cm; survival in 1982 was 76%. 43 Site 7 (Riverton 25) is a SWPD Iosco sandy loam and occurs on a glacial till plain. The site was in asparagus production before the planting of hybrid poplar in 1979. Surface soil pH was 5.6 in 1982 and soil nutrient tests showed a deficiency of both P and Mg for asparagus. Mean 4-year height for all three clones was only 3 m, which was signif- icantly less (120.05) than on the other 1978 sites, Sites 5 and 6. Mean 4-year diameter ranged from 1.5 to 2.3 cm and survival in 1982 was 86%. The sandy loam surface on Site 7 had fine granular structure and 3% organic matter. Surface infiltration was good but downward movement rapid to 41 cm. There were mottles between 41 and 87 cm, indicating alternate periods of saturation and aeration at that point. Gleyed colors (blue-gray) below 87 cm identify a reducing (anaerobic) situation throughout the year; rooting was effectively stopped at 87 cm on Site 7. vegetation competition was 2637 kg/ha, with D, gargta and annual/peren- nial grasses dominant on the site. Packaging Corporation records show repeated cultivation between rows was needed during the first growing season, indicating severe weed problems. Sites 8 and 9, planted in 1978, are part of the same field and are not recommended for hybrid poplar culture under any circumstances. Site 8 (Maple Grove 29) is a SWPD Finch sand formed on an outwash plain with a strongly cemented subsoil (ortstein). The sandy loam surface had only 2.8% organic matter and a pH of 4.5. The upper part of the subsoil was a bright orange, cemented sand with mottles indicating reduced drainage. The lower part was a dark reddish, mottled cemented sand. The water table was at or near the soil surface in spring and early summer (May and June) due to slow permeability through the cemented sand. Once drained, however, the coarse acid sand (to a depth greater than 174 cm) had little or no moisture holding capacity, leading to excessive [4.1+ dryness. The ortstein layer is a complete impediment to roots; none were visible at 26 cm or below. Natural soil fertility was very low in this soil and P and Mg were deficient for corn or small grains. Mean 5-year height growth was 3 m for Pop. X and NE 47. Growth for Pop. X was significantly lower (P20.05) than on the other 5-year sites whereas NE 47 performed the same on Site 8 as on Site 1. The same site pre- paration and first- and second-year maintenance used on Sites 1-4 was used on Site 8; understory weed competition in 1982 was a light 1923 kg/ha. Dominant weed species were annual/perennial grasses with Solidago pp. dominant, and some m pp. (raspberry) among and within tree rows. Site 9 (Maple Grove 29), a Lacota organic soil, is an example of PD, low depressional areas that frequently occur on outwash plains that are already poorly drained. No hybrid poplar plantations of substantial size were planted by PCA on this soil/site condition. An effort was made in 1978, however, to hand plant poplars on such areas within existing vegetation, which was usually §alixmgp. (willow), §g§g§_§2. (sedge) and Typha latifolia (L.) (cattail). The soil on Site 9 was a mucky loam with 15% organic matter. Bulk density of the surface horizon was only 0.9 gin/Cm3 due to its highly fibrous structure. A gleyed clay loam occurred under the surface loam at 15 cm, stopping root expansion at that point. The water table was above ground level for all but 5 weeks of the 1982 growing season with the lowest point observed only 15 cm from the surface. Only Rpx survived (about 25%) on Site 1 but mean 5-year height was only 2.3 m. 45 Pest Incidence An evaluation of hybrid poplar under intensive culture cannot be made without considering the effects of pests (insect, disease and mammals). Disease and insect problems may be especially severe when introducing exotic hybrids like these poplar cultivars into new regions in a monoculture situation (Dickmann & Stuart 1983). with the assistance of the North Central Forest Experiment Station and the Department of Forestry at Iowa State Universitygg a pest census was made of all hybrid poplars measured for 4- and 5-year height growth on eight of the nine productivity research sites (Site 9 was omitted due to its small size and poor survival). Septoria musiva (Peck) was of particular interest because it is the most important pathogen on intensively-cultured hybrid poplar in the North Central Region (0stry & McNabb 1983). This fungus causes necrotic spots on the leaves and cankers on the main stem and branches. Septoria musiva was present on all three clones on the first eight productivity sites evaluated. Pop. X and NE 47 had nearly the same incidence of leaf spot while NE 308 had considerably less. NE 47 has 2, maximowiczii parentage which has been identified as highly susceptible to the Septoria fungus (Dickmann and Stuart 1983). A high incidence of leaf spot on a particular site did not always lead to a high incidence of canker. For example, on Sites 1, 2 and 3 (with 100%:incidence of leaf spot), only Pop. X had cankers. The .exceptions to this relationship were found in the three 1979 plantations. ‘On Site 5, a MWD sandy loam with slightly reduced soil drainage, Pop. x g/Field assistance from Lincoln M. Moore, North Central Forest Experiment Station, East Lansing, MI and Peter Gerstenberger, Department of Forestry, Iowa State University, Ames, IA. 46 land NE 47 had nearly 100% leaf spot infection with 22% of the trees fcankered. Site 6, a MWD heavy clay site, had a high incidence of leaf spot on.Pop. X and NE 47 (87 and 97%) and over one half of the 30 trees sampled were cankered. Site 6 has a seriously compacted soil surface which limits surface infiltration of soil moisture and movement of 02. On Site 7, a SWPD sandy loam with a gleyed subsurface soil, Pop. X had 82% incidence of leaf spot and 23% of the trees were cankered. Marssonina brunea (E11. and En.) P. Magn. was found on all research sites evaluated. NE 47, with the highest incidence of S. musiva, had the lowest incidence of M, brunea_of the three clones. The §!.EEEESE fungus infests leaves, petioles and succulent shoots. Serious M. m defoliation has been observed in the southern United States on Populus deltoides (eastern cottonwood) and the disease has proved to be devastating to susceptible poplars in Europe (Dickmann and Stuart 1983). Venturia sp. was only found on the 1979 VD to ED sites (with the exception of one tree on Site 8, a SWPD ortstein soil that is very droughty after water drains through the cemented subsoil). Venturia was the lowest on Pop. x (3%), low on NE 47 (307%) and the highest on NE 308 (10-27%). Symptoms first appear in May on leaves near shoots infected the previous season. Infected leaves become curled, distorted and blackish green; the shoots turn black, brittle and curl to resemble a "shepherds crook". Death of the terminal and lateral shoots can distort the form of a tree causing shrubby growth. Melampsora medusae (Thum) did not occur on any of the trees evaluated on Sites 1-8. Larix laricina (Du Roi) K. Koch (tamarack) is considered the important alternate host for this poplar rust and is not an abundant tree near PCA plantations. 47 Saperda inornata (SAY), poplar-gall saperda, attacks the stems and branches of native and hybrid Populus. Calls caused by this insect were observed on all sites evaluated except Site 7, the SWPD sandy loam with a gleyed subsoil. Site 8, a SWPD sand with ortstein subsoil, had 43% occurrence of galls on both Pop. X and NE 47. Site 6, which also had a high incidence of S, musiva_canker, had.more galls than on Site 5, both planted in 1979. On Site 1, the ED Kalkaska sand, all three clones had galls. Moore (1984) concluded that poplar-gall saperda does not appear to be a threat to young trees if there is less than 8 galls per tree; however, further research is needed with different Populus clones~ under variable growing conditions before real impact of this pest can be determined. Cryptorhynchus lapathi (L.), the poplar-and-willow borer, is an important pest of young sapling and pole-size hybrid poplar. Heavy attacks by this weevil can cause growth loss, stem breakage, tree deformity and mortality. Trees become heavily attaCked within 30 cm of the base, and as trees become older and diameter and height increase, the level of attack by the insect increases. Cryptorhynchus lapathibap E was observed most frequently on Pop. X and NE 47 (33 and 12%) on Site 8,w%: the cemented ortstein soil. There was minor occurrence on three other/1 sites. Prodiplasis morrisi (Gagne), the leaf roll midge, is an impor- tant pest of Populus species in North America, especially in hybrid poplar plantations and nurseries in southern Canada (Dickmann and Stuart 1983). It has also been identified in plantations in northern Michigan in 1979 (Morris 1981). The larve feed in the tightly rolled blade tissues of leaves newly emerged from terminal tips of young trees. The leaf veins and tissues are then damaged and the leaf fails to unrOll and develop normally. Defoliation during the second and third year reduces 48 height growth and late-season midge infestations can stunt the terminal leaders which become over-topped by lateral branches. The resulting forks reduce tree quality and value. Prodiplasis morrisi occurred on only three sites but with considerable intensity. On Site 6, NE 308 was 90% infected and NE 47, 83%. On Site 5, NE 308 had 33% affected trees and NE 47 had 62%. On Site 8, 62% of NE 47 were affected. A summary of pathogen and insect incidence based on 210 trees of each clone measured on all eight research sites is shown in Figure 5. NE 47 had the highest incidence of §, mggiza leaf spot and canker and §, inornata, both affecting main stem and branches. NE 47 had the least incidence of M. m. However, Pop. X had a high incidence of M. .brggga and §, EEEEXE leaf spot but was heavily cankered by §J.EE§$X§! NE 308 had a high incidence of M. brggga_and had the highest incidence of P. morrisi. NE 308 had the lowest incidence of both Septoria leaf spot and canker. CONCLUSIONS Analysis of 4- and 5-year height growth of hybrid poplar grown under cultivation plus herbicide culture showed growth was significantly decreased (P20.05) on sites other than the most optimum for high-value agricultural crops. This does not mean that only the most optimum growth is acceptable. Height growth and woody biomass production on all but the poorest sites may be considered acceptable, depending on management objectives and economic considerations. Natural soil drainage is the most important factor to consider when selecting potential sites for hybrid poplar production. Soil texture within drainage class can either increase or decrease productivity. Figure 5. Percentage of total trees per clone sampled on eight research sites infected with a major pathogen or insect pest in August, 1982. Field evaluation assisted by North Central Forest Experiment Station and Iowa State University; data prepared by the author. 49 boson 32:? 2.93 uoozo one doe—coo morocco 02...... «one 30. one EEO.— Eamon. oscugfoucro \ \. vac. utho> wisdom =cu .530.“— =2 3a.. atouoom comma 2.3.302: 9:23: Sacco... _oEoE 2.2:: o...3:o> utoudom ousocom o_no_a=oo..d atoacom \I\I.\. V non m2 m .3 m: x .dod L «on» 30. «5:03.55. mwOw ms fl .. u\ 2 me m“ H m“... 50 As natural soil drainage is reduced and soil texture becomes heavier than sandy loam, several factors interact which negatively affect productivity. These factors include reduced soil aeration, soil compaction, and heavier competition from deeply and profusely-rooting biennial and perennial herbaceous weeds and grasses. On sandy sites with excessive natural soil drainage, low available soil moisture and soil nutrients are the most important detrimental factors. well-drained sandy loam and loamy sand soils will contribute to excellent hybrid poplar production when optimal planting, site preparation and weed control techniques are used. Somewhat excessively drained soils have good productivity potential only if there is banding or sandy loam texture between 75 and 200 cm. Stoniness greater than 3% is detrimental in a SWED soil. Moderately well-drained soils with reduced drainage, usually caused by a heavy clay layer from 50 to 100 cm, have good productivity potential depending on soil texture throughout the soil profile. In a loamy sand or sandy loam with no ortstein layer, reduced drainage at 75-100 cm could benefit tree growth by slowing downward percolation and forming a temporarily perched water table, thereby adding to soil moisture availability. If reduced drainage is caused by a plow pan just under the Ap horizon or by compacted soil layers, sub- soiling may improve the situation and raise the productivity potential, although this may be temporary. Realizing the potential productivity of SWPD soils requires some form of mechanical site alteration that may or may not fall within budget constraints. All SWPD soils have restricted internal soil drainage between 15 and 100 cm. Some form of ditching will be required to maintain 51 consistent drainage to l m, the major tree rooting depth (Luthin 1951)., Bedding may be an alternative to ditching if drainage is natural to at least 60 cm. If plow pans and/or compacted layers are causing reduced drainage, subsoiling may alleviate the problem. Poorly drained soils need extensive ditching and may present soil fertility problems once drained. very poorly drained soils, as well as ED soils, should not be considered for hybrid poplar culture. Only those hybrid clones which are shown to be resistant to insect and disease pests, particularly §, mggiza leaf spot and canker, should be considered for planting. Use of only the finest-quality planting stock, using utmost care in handling live planting material, and maintaining good weed control both in the year of establishment and in the second year are all essential to getting the most from those sites with the best soil/site productivity. 52 Baker, James B. and W.M. Broadfoot. 1978. A new technique of site selection for hardwoods. So. J. Appl. For. 2:42-43. Dickmann, Donald I. and Katherine W. Stuart. 1983. The Culture of Poplars in Eastern North America. Michigan State University, East Lansing, MI 488245 168 p. ' Jones, A.R.C. and J. Grant. 1983. Hybrid poplars or hardwood coppice? An agriforestry option to economically increasing wood production in Eastern Canada. For. Chron. 59:143-145. Kreighton, Dean M. 1975. Soil changes after hay meadow abandonment in southwestern Wisconsin. USDA For. Serv. Res. Pap. NC-l46. 6 p. Lull, Howard, 1959. Soil compaction on forest and rangelands. USDA For. Serv. Misc. Pub. 33 p. /Luthin, James N. 1957. Drainage of Agricultural Lands. American Society of Agronomy, Monograph #7. American Society of Agronomy, Madison, WI. p. 461-578. Lyford, W.H. and B.F. Wilson. 1966. Controlled growth of forest tree roots: techniques and application. Harvard For. Pap. #16. 12 p. McKibben, E.G. 1971. The soil compaction process. In: Compaction of Agricultural Soils. ASAE Monograph, Am. Soc. Agr. Eng.. St. Joseph, MI 49085. P. 29-56 Miller, D.E. and W.H. Gardner. 1962. Water infiltration into stratified soil. Soil Sci. Soc. Amer. Proc. 26:115-119. Moore, Lincoln M. 1984. The major insects and diseases affecting intensively-grown hybrid poplar on Packaging Corporation of America lands in central Lower Michigan. Unpublished Ph.D dissertation. Department of Forestry, Michigan State University, East Lansing, MI 48824. 157 p. Portas, C.A.M. and H.M. Taylor. 1976. Root growth in dry soil. Soil Sci. 121:170- 175. Pritchett, W.L. and W.H. Smith. 1974. Management of wet savanna soils for pine production. Fla. Agr. Exp. Sta. Tech. Bull. 762. 22 p. Pritchett, William L. 1979. Properties and Management of Forest Soils. John Wiley and Sons, Inc. New York. 500 p. Robertson, L.S. and A.E. Erickson. 1978. Soil compaction: symptoms, causes and remedies. Crops & Soils, Jan., p. 13-16 & Feb., 12-15. Russell, R. Scott. 1977. Plant Root Systems: Their Function & Interaction with The Soil. McGraw-Hill Book Co. (UK) Limited, London. 298 p. 53 Trouse, Albert C. Jr. 1971. Soil conditions as they affect plant establishment, root development and yield. In: Compaction of Agricultural Soil. ASAE Monograph, Am. Soc. Agron. Eng., St 0 Joseph ’ MI “’90 85 o P o 122-114’9 . Veatch, J.O. 1953. Soils and Land of Michigan. The Michigan State College Press, East Lansing, MI 241. p. White, E.H. and w. L. Pritchett. 1970. Water-table control and fertilization for pine production in the flatwoods. Fla. Agr. Exp. Sta. Tech. Bull. 743. 41 p. Woods, Ruth F., Lincoln M. Moore, Louis F. Wilson, Michael E. Ostry and Donald 1. Dickmann. 1982. Performance of 3-year old hybrid poplar clones on glacial soils in Lower Michigan. In: Seventh North American Forest Biology Workshop: Ed: Bart A. Thielges. July 26-28, 1982. Univ. of KY, Lexington, KY. p. 417-422. Woods, Ruth F. and James W. Hanover. 1982. Growth of Imperial Carolina Poplar over a range of soil types in Lower Michigan. Tree Planters Notes 33(2)8-13. CHAPTER III TWO-YEAR HEIGHT GROWTH OF THREE HYBRID POPLAR CLONES USING NO-TILL CULTURE ON OLD FARM FIELDS 55 INTRODUCTION "No-till" has been defined as "placing the crop seed or seed transplant into the soil through the sod or previous crop residue by means of a trench or slot". No other soil manipulation is required (Crosson 1981). In this report, unrooted cuttings of hybrid poplar were planted using no-till in the spring of 1981 by Packaging Corporation of America (PCA) near Manistee, Michigan. The technique was adopted by PCA to simplify site preparation and maintance in their intensively-cultured hybrid poplar plantations. While no-till is becoming widely accepted in agriculture, it has not been widely used in poplar culture. Most research in recent literature involves conventional tillage with banded or broadcast herbicide application (s) or tillage with mowing or cultivation (Schreiner 1954, Arid 1962, Zsuffa 1977, Brissett at El 1979, Demeritt 1981, Raitanen 1983 and Hansen et_al 1983) for site preparation and subsequent weed control. The objective of this study was to determine growth of three hybrid clones under intensive culture where herbicides were used exclusively in site preparation as well as first- and second-year weed control. The efficacy of herbicides are known to be affected by soil properties (Crosson 1981), target and crop plants, weather and correct timing of application based on growth habit of the plants (Meggitt & Kells 1984). To test the efficacy of herbicides used in this study, composition and dry biomass of understory vegetation at the height of the 1982 growing season were determined. Sites with the most potential for poplar growth using no-till are identified and suggestions are made for tailoring herbicide use to fit various site conditions. “5" ivy-v- . . pat-v “3.14. New: "'§- .4 ‘4- . to. 3.: U‘ I / 56 METHODS Site Selection Six sites were chosen to evaluate height growth of hybrid poplar under no-till chemical management. Five of the six sites were classified according to USDA Soil Conservation Service (SCS) natural soil drainage (NSD) classes. The sixth site had been altered by parallel drainage ditches which ran across the 16.2 ha field and emptied into a collection ditch along a county road. This last site gave the opportunity to investigate a range of altered soil drainage (ASD) conditions by analyzing seven "sub-sites" on the same field. Each of the six sites were mapped for soil variation by taking soil borings every 30 m on transects 30 m across the plantings. Surface soil texture, color of and depth to mottles and base soil color were determined in the field giving tenative SCS soil series. Areas within the first five sites with NSD which varied significantly from the dominant texture and drainage were mapped out and not used. Boundaries were drawn for homogeneous areas of from 2 to 4.5 ha. The 16.2 ha site with ASD was mapped in the same way, and seven sub-sites (from 2 to 8 ha) were identified. On these sub-sites, soil borings were taken along transects in July, 1982, November, 1982 and February, 1983 which gave depth to the seasonal high water table. These data, along with soil texture, color and mottles gave an estimate of ASD. Soil/Site Analysis One soil profile description was done on each site with NSD, and one on each sub-site with ASD. Soil horizons were described down to 0a- J..- u 'IAF‘ 0.0.. : rt 1: "v do 1..” I“) .T a at... 57 154 to 240 cm, depending on depth from the soil surface to the parent material or C horizon. Samples were taken from each horizon and sent to the Michigan State University (MSU) Soil Test Laboratory in East Lansing, MI for determination of percentage sand, silt and clay. Current SCS soil series were then identified. Soil analysis was also done by the MSU Soil Test Laboratory for P, K, Ca, Mg, pH and organic matter on each site and sub-site. Soil bulk density at 20, 40 and 60 cm was also determined for each site and sub-site. Two-year Tree Height Analysis Ten trees were randomly selected from each clone (which were planted in homogeneous blocks) and measured for first- and second- year height growth in October, 1982. First-year height growth of the trees planted as unrooted cuttings was easily determined from the location of the bud scale scars on the main stem. Tree diameters were not measured in this study, but diameter and height of several poplar clones growing across a range of sites was highly correlated (r2=0.74) in a previous study (Chapter II). The three clones measured were (1) E. x euramericana cv. Raverdeau (Raverdeau), (2) P, Miggé var. charkowiensis x P. EESEE var. caudina (NE 19) and (3) P. x euramericana cv. Eugenii (Carolina Poplar or DN 34). NE 19 was measured on four sites with NSD, DN 34 was measured on three sites with NSD and Raverdeau on seven sub-sites with ASD. Soil textures ranged from the driest loamy sand to an organic muck soil. The data were analyzed using standard ANOVA proceedures and StudentaNewman-Keuls test. Understory Vegetation Competition No vegetation analysis was done in 1981, the year of establishment, so evaluation of the need for second-year chemical weed control became 58 the objective. Site preparation/weed control in the year of establish- ment included a previous year, late October (1980) broadcast application on each site of glyphosate at 2.2 l/ha to control biennial and perennial herbaceous weeds and perennial grasses. Simazine was then applied at 2.8 kg/ha prior to planting in early May of 1981. If an acceptable weed kill was not achieved the previous fall, glyphosate was applied with Simazine in the spring application. The second-year application for weed control was made during the second week of July (1982) using Simazine (2.8 kg/ha) plus paraquat (2.3 l/ha) on all sites except Site 1, Custer 34a. To test the effectiveness of the same rate of Simazine plus paraquat applied over several different soil drainage and texture conditions, 20 circular plots (0.05 mg) were randomly located on each site during the last week of April, 1982. Species name, frequency of occurrence and growth habit were recorded on all plots each month (May through August) to determine species succession and percent ground cover throughout the growing season. All vegetation was clipped in the plots in late August, dried and weighed to determine biomass of understory weed competition. RESULTS AND DISCUSSION NE 19 2-Year Growth Two-year height growth of NE 19 was significantly different (330.05) over the four sites on which it was planted (Figure 6-A). Best height growth occurred on Site 1 (Custer 34). a well-drained (WD) Emmet sandy loam (Table 1). This soil/site condition was also the most optimum for 4-year height growth of three hybrid poplar cultivars shown Figure 6. Influence of natural soil drainage and soil texture on l-year (cross-hatched bar) and 2-year (black bar) height growth of hybrid poplar cultivars NE 19 (A) and DN 34 (B). Bars not sharing a common lower case letter are significantly different (P:0.01) for 2-year growth. sl=sandy loam, scl=sandy clay loam, cl=clay loam. WD=well-drained, MWD=moderately well drained, SWPD=somewhat poorly drained. PCA used township and section to identify plantation sites; eg. Custer Township, Section 34. Both Sites 1 and 2 are on Custer 34; the same applies to Sherman 10 a and b. 59 A Average Height 01:), NE 19 Site 1 Site 2 Site 3 Site 4 Custer 34a Custer 34!: Sherman 10a Sherman 10b W0.el WD,scl MWD,eI SWPD,scl Average Helght (m), DN 34 4 Site 1 Site ‘2 Site 5 Custer 34a Custer 34b Sherman 23 WD,e| WD,scl SWPD,cl SOIL DRAINAGE AND TEXTURE CLASS 6C) Table 9. Soil/site factors l”/ai‘fecting l- and 2-year height growth of hybrid poplar cultivars NE 19 and DN 31+. vegetative Competition :ZOcn After :ZOcn Bulk :“Ocn Natural Spraying in Site Soil :hOon Den. :60on Soil Year-2 No. Text. :60 on (gm/on3) Drainage (kg/ha) Clone 1. Custer 3432/ 51 1.3 :m 3313 3/ NE 19 31 1.3 BR 34 sol 1.3 2. Custer 3hb sol 1.3 ED 2420 RE 19 sol 1.3 EN 34!- 3C]. 103 3. Shem-ran 10a 51 1.11- 21363 2001 235‘. 19 s 1.6 $1 1.3 1+. Shaman 10b sol 1. 5 SIP!) 215“» "E 19 sol 1.? sol 1.9 5. Sher-nan 23 cl 1.? SW” 25“ 3'" 3“ o 1.8 C 1e9 / 2’slzsandy loam, sol-sandy clay loam, cl=clay loan, c-olay HD-well-drained, MWD-moderately well-drained, SHPD=soneHhat poorly drained 3/S'.te l was not sprayed in the second year due to light germination and 31‘0ch Of Weedse z/SCA identified their plantation sites by using township name and section number: e.g. Custer Township and Section 34. Both Site 1 and 2 were on Custer 34, hence a and b. The same applies to Sherman lo. 61 in Chapter II. The field in this study hadeeen in no-till corn pro- duction for two to three years prior to planting poplar in 1981. Soil nutrients were well above the requirements for corn, while surface soil pH was 5.5. Bulk density was 1.3 gm/cm3 throughout the profile and there was a fine granular structure from the surface to 103 cm with an easily penetrable consistency. In sandy loam soils such as this, bulk density can be considered non-limiting between 1.2 to 1.7 gm/cm3 (Trouse 1971). Soil profile horizons alternated in texture between sandy loam, loamy sand and sandy clay loam, with additions of fine gravel at various depths. This banding contributes to additional soil moisture-holding capacity and nutrient availability within the tree rooting zone (Pritchett 1979). Mean Zeyear height growth on Site 1 was 3.8 m, with some trees as tall as 5.0 m. Survival in year two was 99%. While no other compari- sons are available in the literature for 2-year height growth with no- till culture, NE 19 was ranked in the top 15 clones out of 40 in a 4-year clonal trial in the same geographic area (Chapter 1); four-year height growth for NE 19 was 6.6 m on a moderately well-drained (MWD) loam soil. Demeritt (1981) ranked NE 19 as one of the 12 tallest clones in a 4-year study in the Northeast, with heights of 7.5 m and 6.0 m at two different sites. NE 19 was also included in clonal trials in northern Wisconsin but was found unsuitable for plantings due to frost susceptibility (Hansen and Phipps 1981). This cultivar continues growth and does not drop leaves until mid- to late-October in the geographic area of the present study. Site 1 was not sprayed (exception to other 12 sites) with herbicides in the second year (1982) due to what appeared to be a "light 62 weed germination and growth" in June l/. Understory weed biomass in late August, however, was 3113 kg/ha, with only 3% of the soil surface free from current-season weeds. Both annual and perennial grasses were dominant, with Oenothera biennis (L.) (common evening primrose) co- dominant. The question can then be raised, "does the amount of uncontrolled weed competition found on Site 1 towards the end of the second year affect tree growth and if so to what extent?". Raitanen (1978) reported that rhizomous grasses were extremely efficient com- petitiors for water during early establishment and growth of hybrid poplars. Schreiner (1945) found sod and weeds (particularly sod) seriously inhibiting to establishment and growth of hybrid poplars, as did Shipman (1974). With an average 2-year height of 3.8 m, trees in the present study were well above the understory competition, yet the potential for greater growth if_this understory had been controlled cannot be ignored. Site 2 (Custer 34b) is adjacent to Site 1 (on the back side of a south-facing slope) and is a degraded Nester loam. The current soil surface (Ap horizon or depth of plow layer) is the former sandy clay loam upper B horizon (subsoil), a result of wind and overland flow erosion. Structure is moderate angular blocky and the consistency (affecting root penetrability) is firm. Bulk density was 1.3 Sin/cm3 at 20 and 40 cm but was l.# at 60 cm. Trouse (1971) found a dry bulk density of 1.4 to 1.6 gm/cm3 a severe limiting factor in loans, silts and clays; bulk density of l.h at 60 on may have negatively ;/ Personal communication, Tony Pappas, PCA technican, Manistee, Michigan. h ‘7‘! b.\ .w :2“ Si 63 affected root function and growth at this site, however. Soil nutrient analysis showed the site deficient in P for corn, the previous crop, with a soil pH of 5.4. Mean 2+year height on Site 2 was 3.0 m, a significant drop (P:0.05) from height growth on adjacent Site 1. Survival in year two was 95%. Both Site 1 and 2 are WD, with soil texture being the most important factor contributing to differences in height between sites. Site 2 is a sandy clay loam in all horizons from the surface to 215 cm. The soil surface horizon (Ap) is only 13 cm deep underlain by a B/C horizon to 62 cm, with a massive structure impenetrable to tree roots. Thus, the "effective growing space" of Site 2 extended only 60 cm below the soil surface. There was no such limitation on Site 1. Dominant weed species on Site 2 after spraying were the perennials 4gropyron repens (L.) (quaokgrass) and Q. biennis, which was present in both the sexual stage (seed heads) from the previous year (1981) and the vegetative stage (rozette) from the current year (1982). Site 3 dropped one soil drainage class to MWD, and mean 2-year height growth of 2.0 m was significantly different (P:0.05) from both Site 1 and 2. The soil is an AuGres sandy loam.and was consistently that soil texture to a depth of 192 cm, where the C horizon or parent material begins. Bright mottles (7.5 YR 5/8) at 51 cm indicated reduced internal soil drainage when the natural water table is at its seasonal high during the early part of the growing season. Root development in wet, saturated soils is greatly affected by a lowered oxygen content and a subsequent rise in CO concentration (Russell 1961). 2 Soil nutrient status was adequate for the hay which was produced for several years prior to planting hybrid poplar. Understory weed bio- mass was 2002 kg/ha, primarily g, repgns which was not controlled by the 64 July application of Simazine and paraquat. Paraquat, a contact her- bicide, burned back growth present at the time of spraying, but the grass regrew from underground rhizomes to 1.2 m (nearly the height of some trees). The slope and aspect of the planting apparently affected the trees as well as the soil and weed competition. NE 19 is known to be susceptible to frost damage and is growing, here, on a north-facing 10% slope leading into a low, depressional area. Frost damage (considerable dieback of terminals and upper laterals) was observed in the spring of 1982, and survival by that time was 87%. This damage must be considered when analyzing 2-year growth on this site. Mean Z-year height growth on Site U was only 0.9 m, significantly different (£10.05) from the other three sites. Survival was only 62%. Most of the trees sampled grew only 0.3 m in 1981, the year of estab- lishment, and little more in 19820 The soil is a Sims somewhat poorly drained (SWPD) sandy clay loam throughout the profile. The sm‘face (Ap) was only 21 cm deep with a pH of 5.8 and organic matter content of 8.2%. Below 21 cm the base soil color was blue-gray (gleyed) indicating saturated conditions for long periods of time. Bright mottles (7A YR 5/6) from 21 to 60 cm showed intermittent periods of saturation/aeration due to a fluctuating water table. Bulk density of the surface soil was 1.5 gm/cm3 but increased to 1.7 at 40 cm and 1.9 at 60 cm, indicating subsoil compaction. No tree roots were observed below 21 cm. Understory weed biomass was 215# kg/ha. Conyza canadensis (L.) Cronq. (horseweed), an annual, 2, EEEEEE (biennial), Taxaraoum offinale (Weber) (common dandelion, perennial) and Cirsium arvense (L.) (Canada thistle, perennial) were the major weeds. The simazine/paraquat mix sprayed the first week of July was obviously ineffective on this site. Simazine 65 is readily adsorbed by clay and organic matter, reducing the activity of the chemical. The sandy clay loam texture and 8.2% organic matter on this site were important factors influencing the ineffectiveness of the herbicide. The Simazine (Princep 80W, Ciba-Geigy) label recom- mends increasing the rate of application on soils higher in clay and organic matter, but this was not done on this site. Competition between the poplars and the vigorous-rooting annual, biennial and perennial weeds, plus a very limited effective growing space due to reduced internal soil aeration and severe subsoil compaction were strong factors that contributed to the poor one- and two-year height growth of NE 19 on Site 4. DN 34 2-Year Growth DN 34 showed significant differences (330.05) in 2-year height growth on three sites (Figure 6-3). Sites 1 and 2 (Table 9) were previously described in the NE 19 discussion. DN 34 and NE 19 were planted in alternate rows on these two sites. On Site 1, the ND Emmet sandy loam, DN 34 had a mean 2-year height of 3.4 m and survival of 98%. Growth in both years one and two was almost equal to that of NE 19. Although vegetative competition was considerable (3313 kg/ha), DN 34 was well above the height of the understory competition, with some trees as tall as 4.5 m. DN 34 was in the top-ranked 15 clones of a clonal test planted under a tillage plus herbicide system on a WD Nester loam very similiar to Site 2; four-year height growth was 5.7 m. Woods and Hanover (1982) reported that DN 34 had exceptional growth when planted in agricultural windbreaks using complete tillage plus herbicides; two-year height growth on an Emmet sandy loam (same soil series as 66 Site 1) was 4.3 m. Five-year height growth on a sandy loam in northern Wisconsin was 5.6 m with only 66% survival (Hansen g _a_l 1983), but in northern Wisconsin it is considerably harsher than along the east shore of Lake Michigan where the Woods and Hanover (1982) studies were done. On Site 2 (also Site 2 for NE 19), a WD, severely eroded loam soil with a sandy clay loam Ap, DN 34 mean 2-year height was 2.9 m with 99% survival. This was a significant reduction in height from Site 1, due, primarily, to the loss by erosion of the original Ap, the sandy clay loam texture throughout the soil profile, and heavy vegetation com- petition. Site 5 (Sherman 23) is a SWPD Kawkawlin clay loam with a heavy clay subsoil. The water table at 92 cm (seasonal highest point) does not indicate seriously wet conditions. In fact, if the water table were 2.6 cm lower, drainage would have been classed as moderate (MWD). The site had an eroded, compacted surface soil and a heavily compacted sub- surface soil (bulk densities of 1.8 gm/cm3 at 20, 40 and 60 cm). Vege- tation competition was 2541 kg/ha, primarily g. pppgn_s and _D_. m which were not controlled by the second-year spray application. Mean 2- year height growth was 1.7 m with 80% survival. Surface soil erosion, heavy surface and subsoil compaction and heavy vegetation competition were all factors contributing to height growth which was only one half that of Sites 1 and 2. fiaverdeau 2-Year Growth The Raverdeau clone was analyzed over seven different sites with ASD and three different SCS soil series (Table 10.) Best 2-year height growth 67 Table Mi Soil/site factors l/a.ffeoting 1- and 2-year height growth of hybrid poplar cultivar Raverdeau on 6 sub-sites in Sherman Township, Section 10 (Sherman 10), with altered soil drainage (ASD). Depth Vegetative :20om Soil From Organic Competition :20om :40oa Drainage Soil Surface Hatter' After Spraying Site Soil :40cm :60om ter To Water In Soil in Yeartz No. Text. :60 cm (gn/om3) Alteration Table (on) Surface (5) (kg/ha) 6-1 ls 1.5 RD 245 2.6 2002 31 1.5 5 105 6-2 1 1.4 MWD 108 9.3 1515 cl 1.3 s1 1.9 5.3.. Ci 1.5 in) 108 6.3 1639 C1 107 sol 1.3 6.4 sol 0.9 :/ SWPD 45 14.8 1956 sol 1.7 ~ cl --- 6-5 fibrous 0.9 PD 15 12.5 1815 all --- sil --- 6-6 cl 1.7 PD 15 10.8 1794 sol --- 31 --- 6-7 fibrous 0.9 VPD 0 28.3 1926 siol --- sic --- :/s=sand, ls=loany sand, sl=sandy loam, l-loam, sol-sandy clay loam, cl-olay loam, o-olay, sil=silty loan, sicl=silty clay loam. :mswell-drained, WDBmoderately well-drained, SWPDasonewhat poorly drained, Pszoorly drained, VPD-very poorly drained. 6 i/Bulk density could not be measured because soil was in suspension due to water table. 68 (2.8 m with 95% survival) (Figure 7) occurred on Subnsite 6-1, a previously SWPD Menominee loamy sand which was improved to WD through ditching. The former hay field had excellent internal soil drainage with enough sandy clay loam and sandy loam (plus fine gravel) between 60 to 192 cm to hold sufficient moisture. Surface soil pH was 5.9 and no additions of nutrients were recommended. Bulk density was 1.5 gm/cm3 at 20, 40 and 60 cm. vegetation competition (2002 kg/ha) on Subnsite 6-1 was primarily g. repgns. The grass was severely injured from the July application of paraquat, but new growth from rhizomes appeared less than one month after treatment. Sub-sites 6-2, 6-3, 6-4 and 6-6 occurred on the same SCS soil series (Sims) and are either loam or clay loam. A Sims soil is normally found on level or depressional areas on till plains or low moraines. Drainage is normally poor or very poor, but this condition had been improved by the randomly-placed ditches. Internal soil drainage decreased from Sub-site 6-2 to 6-6 due to differences in distance from the ditches. Internal soil drainage decreased from Sub-site 6-2 to 6-6 due to differences in distance from the ditches. Agriculturally designed ditch systems allow consistent drainage throughout a field, usually to a depth of 1 m for high-value crops. In this no-till situation, however, those sub-sites nearest the intersection of the field ditches with the roadsode drain had the greatest improvement in drainage. There was a correlation of r=0.6 (P:0.05) between 2eyear height growth and depth to the highest point of the seasonal water table; as the water table rose, tree height diminished. Sub-site 6-4, which showed a mean 2-year height growth of 2.6 m and survival 95%, was an exception. This site had the highest growth among the four Sims sub-sites but Figure 7. Influence of soil texture and altered soil drainage on l-year (cross-hatched bars) and 2-year height (black bars) of hybrid poplar cultivar Raverdeau. Bars not sharing a common lower case letter are significantly different from each other (2:0.05) for 2—year growth. ls=loamy sand, l=loam, cl=clay loam, org.=organic. WD=well- drained, MWD=moderately well-drained, SWPD=somewhat poorly drained, PD=poor1y drained, VPD=very poorly drained. 69 Mean Height (m), Raverdeau- a a. 2.5 b b 2.0 1.5 c c 1'0 — c I -=- _ -—_'= = = = = = 0.5 E g- = E = E E E :=". E :- "’-_—'." -_'-= .=_ _=' E E = E E Site Site Site Site Site Site Site 6-1 6-2 6-3 6-4 6-5 6-6 3-7 WD,!e MWDJ MWD,cI SWPD,cI 90,079, PD,c| VPD,org SOIL DRAINAGE AND TEXTURE CLASS 7O drainage was less than on Sites 6-2 and 6-3. Organic matter content on Subnsite 6-4 was the highest of the Sims sites (14.8%), which would place this soil in an organic (histic) classification if the Ap horizon were deeper. With the water table no higher than 46 cm and the light (bulk density 0.9 gm/CmB), fibrous surface soil of pH 7.2, growing conditions compare with artifically drained (tiled) muck fields used for high-value crops like celery or mint. The light, rich surface was only 31 cm deep, however, and was underlain with a gleyed (anaerobic) silty clay loam with a bulk density of 1.8 gm/cmz. Tree roots in 1982 were contained within the top 31 cm and would most likely be restricted in future years by the compact, stagnant Bgl horizon below the surface. Thus, it is unlikely that the good growth shown on this site during the first two years will continue. Sub-sites 6-5 and 6-7 are Suamico organic soils which were not altered by the ditch system. Sub-site 6-5 was still poorly drained with the water table at 15 cm or slightly below. Height growth during each of the first two years was only 0.6 m. Survival in the second year was 65%. vegetation competition was primarily Phalaris arundinacea (L.) (reed canarygrass) which was 1.5 to 1.8 m tall when sprayed in July with a tank sprayer positioned in the back of a pickup. Vegetation on this sub-site and Sub-site 6-7 was considerably higher than the sprayer boom and led to nonuniform application, usually injuring only the portion of the plant below the boom while the upper part continued to grow and flower. Sub-site 6-7 had the least altered soil drainage and is classed as very poorly drained (VPD). The water level never went below the soil surface during the study period and was above it for all but six weeks during the year (July 15 to September 1, 1982). The organic surface 71 (28% on) was 31 cm deep and underlain by an impenetrable, gleyed IICgl (parent material) horizon. Effective growing space on this sub-site is limited to 31 cm.whgn and if there is enough air available through oxygenated water. Mean 2-year height was 1.3 m, with 7l% survival, but this was the only no-till submsite investigated where 1982 tree growth was less than in 1981, the year of establishment. The 1981 growing season was more favorable on this wet area because of a short, moist spring (during planting) and little or no precipitation in July and August. On the other no-till sites, all clones grew more, some up to four times more, in 1982 than in 1981. The 1982 growing season was clearly a wet year, with consistent, light precipitation from May through September, and a record 4.5 m snowfall during the previous winter of 1981. While reductions in both NSD and ASD, increases in clay and silt and increased soil compaction clearly reduced poplar height growth in this study, weed competition was also an important factor. It is impossible to assess the effectiveness of the fall, 1980 and spring, 1981 chemical site preparation because no follow-up measurements or observations were recorded. In a separate study conducted by PCA technicans during the summer of 1982, two paired transects were used to determine weed biomass and species composition before and after spraying in July of the second year. Only 28 to 49% of the weeds killed when the same rate of simazine and paraquat was sprayed over all soil textures. The pro-emergent simazine was not effective because germination of annual broadleaf herbs and grasses had already occurred, while paraquat temporarily burned back active growth of biennials and perennials, but they regrew within a month. It is suggested that a 72 previous fall application of simazine applied at a rate tailored to soil texture and organic matter content would carry over into early spring and hold back early germinating annuals. Weed control could then be maintained by applying a lower rate of simazine in a tank mix with 2.3 l/ha of paraquat in June. If application is postponed until July, some vegetation will be as high or higher than the sprayer boom, and the effectiveness of spraying will be reduced. Other herbicides, e.g., the newest generation grass killers such as fluazifop-butyl or sethoxydin, should also be considered and tested for no-till poplar culture. CONCLUSIONS Significant differences among sites in 2-year height growth of hybrid poplar cultivars NE 19, DN 34 and Raverdeau under no-till culture indicate a strong effect of internal soil drainage. Best height growth was achieved on a WD Emmet sandy loam, which was also the best site analyzed for 4-year hybrid poplar productivity under culti- vation plus herbicides culture (Chapter II). The sandy loam soil profile, with narrow bands of sandy clay loam throughout, was ideal and provided the correct balance between internal soil aeration and soil moisture/nutrient availability. The seasonal high water table at 1.8 to 2.4 m from the surface and bulk densities of 1.4 gm/cm3 are also ideal. When soils high in clay and silt (sandy clay loam, silty clay loam, clay loam and clay) are associated with bulk densities of 1.7 gm/cm3 and greater, they can be considered compacted (Lull 1959, McKibben 1971, Chapman 1978). As a result, internal soil aeration is reduced and soil consistency (penetrability) is lessened, limiting 73 or preventing root growth (Hatchell 1970, Trouse 1971, Krieghton 1975, Robertson & Erickson 1978, Barkley, Evers & Raitanen 1983c). When these conditions are combined with reduced internal soil drainage from a seasonally high water table, average yearly height growth and survival of poplars are substantially reduced; e.g., poplar cultivar Raverdeau in the present study. Soils classed as MWD, SWPD and PD with sandy clay loam, silt loam, clay loam or clay textures may be altered to improve productivity of poplar by using an agricultural ditch system designed to consistently lower drainage to l m from the surface. Productivity may then come close to or equal WD soils, if soil compaction is not a problem. Compaction seems to be the case, however, on low-value heavy textured agricultural fields. If this type of land is all that is available, then subsoiling and/or bedding may be done (Pritchett a. Smith 1974, White & Pritchett 1970) if economic considerations will allow it. Very poorly drained soils have little or no potential and should not be considered for hybrid poplar under any circumstances. Arid, P. L. 1962. Fertilization, weed control and the growth of poplar. For. Sci. 8:413-428. Barkley, B.A., H.W. Evers and W.E. Raitanen. 1983. Cultural practices. In: New Forests in Eastern Ontario: Hybrid Poplar. Sci. and Tech. senes’ V01. 1. P. 187.20“. Brisett, J.C., J.W. Hanover, T.J. Stadt and J.W. Hart. 1979. Improved poplars for Michigan through the Michigan State Cooperative Tree Improvement Program. In: Proc. North Am. Poplar Council, 1979, Annual Meeting, Thompsonvill, MI. p. 115-122. Chapman, G.W. & T.G. Allan. l978b. Special techniques for difficult sites. In: Establishment Techniques For Forest Plantations. FAG ForeStI'y Paper #8e Pe 79-120e Crosson, P. 1981. Conservation tillage and conventional tillage: a comparative assessment. Soil Conservation Society of America. Ankem'. Iowa. 35 P0 ' Demeritt, Maurice E. Jr. 1981b. Growth of hybrid poplars in Pennsylvania and Maryland clonal tests. USDA For. Serv. Res. Note. NE-302. 2 p. Hansen, Edward, Lincoln Moore, Danial Netzery Michael Ostry, Howard Phipps and Jaroslav Zavitkowski. 1983. Establishing intensively cultured hybrid poplar plantations for fuel and fiber. USDA For. Serv. Gen. Tech. Rep. NC-78. 25 p. Hatchell, G.E. 1970. Soil compaction and loosening treatments affect loblolly pine growth in pots. USDA For. Serv. Res. Pap. SE-72. 9 P. Kreighton, Dean M. 1975. Soil changes after hay meadow abandonment in southwestern Wisconsin. USDA For. Serv. Res. Pap. NC-l46. 6 p. Lull, Howard. 1959. Soil compaction on forest and rangelands. USDA For. 89”. I'IiSCe Pub. 33 PO McKibben, E.G. 1971. The soil compaction process. In: Compaction of Agricultural Soils. ASAE Monograph, Am. Soc. Agron. Eng., St. Joseph, MI. p. 29-56. Iegett, William F. and Jim Kells. 1984. Weed control guide for field crops. Ext. Bull. E-434. Coop Ext. Serv. Mich. St. Univ. 45 p. Pritchett, William L. 1979. Properties and Management of Forest Soils. John Wiley & Sons, Inc. New York. 500 p. Pritchett, W. L. and W.H. Smith. 1974. Management of wet savanna soils for pine production. Fla. Agr. Exp. Sta. Tech. Bull. 762. 22 p. 75 Raitanen, W.E. 1978. Energy, fibre & food: agriforestry in eastern Ontario. In: Eighth World Forestry Congress, Jakarta, Indonesia. Discussion Area: Forestry For Food. 13 p. Raitanen, W.E., B.A. Barkley and H.W. Evers. 1983b. Setting out the crop. In: New Forests In Eastern Ontario: Hybrid Poplar. Sci. and TBCh. series, V01. 1. P. 133-1%. Robertson, L.S. and A.E. Erickson. 1978. Soil compaction: symptoms, causes and remedies. Crops & Soils, Jan., P. 13-16 and Feb., P 0 12-15 . Russell, R. Scott. 1977. Plant Root Systems: Their Function & Interaction With The Soil. MoGraw-Hill Book Co. (UK) Limited. London. 298 P0 Schreiner, E.J. 1945. How sod affects establishment of hybrid poplar plantations. J. For. 34:412-26. Schreiner, E.J. 1954. Variation between two hybrid poplars in susceptibility to the inhibiting effect of grass and weeds. J. For. 43:669-672. Schreiner, E.J. 1974. Poplars can be bred to order for mini-rotation fiber, timber and veneer production and for amenity plantings. In: Proceedings let Northeastern For. Tree Impv. Con. 21:85-96. Shipman, R.D. 1974. Preparing planting sites with herbicides. Tree Planters Notes. 26:1-4. Trouse, Albert 0., Jr. 1971. Soil conditions as they affect plant establishment, root development and yield. In: Compaction of Agricultural Soils. ASAE Monograph, Am. Soc. Agron. Eng., St. Joseph, MI p. 122-149. White, E.H. and W.L. Pritchett. 1970. Water-table control and fertil- ization for pine production in the flatwoods. “1a. Agr. Exp. Sta. Tech. Bull. 743. 41 p. Zsuffa, L., H.W. Anderson and P. Jaciw. 1977. Trends and prospects in Ontario's poplar plantation management. For. Chron. 53:195-200. CHAPTER IV SITE EVALUATION PROCEDURES FOR INTENSIVE CULTURE OF HYBRID POPLAR ON OLD FIELDS 76 77 INTRODUCTION With hardwood fiber demand expected to increase almost 50% by the year 2,000 (USDA Forest Service 1973), there may be a need to acquire large acreages for intensive culture of promising tree species, including Populus hybrids. Site knowledge, in this case, is imperative. Prime agricultural land in large or small parcels is not available nor affordable for such cultivation, so the increased demand for extensive tree culture may have to be met on sites that are marginal for agri- culture. Such land may require site alteration as well as site preparation for planting, which, although costly, is essential to the maximization of productivity. Studies involving large-scale plantings of hybrid poplar as a source of fast-growing wood fiber in Canada indicate it is essential to make a correct assessment of soil/site factors if rapid annual height growth is expected (Barkley p_t_ pl 1983c, Zsuffa 1983, Zsuffa 1979, Roberts & Khalil 1980). Research on large-scale plantings of hybrid poplar by Packaging Corporation of America (PCA) in northern Lower Michigan showed that soil/site conditions were the most important factors affecting initial establishment and early growth of hybrid poplars (Chapters 1 to 3). An in-depth understanding of site factors gives the tree grower a strong bases for making an intelligent evaluation of a potential planting site. With such knowledge, intensive culture procedures can be tailored to assure high initial survival and rapid early growth. The purpose of this paper is to outline the soil/site factors which affect’ establishment and early growth of hybrid poplar plantings (Tables ll-l3) 78 and present an easy-to-use field guide (Figure 8) for evaluating the potential of agricultural fields for intensive culture of hybrid poplar. Whereas this guide is based on work in northern Lower Michigan, it should be applicable to glaciated areas throughout the Lake States. SOIL/SITE FACTORS AFFECTING HYBRID POPLAR CULTURE Studies with forest species in this country indicate that soil factors are closely related to site quality and productivity (Carmeen 1975). Many of the guidelines for evaluating forest sites cannot be used for agricultural fields, however, as soil texture and fertility factors on these sites can differ greatly from forest sites (Hoover 1949, Wood 1977). Baker and Broadfoot (1978) published a soil/site evaluation guide for sixteen southern hardwood species on non-glaciated forested and agricultural lands. Their field guide was devised subject- ively, then tested statistically using field plot data for the respect- ive hardwoods (Baker and Broadfoot 1977). Although many of the factors in their guide are applicable to fields in Lower Michigan, soil factors, climate and length of growing season in the southern hardwood region are very different from the glaciated area of Michigan. Furthermore, the one Populus species (eastern cottonwood) included in the southern guide has different site requirements and tolerances than the hybrid poplars commonly grown in Michigan. Evaluating currently cropped agricultural or old farm fields in Lower Michigan requires guidelines specific to the local soil/site conditions. Past glacial history has produced soils with tremendous variability per unit of land area (Chapter 1). Native forest species have not occupied these farm lands for more than 50 years, so it is not possible to evaluate site productivity based on former tree cover. 79 Furthermore, early abusive agricultural practices and subsequent surface soil erosion may have seriously altered the soils since logging. Agricultural practices used within the last 5 to 10 years must also be taken into consideration. Crops grown, chemicals used (pesticides, fungicides, herbicides and fertilizers), machine trafficing, and timing of cultivation all contribute to completely different soil/site conditions than one would find on a forested site. To make an accurate and effective soil/Site evaluation of agri- cultural or old farm fields for intensive culture of hybrid poplar, three major factors must be considered: 1. NATURAL SOIL DRAINAGE 2. EFFECTIVE GROWING SPACE 3. SITE HISTORY AND POTENTIAL MANAGEMENT CONCERNS These factors significantly affected performance of young hytrid poplar plantations and field clonal trials planted by PCA in northern Lower Michigan. In the studies reported in Chapters 1 to 3 it was determined that any change in NATURAL SOIL DRAINAGE from optimum, well- drained conditions caused a significant drop in productivity. EFFECTIVE GROWING SPACE, which includes natural soil drainage, is mainly concerned with physical soil properties: texture, structure, consistency, develop- ment, arrangement of profile horizons, and presence or absence of plow pans, cemented layers or layers with high bulk density (soil compaction). SITE HISTORY AND POTENTIAL MANAGEMENT CONCERNS include soil/site effects of cropping and chemical management, as well as potential problems, based on current vegetation on the site being evaluated. NATURAL SOIL DRAINAGE is the most important factor when evaluating fields for potential hybrid poplar plantations (Table 11), and it is free of saturation (or partial saturation) by water from rain, snow, ; nsoaeaeeoo mcawuos o\: cadence noonduo: mcaosoou no so“: near axons zofiaoa eeuozamo: .amam scam across .hmpm .omoopo sodas» uoaevda homo no home .zoaaoh cox“: .cou srwfium card no m.o so omnma neaaaos axons woods mooauaocoo moflaaos anew omcmwo neon: gnome zoaaoh wcaosvou a such: can crops .onHoa no omcmho woonauon .hsum czar .2oHHo» core so or ca no owccwo .omcmho arranm commusmpsn .mAOHoo mono .mnoaoo sexes muoaoo azwanm .eeu prewar axon: hour .aq no n.m noaasos ozone sonar cross ozone cross mama oceano: eeaoaoo crown hour swan seam .SA axon: commune once 0\: no adam run: each: «use. cross rhea hour .pq c030HA rad: roman axons ruse ozonm :zoum axon: knew no .A< mace .HHom confidence mcofiuuocoo wcaozocu common msazoum common wcazoum common wcazoum mcdosoou .oommnsm :4 ooouwsm seem :« ooownsm some madman ooomwzm mgm m cm adzm :3: :3 cram s cm measured coaamoauaacoeH .ocudzoa: more; ca wnHQOA page»; we cascade o>an=oaca now mean o moauooacm ca coauouoeancoo somepoasa shoe one .so<2H<=: oHom neazaonmnmnm .mconum«>onnns annexe» Haom :OHHH: omeom do: morroaq .wmonm .o no an so 0 no no snow :oxcmnm mmOE .oweom do: nonnso can: ponnoo can: annosdwsm o>nmnms no snnu hocmpmdmcoc on on :.dw.am wanmond .ononcsnnm axooam c>nmmos no sndm mm on c.Hw mm zoaasrm hnm> m.m neocwconrn an ac no Hoar onsaoznnm n.m est ma .mnm .n .Hnm on :.Hw.nm axOOHm d< :n H no Hm eonsaxo» omnsoo snowmano Ho .Hon .HMm Ho>mnm mnocncoem concoeoo on :.Hv.qm ocnw Rn ronmonooH none: can: conmncnom canon :edem; an arc» a< noun: ran: can: 0 no 40 on ncounno: o no m wcounno: u scams 0 no run: mcownno: Hm .nH eonm on How no A no m on c an .nnn .m menu a eonnnSmnem annexes .no no centres omoohosn oz hampered AHom Anmwcs no :nmnm camcnm no unoasucocsm no noasconm cone onsnosnnm unopnm can: ozone amnm axons annm roman no on» .czonb n:m«q xnme no honw and: xnme no hmnm xnma noaoo oncdmno .Ho .0 .n Ham .Honn .Hon .mH H .Hm onsaxoe Q< one so: an m can conmono neon conmono on anon no So onw can: 50 cm on OH 20 omM radon d< do onHanoo S; .2 near. 5:: deer or moeznéo Snow Accusesscoom nozv sarong resonu wondered Hmnucoaoa :04 cannons: essnaao sonamonwancoeH .:omn:onz nczog an unnamed cunnaz now moHfiommhm on razndnazoo was» rnoaomm Hdon Heednh;m .NH ranch 83 Samson runner .znaancmnuocom noon on no arrange an no: .moooovmcsn nurse on nofionnnmd anon mo conserve or» com moHonannm macaw conwcsoo mo rename or» .zooonnnncoo adom .meod no mean: .nofionenmd ansecooom anon moaodansd anon ansEnnd mo psosomcmnno .onsposnan Hnow honouo .eooH annouao .smoH ands zuanmuaonw .snoH nanmuann .sooH node hereunder .esoana .soOH anaconda .ezmn nEmOHunH .ocomum .ecom AHHc>snmumnw .mconamn>onpan onauxou Hdom He no Home . c o I or no he in nor a: a 3:. or 5 a; co cé as no :2 5 Sn... or 0 .Ho .Honm .Hnn on m.HM am and road can 30Hd oz Ho>mnm cram Raw snoumnno racewano .H no\£ 0 can: neoconnoou msoscnncooonn meson mo cocononm mmzpannmms no .Inmflsmsspam no cnonm onwcnm o>nnwns no agoofin .nnogsr:o .noaszonu onsuosnam noflauoe moavaoa o: axons no anon can: ozone no mnonnn can: roman meow can: axons cwzmno .xoamoh no :3 6285 arms as sonnon eons. :2 Ewes nonoo 84 Effective growing space would have been :200 cm. As a result of surface erosion, the original Ap is gone on some Nesters and the upper sub- surface B horizon (a heavy clay loam) is now the Ap. The lower B horizons are a severely compacted clay (from trafficing when wet) with high bulk densities. Effective growing space on these sites is only about 30 cm, the depth of the plowed Ap. Surface soil depth is one of the most significant physical soil features affecting hybrid poplar establishment and early growth because it is a measure of the soil volume used almost exclusively by rooted or unrooted cuttings in the first and, possibly, the second year. This soil area must be well aerated (WD) with granular structure and friable (crushable) consistency. Soil color, which is an indicator of organic matter content, should be dark brown or dark gray brown (344% organic matter). A sandy loam or loam texture is ideal. Depth of the subsoil (B horizons) provides additional space for root development in older trees if it is not associated with layers that would impede root growth or restrict it altogether. In Chapter 3 there was a negative correlation (r=-O.79) between bulk density (ED) of subsoils at no and 60 cm, and poplar height growth. In loamy sands and sandy loams, BD was not restricting attéli7 gm/cms. However, is sandy clay loams, silt loans, silty clay loams, clay loans or clay, BD {1.4 gm/cm3 severely restricted roots, eliminating expansion in most cases. Soil texture, structure and organic matter content have a direct effect on soil moisture-holding capacity. In Chapter 2, Ap's consisting of sandy loans and loans, with fine granular structure and with dark 85 brown and dark gray brown colors (indicating 3-4% organic matter) had excellent surface soil moisture conditions. In the subsoil, presence of bands or layers at various depths with increases in clay and about 5% fine gravel contributed to additional soil moisture in the tree rooting zone of sandy loam or coarser loamy sand soil. Coarse-textured soil factors in Table 12 are grouped into three ranges of expected productivity as shown by five-year height growth in the PCA study. Optimum growth of 6.5 to 9.6 m in five years was measured on WD sandy loans with clay bands at 50 and 120 cm. A reduction to Moderate growth of 3.5 to 6.2 m in five years was due to a combination of reduced internal soil drainage, subsoil textures of silt loam, silty clay loam and clay loam with bulk densities 10.6 gm/cm3 and/or to plow' pans just under the Ap. Low potential (not recommended) with five-year growth of only 0.4 to 0.7 m, was the result of extremes in soil water conditions. Coarse, ED soils with a seasonal water table :3.8 m from the surface, or PD/VPD soils that were saturated to the soil surface or to the Ap most of the year are not suitable for intensive culture of hybrid poplar. SITE HISTORY AND POTENTIAL MANAGEMENT CONCERNS affect initial site selection and reflect soil/site factors most manageable by the grower (Table 13). Past land use of agricultural fields can have a.major influence on productivity of hybrid poplars. All of the PCA sites exhibiting exceptional five-year poplar growth were of optimum physical soil condition and had previously been in relatively high value agri- cultural crops for one to five years, or in orchard production for many years. Reduction to moderate growth occurred on hay fields (with legumes) on finer-textures soils, mainly due to soil compaction from harvesting on o.m 3 o.,c. so o5 8. o.n so monnm HHmsn no mzmcp and no ooHuozcona .eoe won a: s a. .a .8 won eeeaonnnsm m: a. .o. .a 5 :3 o. no} a 5 :3 once ion Son... :9. 2:. no 9...... rd Sn 3 ed 2 Saw Emu _a .2 . on: when c» on oceansm eonn :0 com -OOH actress chNHnoc ncoHnHecoo mcHonucn rpr oH no means :H :0 Rmi no to MN 0 no HHn :H omnonocH as m .nnm so as. can: as en 5n: 3 do .n .3 Thu we can.» re em on em rs echo mam rs £825 as .3 seem :5: den or rear Ao ncOHnnvon done Ho H no He no eHoHn no HHc .H on once: nonsmoH raH: as; no cannon .onznncd eononm Hone no .HHm .Hom encrono .noHnnw HHnso .onsnond cocoons: eHo co nonsmoH :LH: no: .nochnomo> .ncoop hna Home nnsoh miHv mm: nzanoa=H noes: nnHmom eHnahc mo HrHacogcm aaH>Huo=dona avenue page mzmaozoo szzwoonnnoo on cooH coo snoo zuH: Honncoo coo: new con: ocHanao .coHuooaaoo HHom ono>oo on mesoH mcomooo no: mcHnsc mcHumo>ncr HHon oaoH eon moHucoHd anoo now nHHon coon» co mcHOHhmonn .mcomoon N non onsaHso noHQOA ean»: on HoucoeHnnoe on one He no HHo .H no 580* nouns: 0Hnomnonso hoHouo .EQOH noHouHo .EoOH hoHo ALHHmuHon .EdOH nHHouHHm .eooH ono nozomuHow .eoOHuH .sooH accownHo .n:0HaoH>onDpo onsaxo» HHom cocoon oeHoHpno: no open noan: .mooco>Hnoommo ocHoHpnor wcHaoommo I o no Ho one so Rmn :OHHH: .HHoaaoo .mwonm knocooeoom .oweon do: an storm no ano no: annopdmon .ocoonH .omszo .cnou coxoonm he chose no onHo ans mange—090 §mNM marge—080 oxmm NN o>oao no osmm o>ono no osom m:0HuHU:oo sham sens o woewmnmwewmwnsn monomer oHu.ren= enhance new a oHoHocoHp .mHoHcoonoa nmzm on nooseon nH coco Ron noose mo OHaon cwschnc no omeoo no: m are none OHMHooAn oz Honesceod economosos Honacoo coo: mhoeeonesn scone mfl>oo onB EZMmHmm omono no>oo coonm no onsoos no mcoHpHeeo Hoscc< .dono o50H>onA non cocoon no muconnasc ionoHa one zumaz no chHnHeco Hoscc< 87 wet soils. Corn in northern Lower Michigan is usually grown on heavy soils (silty clay loam, clay loam) with reduced drainage (SWPD) because corn is more adapted to such conditions than other crops. Timing the harvest with ideal weather conditions in Michigan is often a "game of chance" and there is much trafficing on wet corn fields. Several of the PCA sites with very low productivity (not recommended for planting) were old pastures where hay was taken off year after year with no re- seeding or fertilizer additions. Most were eventually abandoned. Old, heavily-grazed pastures had similiar low productivity. On SWPD and PD sites where artifical drainage was not economical, pasture or yearly harvests of hay with no reseeding is a typical use for the area. Fields cropped with potatoes or strawberries are predominently coarse sands or loamy sands, required irrigation and may have prestcide residues (particularly fungicides) in the Ap that would be detrimental to hybrid poplars. The inherent fertility of a soil, the result of long-term soil development, is based on internal soil drainage, texture and organic matter; Past cropping may be equally important, however. Optimum PCA sites had all been in higher-value crops, and all had a deep, fertile Ap (up to 30 cm) with 4-5% organic matter, fine granular structure and ideal surface infiltration. Most of these fields had annual additions of animal manure and/or rotations with green manure crops. All sites with moderate growth were somewhat deficient in P or P and K: the Ap was not as deep, and it had less organic matter and a blockier structure. Poorly drained and VPD sites may have potentially high soil fertility due to a fibrous Ap with 75% to 28% organic matter, yet the saturated conditions do not allow sufficient oxygen for root uptake of both water and nutrients. 88 Analysis of N was not done in the PCA studies nor is it recom- mended because this nutrient is highly variable in form and quantity from season to season, and, therefore, difficult to assess. Fertiliz- ation with N is not recommended in the year of establishment because roots from cuttings, particularly if they are planted unrooted, are not well developed until late in the first growing season and much of the added N would be lost through leaching or denitrification. Weed problems are also compounded by first-year additions of N. There is no question that poplars would respond to N applications from the second year on, but economic limitations may prevent such fertilization. P, K and Mg are better contained in the soil system and can be applied in the first year. The field test suggested in Table 13 also included pH because it has a strong effect on nutrient availability. Weed competition on a potential planting site can seriously affect the growth and survival of hybrid poplar plantations in the initial years. vegetative competition robs newly-planted cuttings and young trees of moisture, nutrients and light (Chapters 2 and 3, Dickmann and Stuart 1983, Danfield et a1 1983, Raitanen.et.al’l983); it must be controlled and prevented from reestablishing during the first few years of growth. The best condition is bare soil; anything less than this level of control will reduce growth of poplars. On sites where erosion is a problem, however, some weed cover will have to te tolerated. Weeds may be controlled using conventinal farm tillage or a chemical no-till approach (Chapters 1 and 2, Dickmann & Koelling 1982). For small- scale plantings rototilling or hand cultivation is suitable. When using herbicides, the grower must know the growth habit of the weeds to be controlled. Perennials and biennials (particularly quackgrass) need 89 a post-emergent herbicide that is translocated to the roots of the plant. Annuals may be handled effectively by using pro-emergent herbicides at the beginning of the growing season. The relation of herbicide efficacy to soil texture and organic matter content also must be understood. Soil-applied herbicides with a long half-life (90 days) can be leached by moisture into the root zone on coarse- textured soils low in organic matter, thus damaging trees. On SWPD and PD fine-textured soils, herbicides at rates safe for hybrid poplars may be adsorbed on clay particles or organic matter and rendered inactive. On some sites, indicator plants may be used to identify potential problems. Excessively dry sites usually have a certain percentage of sand or gravelly sand without vegetation, plus some conbination of lichens, bracken fern, sumac or raspberry (NCRTC-lZl 1981). As clay content increases and soil textures grade to the heavier sandy clay loams, clay loans or clays and drainage falls to SWPD, wild carrot may dominate the site l/. Hop sedge also appears as drainage is reduced to SWOD. Reedcanary grass, cattail and willow are usually dominant on PD and VOD sites (NCRTC-lzl 1981). FIELD EVALUATION GUIDE FOR HYBRID POPLAR CULTURE Figure 8 summarizes soil/site identification factors in a step-by- step guide that maybe used in on-site evaluation of agricultural fields being considered for hybrid poplar plantings. For optimum potential, NATURAL SOIL DRAINAGE (NSD), EFFECTIVE GROWING SPACE (EGS) and SITE HISTORY AND PAST MANAGEMENT CONCERNS (SHPMC) should closely match those factors listed under OPTIMUM. When working with marginal land (which l/Tesar, Milo B., Professor, Department of Crop and Soil Science, Michigan State University, Personal communication. Figure 8. Field guide for evaluating the potential of agri- cultural fields for intensive culture of hybrid poplars. WD=well-drained, SWED=somewhat excessively drained, MWD-moderately well-drained, SWPD (moderate)=somewhat poorly drained that may be altered, SWPD (low)=somewhat poorly drained that is not recommended for hybrid poplars, PD=poorly drained, VPD=very poorly drained. s=sand, ls=loamy sand, sl=sandy loam, l=loam, scl=sandy clay loam, sil=silt loam, sic1=silty clay loam, cl=clay loam, c=c1ay. OM=organic matter, Aksurface horizon or plow layer, Solum=B horizons (can include C's) under Ap, Banding= narrow bands or horizons within the soil profile with increases of clay, organic matter and/or _5% fine gravel. 3] Surface drainage or agriculturally-designed ditches may be required. -2-/ Use complete tillage; no-till is not suitable. 2/ Use deep plowing or subsoiling if pan extends to considerable depth . E/ Use subsoiling to l m if necessary. OPTIMUM POTENTIA L ‘. 9O MODERATE POTENTIAL " Temummsmramn WD Cleer brown. m been. red. orange or red color. to _150 on :10 been. mt or orange settles within 150 on an the soil surfea Inter-able 150-200 on tree the soil surface nanomw, natural—Apnea “.mnnucmh) Moonstonmwor onngeeottleeet50ca. wetertahleetmcny SWPD(1ow): Mottlee at 15-20 on. ramble 90 on {re- soil euraoe L 0 W. NO POTEN TIA L 27!): 3e- ee PD with wearable at or abve the eeil “deco 315cm 7'03 mas '. V TOMMMSPACI Ap :ark gray or dark my brown with fine granular structure am :1 or 1 textm Sela-of la, elorltertul'e with 2' - or structure Preeeaoe of bending in e]. soil profile Consistent in theee eoil texturee to £200 on Apleeetmaucndeepm ”Loner-wanting] rfimveled/orooouee Morphwpamuy Solu- Irith eicl. oi or o torture uni/or blooh or moire mtm y el teatime out Mating n. Continuu- ortetein .‘ Origin). Av loot to eroeion on upper 3 at the eoil eta-face A]: of e, 3, cl or erode (suck) torture eat/or single grain or naive stricture Writ " - rcmmxmmemmmcom Pornroropeotdrybeene, vegetablee,enllsraim, orchardorheywithlen-e onelorltexture :iiofS.5-?.OiaAp ClofMinAp Maximum-Mm orgreenooverorope Sufficient Ca, P, Inning uehownbyeoilteet Fouruopofhaywithlem-e oooel,ei.lorsioltexture Fads-0.5.51!” (Hafiz-jinn rattled-nominal. leoretexturee 3o crop rotation for)“ 5 701-1" Detieunoyofmnutrient '. old deeded posture. (need peeture or potato field AW fan with waive soil oomtion history fl “(5.0 can->7.) iaAp <80! in aimnl soil or)” <3 inorganic eoil 301' mm mm 91 may be the rule rather than the exception) soil/site factors listed under MODERATE or LOW potential are frequently encountered. If, for example, NSD falls under MODERATE and all other conditions are OPTIMUM, then maximum suggested growth of about 1.3 m/year may be realized. If EGS and/or SHPMC also falls under MODERATE, growth potential may be severely reduced. Soil/site factors which may be altered are noted but the economics of such site alteration should be considered carefully. Any field with soil/site factors listed under Low should be rejected as unsuitable. When using Figure 8 to evaluate fields for potential hybrid poplar plantations, NSD and EGS may be identified by using a 150 cm (5 ft) bucket auger to sample the soil profile every 30 m apart across the field. The 150 cm depth is important because favorable soil moisture, nutrient and tree rooting factors between 100 and 150 cm from the surface may raise the potential productivity of an otherwise moderate site to optimum. Topography of a field greatly affects soil variability. On a 12-18% slope, for example, there may be several different soil con- ditions. On the other hand, sharp changes in vegetation type on a relatively flat field usually indicate changes in soil texture and pos- sibly drainage. In either case, transects with soil borings should be arranged on these areas as though they were separate "fields". For nutrient testing, one composite sample for each soil type is sufficient. To prepare, take 20, 125 cc (l/Z cup) samples per 4 ha (10 acres) from the Ap, mix well and prepare one 250 cm (1 cup) composite sample for mailing and send it to the Michigan State University (MSU) Soil Test Lab for tests of pH, Ca, P, K and Mg. Percent organic matter may be added to the analysis for an additional nominal charge. 92 On MWD and some SWPD sites, surface drainage may bring productivity up to optimum. On SWPD sites with high water tables, agriculturally- designed ditches may be necessary (Luthin 1957). However, such soil/ site alteration may be too costly, depending on original land investment and size of the potential plantation. One of the main factors which reduces potential productivity from optimum to moderate is high clay content, which may lead to surface and/or subsurface soil compaction. Surface soil compaction may be improved by fall plowing (not on wet soil!) then leaving the furrows to freeze and thaw during winter months. Sub- surface compaction may be improved by plowing or subsoiling to l m if necessary. CONCLUSIONS For successful plantation establishment, the soil/site conditions must match the expectations of the potential grower. While the extremely rapid growth that poplars are capable of is always welcome and usually desired, moderate growth may be sufficient for revegetation of bare sites, soil erosion control and wildlife plantings. With purchase or private production of top-quality planting material, control of competing vege- tation, and a thorough knowledge of the soil/site factors on a potential site, growers should be able to anticipate and realize their objectives. 93 REFERENCES Baker, James B. and W.M. Broadfoot. 1978. A new technique of site selection for hardwoods. So. J. of ADP. For. Vol. 2, p. 42-h3. Baker, James B. and W.H. Broadfoot. 1977. Site evaluation for eight important southern hardwoods. USDA For. Serv. Gen. Tech. Rep. 80-1“, 31 P . Barkley, B.A., H.W. Evers and W.E. Raitanen. 1983c. Soils: the forest foundation. In: New Forests in Eastern Ontario; Hybrid Poplar. Science and Technology Series, Vol. I. p. 63-82. Brissette, J.C., J.W. Hanover, T.J. Stadt and J.W. Hart. 1979. Improved poplars for Michigan through the Michigan State Coop- erative Tree Improvement Program. In: Proc. North Am. Poplar Council, 1979. Annual Meeting, Thompsville, MI. p. 115-122. Carmean, Willard H. 1975. Forest site quality evaluation in the United States. Adv. Agron. 27:209-269. Danfield, William, James Martishus and Edward Hansen. 1983. Application date affects herbicide tolerance of hybrid poplar. USDA For. Serv. Res. Note NC-BOl. # p. Demeritt, Maurice E. Jr. 1981a. 50 years of hytrid.poplar research in the northeast. In: 27th Proceedings of the Northeastern Forest Tree Improvement Conference, 1981. p. 166-183. Demeritt, Maurice E. Jr. 1981b. Growth of hybrid poplars in Pennsylvania and Maryland clonal tests. USDA For. Serv. Res. Note. NE-302, 2 p. Dickmann, Donald I. and Katherine W. Stuart. 1983. The Culture of Poplars in Eastern North America. Michigan State University, East Lansing, MI 48824. 168 p. Dickmann, Donald I. and Melvin R. Koelling. 1982. 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Setting out the crop. In: New Forests In Eastern Ontario: Hybrid Poplar. Science & Technology Series. vol. I. p. 133-186. Roberts, B.A. and M.A.K. Khalil. 1980. Detailed soil site assessment of hytrid poplar planting areas in Newfoundland. Environ. Canada, Forestry Service, Res. Note 36:1-21. Schreiner, E.J. 1959. Production of poplar timber in Europe and its significance and application in the U.S. USFS Ag. Handbook, No. 150. 124 p. U.S.D.A. Forest Service. 1973. The outlook for timber in the United States. States. USDA For. Res. Rep. No. 20. 367 p. Wendel, G.W. 1972. Results of a 20-year test of hytrid.poplars in West Virginia. USDA For. Serv. Res. Pap. NE-237. 7 D. Wood, H.B. 1977. Hydrologic differences between selected forested and agricultural soils in Hawaii. Soil Sci. Soc. Amer. J. 41:132-136. Zsuffa, L. 1983. Ontario's hybrid poplar programp-an historical perspective. In: New Forests in Eastern Ontario: Hybrid Poplar. Science & Technology Series, Vol. 1. p. 187-204. 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