SGs‘fiE EFFECB CF A COMMERCEALJYPE CLEARW’? CM SOEL AND WATER RELAHGNS ON A 554%.?!“ WOODED WATERSHED 'Fheaé: €57 rho Segre: of @h. D. RMCHEGAN STATE UREVERSETY Sam—9% Emmi-6? ioh’f‘zmp 1953 This is to certify that the thesis entitled Some Effects of A Commercial-Type Clearcut on Soil and Water Relations on a Small Wooded Watershed presented by George Bernard Coltharp has been accepted towards fulfillment of the requirements for Ph. D. degree ma f" 7/2? % Major professor in Forestry S tember 2 1958 Date ep ’ 0-169 LIBRARY Michigan State University . * QC, _') «r I I 1 fl 55/?“ AUG 0 2 2003 SOME EFFETS OF A GOMI‘IERCIAIPTYPE CLEARCUT 0N SOIL AND WATER RELATIONS ON.A SHALL WOODBD'HATERSHED By GEORGE BERNARD co LTHARP Submitted to the School for Advanced Graduate Studies of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements fer the degree or DOCTOR OF PHILOSOPHY Deparument of Forestry 1958 ACKNOWLEDGMENTS The author extends sincere appreciation to Dr. D. P. White, who, as major professor, supervised the study. Appreciation is extended to Dr. T. D. Stevens, Head, Department of Forestry, for advice and assistance given throughout the course or the study. Grateful acknowledgment is also due to Dr. W. D. Baton, Experiment Station statistician, fer his help with the statis- tical analyses employed in the study, and to Dr. A. E. Erickson, Soil Science Department, for his valuable help with the soil analyses. The author is indebted to Drs. In M. James and F. D. Freeland, Forestry Department, and others for their helpful suggestions and assistance. Appreciation is also extended to the'Michigan Hydro- logic Research Station, a coOperative project or the Agricultural Research Service of the U. S. Department of Agriculture and the Michigan.Agricultura1 Experiment Station, for the aid and facilities furnished the author. 11 VITA George Bernard.Coltharp candidate for the degree of Doctor of Philosophy Final examination, 2:00 P.H., September 2, 1958 Dissertation: Some Effects of a.Commercia1otype Clearcut on Soil and Water Relations on a Small wooded Watershed Outline of Studies Major subject: Forestry Minor subjects: Hydrology, Soil Science Biographical Items Born, Nbvember 28, 1928, Maringouin, Louisiana Undergraduate Studies, MoNeese Jr. College, 19h6 - 19h? Iouisiana State University, 19h? - 1951 Graduate Studies, Colorado State University, l95h - 1955, Michigan State University, 1955 - 1958 Experience: Member United States Army, 1951 - 1953, Forestry Aide, Research, U. 8. Forest Service, 1956 - 1957. Graduate Research Assistant, Michigan State University, 1955 - 1958 Member: Xi Sigma Pi, Society of mmerican.Foresters, American Forestry Association, American.Geophysical Union 111 SOME EFFETS OF A COWERCIAL-TYPE CIEARCUT ON SOIL AND WATER RELATIONS ON A SMALL HOODED WATERSHED By GEORGE BERNARD comma!» AN ABSMG '1' Suhaitted to the School for Advanced Graduate Studies of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOG'IOR OF PHI IOSOPHY Department of Forestry Year 1958 Approved 0¢ua,LA f) 4/1““ cli/ ABSTRACT Because of the increased interest manifest in the water resources of southern lower~Michigan it is highly desirable to ascertain the water yield contributions of areas under various types of land use and vegetative cover. The purpose of this study was to determine and evaluate the effects of a commercial-type clearcut on soil and water rela- tions on a small wooded watershed representative of the farm woodlot-type. , . A small wooded watershed, located within the Rose Lake wildlife Experiment Station approximately ten miles northeast of East lensing, Michigan, was established during 19141. The watershed, supporting a well stocked stand of the oak-hickory type, was calibrated hydrologically for an eleven year period. During the fall and winter of 1951 the forest cover on the watershed was subjected to a commercial-type clearcut opera- tion, removing all trees larger than 5.5 inches d.b.h. Hydrologic data were obtained after treatment through 1957. Detailed soil sampling fer soil physical property determinations was accomplished on the watershed during 1953, 1957. and on the adjacent uncut area during 1957. Gravimetric soilxmoisture sampling was initiated during the latter part of 19h5 and continued on.a bi-weekly basis through 1952. Weekly soil moisture samples were obtained from March through September of 1957. v These soil and hydrologic data were obtained in an effort to determine and evaluate the effects of the vegeta- tive treatment on the soil reservoir and the water yield of the watershed. The results of the study do not indicate any pronounced chance in soil texture, bulk density, porosity, and permea- bili ty as a result of treatment. There was an apparent increase in soil organic matter and a decrease in unincorpo- rated organic matter. Soil moisture showed a very definite and statistically significant increase during the growing season of 1952 as a result of treatment. During 195? soil moisture values were intermediate between the high values of 1952 and the mean pre-treatment values. Computed evapotranspiration values were lower during the 1952 growing season than during the pro-treatment period or during 1957. Mean soil and air temperatures were generally increased as a result of treatment. Average monthly and annual runoff, maximum rates of runoff, and average volume per runoff decreased slightly dur- ing the post-treatment period. The average infiltration rate for the watershed, as determined by hydrograph analysis, increased slightly after treatment. A hydrologic summary for the entire period of study indicated no significant change in the established hydrologic characteristics of the watershed. vi The commercial-type clearcut has apparently not had any deleterious effects on the soils of the watershed nor on the water resources of the area. vii TABLE OF CONTENTS Page ACKNOWIBDGMERTS....................ii VITA. . . . . . . . . . . . . . . . . . . . . . . . . . iii ABSTRACT........................ iv HSTOFTABLES..................... xi LISTOFFIGURES.................... xiv Chapter I.INTRODUCTION.................. l II.REVIEwoFm'rERATURE.............. 3 111. DESCRIPTION OF THE PROJEGT.AND STUDY AREA . . . 2h The wooded watershed. . . . . . . . . . . . . 26 Iocation.................. 26 Geology and physiography. . . . . . . . . . Climate.................. Soils................... Vegetation. . . . . . . . . . . . . . . . . IV. HISTORY OF THE HOODED WATERSHED STUDY . . . . . Instrumentation............... Precipitation............... Temperature................ RumrrO O O O O O C O O O O O O O O O O O O fififittfiursrs EI‘OOIOfleeeeeeeeeeeeeeeeee SOillflOiflmrQeeeeeeeeeeeeeee “6 Chapter Page Calibration.period, 19h1 - 1951 . . . . . . . h8 Treaunent,1951...............149 Post-treatment period, 1952 - 1957. . . . . . 52 V. METHODS OF STUDY. . . . . . . . . . . . . . . . 55 Determination of treatment effects on physical properties . . . . . . . . Soil physical properties. Soil texture. Permeability. Porosity. . . Bulk density. Field capacity. Permanent wilting percentage. Loss on ignition. . . . . . Soil.moisture reghme. . . . . Evapotranspiration. . . . . . Soil temperature regime . . . Unincorporated organic matter Determination of treatment effects on yieldandqualityeeeeeeeee Rumffeeeeeee Infiltration. . Emaiqneeeeee VI. RESULES AND DISCUSSION. ix soil . . . . 56 . . . . S7 . . . . 61 . . . . 61 . . . . 61 . . . . 63 . . . . 63 . . . . 63 . . . . 6h . . . . 65 . . . . 68 . . . . 68 . . . . 69 water . . . . 69 . . . . 70 . . . . 7O . . . . 71 . . . . 72 Chapter Page Soil studies. . . . . . . . . . . . . . . . . 72 Soil physical properties. . . . . . . . . . 72 Soil texture. . . . . . . . . . . . . . . 73 Bulk density. . . . . . . . . . . . . . . 77 Porosity. . . . . . . . . . . . . . . . . 80 Permeability. . . . . . . . . . . . . . . 87 Field capacity. . . . . . . . . . . . . . 92 Penmanent wilting percentage. . . . . . . 93 Loss on ignition. . . . . . . . . . . . . 95 Unincorporated organic matter . . . . . . . 98 Soil moisture regime. . . . . . . . . . . . 101 Evapotranspiration. . . . . . . . . . . . . 11? Soil temperature regime . . . . . . . . . . 121 Hydrologic studies. . . . . . . . . . . . . . 132 Runoff. . . . . . . . . . . . . . . . . . . 132 Infiltration................llll Erosion . . . . . . . . . . . . . . . . . . lh3 Hydrologic smmuary. . . . . . . . . . . . . m5 VII. SUMMARYANDCONCIUSIONS.. .... . ..... . 150 The study. . . . . . . . . . . . . . . . . . . 150 Findings of the study. . . . . . . . . . . . . 151 Soils. . . . . . . . . . . . . . . . . . . . 151 Hydrology. . . . . . . . . . . . . . . . . . 15h LITERATURE CITED. . . . . . . . . . . . . . . . . . . . 156 x Table 1. 2. 3. 5. 6. 7. 8. 9. 10. 11. 12a. 12c . 13a. .LIST OF TABLES Basal Area by Species. . . . . . . . . . . . . Basal Area by One Inch Diameter Classes. . . . Susanary of Results of Mechanical Analysis, 1957 . . . . . . . . . . . . . . . . . . . . Summary of Results of Mechanical Analysis, 1953.................... Summary of Bulk Density Values . . . . . . . . Summary of Total, Capillary, and Mon-capillary pore space . . . . . . . . . . . . . . . . . Smary of Porosity Values at Various Tensions Smary of Percolation Rates in Inches per Hour Summary of Soil Moisture Equilibrium Points. . Relative Soil Organdc Matter*Content . . . . . Total Unincorporated Organic Matter. . . . . . Average Monthly Soil Moisture, During the Growing Season, Metamora Sandy ham, 0 - 36 Inch Depth, 19h6 - 1952 and 1957 . . . . . . Analysis of Variance . . . . . . . . . . . . . Studentised Range Test . . . . . . . . . . . . Average Monthly Soil Moisture During the Period of'Maximum.Transpirational Draft, 0 - 36 Inch Depth, Metamora Sandy Loam, l9h6 - 1952 and 1957eeeeeeeeeeeeeeeeeeee x1 Page 3? he 75 76 79 83 85 91 9h 97 100 110 110 111 112 Table 13b. 13c. lua. 1hb. 15e 16. 17. 18.e 18b. 19. 20. 21. 22. Analysis of Variance . . . . . . . . . . . . . . Studentized Range Test . . . . . . . . . . . . . Average Monthly Precipitation During the Growing Season, 19h6 - 1952 and 1957 . . . . . Analysis of Variance . . . . . . . . . . . . . . Average Monthly Soil.Moisture During the Growing Season, 0 - 36 Inch.Depth, by 3011 Type, 1957. . . . . . . . . . . . . . . . Correlation Between 8011 Moisture Contents of Watershed Soils. . . . . . . . . . . . . . . . Average Daily and Monthly Evapotranspiration During June - September, 19ue - 1952 and 1957. Analysis of Variance of Average Daily Evapotranspiration Values. . . . . . . . . . . Studentized Range Analysis . . . . . . . . . . . Mean Monthly Soil and Air Temperatures, l9h6 - 1956. . . . . . . . . . . . . . . . . . Frequency of Air Temperature at h.5 Feet and Six Inches Equaling or Exceeding Prescribed Temperatures . . . . . . . . . . . . . . . . . Monthly and Annual Precipitation and Runoff, l9h1 - 1957. . . . . . . . . . . . . . . . . . Frequency of Runoff, 19141 - 1957 . . . . . . . . xii Page 112 113 11h 11h 116 117 119 120 120 123 125 13h 139 Table . Page 23. Precipitation and Runoff fer Individual Storms, 19hl - 1957. . . . . . . . . . . . . . 1h0 214. Maximum Rate of Runoff per Year, 19111 - 1957 . m2 25. Average Infiltration Rate per Storm During The Growing 8688011, 19“.]. " 19S7e e e e e e e e e e ll"... 26. Hydrologic Summary, 19h1 - 1957. . . . . . . . . 1R6 xiii LIST OF FIGURES Figure 1. 2. 3. h. 5. 6. 7. 8. 9. 10. 11. 12. 13. 15. Location of the flooded watershed, with Reference to the Lansing Area and to the State. Map of the wooded.Watershed Showing Soil Types and Hydrologic and Meteorologic Installations Slope Class Distribution on the Hooded watershed. Monthly Distribution of Precipitation . . . . . Vegetation of the Needed Watershed, May, 1951 . CrownTCover Maps of the wooded Watershed. . . . Meteorological Station at the Wooded Watershed. Runoff Measuring Installations at the wooded watershed . . . . . . . . . . . . . . . .k. . Stand.Condition on the Watershed Immediately After Logging . . . . . . . . . . . . . . . . Vegetative Cover, Summer of 1952. . . . . . . . Vegetative28 23.___:-m_e..oc {as :2... i x“. 58. are. seeszfoa no.3 .cEeEEoo . . n Eco. .632 In? accent . .. .. Eco. .2650va raccoon :om I a I 90 .. Eco. aces» c.oE2e2 Ion ozwowm m...om 8...... Reese; .1. A seat .8565... -1. . =2. tap at . £2.81}: . ozmem: as). u hfigfi define id 1:... ' v gatorsneeseaiag.» asnafii§QLEESQ . .1 comment a... emcee... .2813: Rain scene none 95. Saw mhzwiamhmz. 0.00405; A ‘ v‘f' '1 v 30 The weighted average slope is 6.1 per cent, with the maximum slope not exceeding fourteen per cent (Fig. 3). The maximum relief is sixteen feet. The elevation of the outlet of the watershed is 833oh1 feet above sea level. Two intermittent streams drain the watershed, dividing it roughly into thirds (Fig. 2). Each of the intermittent streams have a length of approximately 3&0 feet from source to outlet of the watershed with average channel slopes of 3.5 per cent and 2.9 per cent respectively for the westerndmost channel and easternemost channel. The channels of these intermittent streams are not well defined. Climate The climate of the area alternates between continental and semimarine with changing meteorological conditions (Wills, l9h1). The marine type is due to the influence of the Great Lakes, which, in turn, is governed by the force and direction of the wind. When there is little or no wind, the weather becomes continental in character, which.means pronounced fluctuations in temperature - hot weather in the summer and severe cold in the winter. Likewise, a strong wind from the Lakes may immediately transform.the weather into a semimarine type. Precipitation is well distributed throughout the year, with no conspicuous variations noted in the seasonsl.merch. The average annual precipitation for the East Lansing area 31 “Cofipmnw Sommmmm, awmdQOsz .wonmnopmz omwooz one no aoapsnaapmap mmmHo macaw: « C e m ow 0 pk m 0 H Home l [L ’ .pm -hu EBEQDIMD Joua>m ski VTN. nhf ”To. vvd O. -0 nh.nn 0.0 and» 0 av on.a v -n 0‘: eh n -N (meduo ma<40 hzuocwa uaOJm ozuomd 32 is 31.08 inches.1 Figure h illustrates the seasonal distri- bution of precipitation. The wettest month of the year is May with an average of 3.75 inches, while the driest month is February with 1.81 inches. The precipitation averages 17.96 inches during the growing season of April through September. Precipitation received during the months of’October through March is primarily in the form of snow with a total annual fall of h9.2 inches (Eaton and Eichmeier, 1951). The area has a mean annual temperature of h6.9°F, with a mean winter temperature of 2h.2°F and a mean summer tempera- ture of 68.6“F. Temperature extremes that have been recorded are 102°F and -26°F.2 The average date of the last spring frost is May S and of the first fall frost is October 10. The growing season averages 158 days. Evaporation values, as determined from.a standard U. S.‘Weather Bureau Class A Evaporation Pan, are relatively low. Average evaporation for the months of May through October is 6.31 inches. Solar radiation, which seems to be highly corre- lated with evaporation, is well below the mean values for the 1Precipitation values are based on thirty year normals furnished the Michigan Hydrologic Research Project by Mr. A. H. Eichmeier, U. S. Weather Bureau, East lensing, Michigan. 2Temperature data from Climate and Man, l9hl, U. S. Department of Agriculture, Agricultural Yearbbok. All other hydrologic and meteorologic data, unless otherwise cited, are from the files of the Michigan Hydrologic Research Project. 33 2.35 unease: .m .p 53.508 .m 4 .sz 3 8395 noamooem o." odofiohm sewage“: on» command.“ mango: uoausudoaooan no cememv 5039:9393 no soap—Sauna? hnnpnozlé .NE may not 0 m 4 h. h 2 4 ho \s & . \\\\\\\\ a \ \\\\\\\ = b\\\\\\\ \ = seam handgun—ocean soqouI - uonsa ydtoeaa 3h United States (Crabb, 1950). The average annual amount of solar radiation for the East Lansing area is 102,602 Langleys (gram-calories per square centimeter). Wind movement, which is important in this area because of its ameliorating influence on weather, is greatest during the period from November to April and least from May to October. The prevailing wind direction is from the southwest. agile The soils of the wooded watershed belong to the Gray- Brown Podzolic Great Soil Group. These soils are derived from medium to heavy textured calcareous drift of the late Wisconsin glacial period (Leverett and Schneider, 1917). The drift covering is sufficiently thick (at least eighty feet) in this area to completely mask any direct influence of the underlying bedrock on the soils. The drift consists of trans- ported residue of weathered material and rock fragments of shales, limestones, and sandstones with some crystalline rock material from distant sources included. The Rose Lake area falls within the Fox-Plainfield— Hillsdale-Bellefontaine Soil Association as mapped by Veatch (1953). Johnsgard, at 51., (19142) mapped the area immediately around and including the watershed as Hillsdale sandy loam, rolling phase. More specifically, the soils within the watershed were mapped in 191w as Miami loam, Hillsdale sandy loam, Hillsdale 35 sandy loam - Metea sandy loam complex, Conover loam, Conover silt loam.3 Intensive soil sampling during 1957 by the writer indicated that the soil formerly mapped as Conover silt loam was sandy loam in texture and has been reclassified as Meta- mora sandy loam (Fig. 2). The soils may be subdivided into two groups on the basis of drainage: 1) Well-drained soils, and 2) imperfectly drained soils. The well-drained group includes the Miami loam, Hillsdale sandy loam, and Hillsdale sandy loam - Metea sandy loam complex. The imperfectly drained group includes the Conover loan and the Metamora sandy loam. The physical properties of these soils are discussed in detail in Chapter VI. Vegetation The forest vegetation of this area is representative of the northern portion of the central hardwood region. Prior to cutting (winter of 1951 - 1952) the watershed sup- ported a well—stocked stand of second growth oak-hickory (Fig. 5). The timber had been "high graded" at various times since settlement of the area in the mid-1800's. 3The soils of the watershed were mapped by Mr. Leo R. Jones, Soil Conservation Service, U. S. Department of Agriculture. ‘fiuu-uwmw——~ awe w 0‘ (a) view is noff station. Note the (b) view is towards the May, 1951. ion of the ru density of reproduction in the center of the photo. S.-Vegetation on the wooded watershed, west across the center of the watershed. Fig. towards the south from the approach sect watershed during the summer of 1951 (Smith, l95h). 37 .An intensive vegetative inventory was made on the The inven- tory included a cruise of all stems one inch in diameter and larger. A crown map was also made showing the projection of all crowns of stems one inch in diameter and larger (Fig. 6a). Table 1 gives the basal area for the watershed by species. TABLE 1 BASAL AREA BY spasms" Species Basal area per acre A Querous velutina Quercus rubra Quercus alba Carya ovata Carya ovalis Prunus serotina Acer rubra Prunus virginiana Ulmus thomasi Crataegus spp. Cornus racemosa Hammelis virginiana Fraxinus americana' 32.818 20.515 16.821 17 . 369 10.607 n.359 1.259 .812 .227 . 167 .026 .017 .013 ‘From Smith, 1951;. 38 Rm; .330 was no HES sound .waa no noESdm one madman oUmE Any .puesumoap Boondofio cahpnamaoaoEEoo one .uSaneHo thBIHwHvoEEoo 0p momma .Hmma no aeSESm on» mqfimsm once Adv .Uosmoeumz popooz on» 90 moms am>oo czosol.w .mam 39 This tabulation indicates the oaks (Quercus velutina Iam., Quercus‘ggbgg L., Quercus‘glbg L.) contained 66.8 per cent of the basal area, and the hickories (92313 ovalis Sarg., 92222.2!232HM111‘) contained 26.6 per cent, for a combined total of 93-h per cent of the stand, hence the designation of the forest type as oak-hickory was well justified. Basal area by one inch diameter classes is given in Table 2. There was a total of 8,912 board feet (International one-fourth inch log rule) on the watershed in the 10- to 18- inch diameter class (Smith and Crabb, 1953). This amounted to 5,570 board feet per acre. The largest volume of saw timber was in black oak (guercus velutina Iam.). In the 5- to 9- inch.class there were hSh cubic feet per acre. Of a total of 2,008 stems on the watershed in the 1- to l9—inch category, 83.9 per cent were less than five inches in diameter. A lesser vegetation survey made on nine fifteen feet square quadrats indicated that h6.2 per cent of the area had no lesser vegetation.(Smith,‘gp.‘gig.). Dense concentrations of lesser vegetation were noted in the few openings in the stand (Fig. 5). The status of the watershed vegetation after cutting is given in Chapter IV. TABLE 2 ho BASAL AREA BY ONE INCH DIAMETER GLASSESa Diameter class Basal area (inches) (square feet) Per cent of total 1 3.8h5 2.2 2 3.8u9 2.2 3 2.158 1.2 h . 1.7h9 1.0 5 5.397 3.1 6 6.7h9 3.9 7 7.096 h.1 8 15.958 9.2 9 9.670 5.7 10 16.053 9.3 11 18.898 10.9 12 17.128 9.9 13 16.335 9.5 11 22.368 12.9 15 10.660 6.1 16 5.395 3.1 17 h-675 2.7 13 3.517 2.0 19 1.887 1.0 ‘From Smith, 19511. CHAPTER IV HISTORY OF THE HOODED WATERSHED STUDY The Michigan Hydrologic Research Project was formally established January 1, 19110. The project was originally set up to study watershed conditions under the influence of agri- cultural cropping practices prevailing in this area. However, it was decided during the sumer of 19110 to include a water- shed under forested conditions to contrast the effects of various kinds of cover conditions on the hydrology of small agricultural watersheds. An agreement was formulated between the Michigan Department of Conservation, the Michigan Agri- cultural Experiment Station, and the Soil Conservation Service of the U. S. Department of Agriculture to utilize lands of the Rose Lake Wildlife Experiment Station for the purpose of studying watershed conditions under a forest cover. The small wooded watershed north of Clinton County Road 1:511 was selected as the site for the watershed study. Surveying, mapping, construction of installations, and instrumentation of the study area were effected during the latter half of 1911.0 and January of 19111. Instrumentation Precipitation In order to study the hydrology of an area it is neces- sary to know how much precipitation is received on the area. Precipitation received on the watershed during the months of April through October occurs primarily as rainfall. During the months of November through March precipitation occurs primarily as snow. Precipitation records have been taken since February, l9hl at the watershed. The total amount of precipitation was measured with a standard U. S. Weather Bureau type, eight inch non-recording rain gage. A nine inch weighing-type (Ferguson) recording rain gage was used to determine precipitation intensity. As a supplemental measurement, a standard non-recording rain gage equipped with a Nipher shield was used to determine the reliability of rain and snow measurements under conditions of high wind. Precipitation was measured as soon as possible after each storm, to prevent undue losses from.the gages by evapo- ration. Also, as the recording rain gage used a twelve hour chart with a clock that ran for one week it was necessary to change the chart as soon as possible after precipitation in order to prevent confusion as to the timing of the precipita- tion. For winter snow measurements the catchment funnels were removed from all three gages to allow easy access of the #3 snow. An anti-freeze solution was added to the precipitation catchment pail of the recording gage to reduce the snow catch to its liquid content. The water content of the snow caught in the standard gages (shielded and non-shielded) was obtained by melting the snow catch per gage on a small kerosene stove. In addition to the snow measurements obtained in the precipi- tation gages a snow survey was made on the watershed after each.snowfall. As the depth of snow on the ground seldom exceeds ten inches in this area it was impractical to use a snow tube in the conventional manner, viz., obtaining a repre— sentative core of snow in the tube, then weighing the tube and snow core on a specially calibrated scale to get water content. Consequently, a special method was used, employing a snow tube of the conventional type. It has been determined that the cross-sectional area of the snow tube is approximately 1/28 the cross-sectional area of a standard eight inch rain gage. Hence by getting twenty-eight snow cores at random from.the watershed area a representative sample of snow depth and water content was obtained which.was equivalent in cross- sectional area to a catch obtained in a standard gage. The snow was melted and measured as in the case of the catch in the standard gages. All precipitation data were recorded as inches depth of water and inches per hour. In the case of snow, average depth of snowfall and average snow density were also recorded. m. The data were tabulated by days, months, and years. A sum- mary of precipitation received on the area for the period of study, 191.1 - 1957 is included in Chapter VI. Temperature Air temperature and relative humidity were recorded by means of a hygrothermograph located in a standard Weather Bureau instrument shelter 11.5 feet above ground (Fig. 7). The air temperature and relative humidity fluctuations were recorded on a weekly, clock operated chart. Maximum and minimum air temperatures were determined by means of a U- Type maximum - minimum thermometer. Air temperatures were tabulated as maximum and minimum values per week as well as average weekly temperature. Soil temperatures were obtained at depths of one inch and six inches below the soil surface by means of a recording three-pen thermograph. The third pen of the thermograph recorded air temperature six inches above the soil surface. The soil and air temperatures were tabulated as weekly maxi- mum and minimum, and average weekly temperature per location. Runoff Runoff was measured by means of a float-type portable water stage recorder used in conjunction with a metal 3-H type flume. A reinforced concrete approach section at the outlet of the watershed delivers the water to the flume in an orderly manner. The runoff recorder was equipped with an 1&5 2.3.335 noaeeeem camonoanhm cswduedxv .eMsm can." meanness.» enhpnwnflwaos donate 89% new." magaocoaunoa ncmdnm pudendum .ewew can." pace-mean nepaegmuaonnoaz .uaopoaoeaofi Efiaaséflfiuwse was madam soEonuoamhn wanna—on Academe passages.“ 353”." 0» “CS“ Eon.» .oae eueonno one essences: cocoa: on» no «.333.» Handmadgoeuezcé .mfim M6 adjustable float stop so that the float never dropped below the zero point of bouyancy. The float stop was equipped with a vernier and could be read to the nearest 0.001 foot. Figure 8 pictures the runoff measuring installations. Runoff data were recorded as cubic feet per second (e.f.s.), and area inches per hour. Runoff data fer the period of study, l9hl - 1957, are summarized in Chapter VI. Erosion As runoff water passed through the measuring flume it flowed into a reinforced concrete silt box. This silt box would hold runoff water to a depth of two feet, with the remainder flowing over a weir plate at the lower end. A Ramser divisor, located on the side of the silt box at the level of the weir plate, obtained an aliquot sample of all runoff flowing over the weir plate (Fig. 8). Total soil loss was obtained by determining soil loss per cubic foot caught in the divisor, multiplying by the total volume of runoff passing over the weir plate and adding that to the total soil loss obtained in the silt box. Soil loss was computed in terms of pounds per acre. Soil Moisture Soil moisture sampling was initiated on the watershed during September of l9u5. Bi-weekly gravimetric sampling, with a Veihmeyer tube, in the Metamora sandy 10mm furnished a measure of soil moisture for the watershed. Bouyoucos 1+7 Anoapspm noaooeem eawoaohphm «39335 .aepaooca owepu nope: mcacfleanoo canon seaflonn Am. :39 page 2: .eeSHH ooh» mum Am. 3393.3. honefim Amy $093.3 seesaw new and» nonsense :v .ponmaopes 006003 05 pa goflmanauead wanna—uses uuoqsmué .wrm w fem-39‘“ "1“ ‘5 h8 :moisture blocks were installed in the same soil type during the summer of 1953 and weekly readings of soil moisture at various depths were recorded. The blocks were removed during the summer of 1957 and new blocks were installed. Weekly gravimetric sampling was initiated during March of 1957 and continued through September of 1957. During this period of gravimetric sampling all five soil types on the watershed were sampled. A more detailed description of the soil moisture samp- ling procedure is given in Chapter V. Calibration Period, 19111 - 1951 In watershed studies, such as this, it is desirable to accumulate data on the various meteorologic and hydrologic factors under a diversity of conditions as might normally be encountered on a particular area. This standardization or calibration.period varies according to climatic and physio- graphic factors. Statistical methods have been developed which enable the calculation of the desired calibration period for a particular set of conditions (Kovener and Evans, l9Sh). However, no such calculations were available at the beginning of this study, thus an arbitrary length of calibration period was decided on. The instrumentation of the watershed was completed by February 1, l9hl and meteorological and hydrological records 11-9 were comenced from that date. Pro-treatment data were acctmalated through November of 1951. Theatment, 1951 By the summer of 1951 the watershed had undergone an eleven year period of standardization and it was felt that in that period a representative cross-section of storms had been experienced on the area. Consequently the Hydrologio Project Committee recomended that the forest canopy be altered in order to ebserve changes, if any, in runoff, erosion, and silting. As a result of this reconlnendation the ”Joint Working Plan of the Michigan Agricultural Experiment Station and the Soil Conservation Service," which formed the working basis for the Michigan Hydrologic Research Project, was amended November 26, 1951 to include the following treat- ment: 1 1. The present forest cover at the wooded watershed to be altered so as to give additional data on the effects of watershed management on soil and water losses. This alteration to be accomplished by com- mercially clearcutting in the same manner as is com- mon in southern Michigan woedle ts. In addition, an isolation strip 50 feet wide around the watershed will be treated similarly to eliminate edge effect. 2. Commercial clearcutting will take all trees down to the 5- inch diameter class. Trees 10 inches and 1'li‘rom the files of the Michigan Hydrologic Research Station. 50 larger in diameter will be cut into sawlogs. Material in the 6-inch to 9-inch diameter classes will be out into cordwood. Cruise data indicates a volume of 8,000 board feet in the watershed. Cutting an isola- tion strip will increase this volume to approximately 12,000 board feet. All material will be cut and decked outside the cutting area, and will become the property of the Rose Lake Wildlife Experiment Station. The expense of cutting and decking operations will be borne by the Forestry Department. Tops will be left in the area unless the Rose Lake Wildlife Experiment Station desires to utilize them for fuelwood or brush- pilee for game cover. 3. Clearcutting operations will comence about November 27, 1951, and continue until the project is completed. 11. This cultural treatment will not change the use of the area by the Game Division, Michigan Conservation 3 Department. 5. This cultural treatment will not change the present instrumentation of the watershed, nor the studies now underway thereon. This treatment was carried out, as proposed, by the end of the year 1951. The trees were felled, bucked, and tractor skidded to a landing off the watershed area. There was no attempt to minimize soil disturbance on the area. Approximately 1600 stems, less than five inches in diameter, remained on the watershed, with many of these damaged by the logging operation (Fig. 9). As the entire treatment operation required only a min- imum amount of time, approximately one month, only a few data were collected during this transitory period. Likewise, as this period of the year is more or less dormant, from a hydro- logic standpoint, the entire 1951 year was included in the pro-treatment period. Fig. 9.-Stand condition on the watershed immediately after logging. (a) View from the northwest towards the southeast. (b) View from south to north. (Michigan Hydrologic Research Station) 51 52 Post Treatment Period, 1952 - 1957 After the initial cutting treatment, during the fall and winter of 1951, no further treatment was effected on the area. The first year after treatment, 1952, was the only year the watershed was affected by the full impact of the treatment. With each subsequent year the regrowth of vegeta- tion became more dense, hence the effect of the treatment was progressively ameliorated. Figure 10 illustrates the regrowth of vegetation during the 1952 season, while Figure 11 indicates vegetative cover during 1957. The vegetative cover was very dense during the 1957 drawing season, with nearly 100 per cent crown coverage for the watershed. The vegetation type varied from grass cover on one small area to bramble to sapling stage of cherry, elm, oak, and hickory, with a few pole-sized trees of the same species. -There were profuse growths of black- berry and wild grape on scattered areas. 53 3033a noaoooom camOHoaohm :omEouzv .oononopoz on» we houses on» ooohoo one: Op pose Eon.“ 39; .Nmmfi Mo hog- ..Ho>oc oouuooowo>o.on .wg h. 5 331.com nonooeom camoacaohm monument .655 Tm one 3 woes-ea cease: 23.325 monocoom oewodonehm nowanzv noeonaae ouoaoaoe on» o.“ onsamonou .hmon yo page 30.: used: uqooewno on» :H .hmoa Ho nansm .oonoaoooz on» no no>oo ooapeoowoafitma .mg on» no noooo o>3ouomo>lenn .wam CHAPTER V METHODS OF STUDY Research related to the hydrologic effects of vegetation treatment has generally followed.one or more of the following :methods or techniques: Measurement of water yield and sediment from small watersheds on which the vegetation or land use has been altered or on groups of watersheds which are similar except for vegetative cover or land use; measurement of sample plots upon which vegetation can be manipulated; area sampling of hydrologic conditions on land areas which have undergone vegetation changes. Each.method has considerable merit, as well as disadvantages: The first approach has the disadvantage that only the end results of treatment are measured, i.e. run- off. The second approach.deals only with the various compone onto which affect water yield from an area, but do not in themselves measure the end result. The third approach per- mite a relative measure of the effects of vegetation and land use treatments but does not attain any degree of specific delineation of cause or effect of treatment. Ideally, a com- bination.of the first and second approaches would furnish the maximum amount of useful information, as the individual comp ponents affecting water yield on the watershed would be meas- ured, as well as the end result of the interaction of these components, i.e. runoff. 56 In.order to determine and evaluate some of the effects of a commercial-type clearcut on soil and water relations on a small watershed it was considered desirable to use a method of study approaching a combination of the first and second methods mentioned above. Consequently the methods of study have been separated into parts: The determination of some effects of treatment on soil physical properties; and the determination of some effects of treatment on water yield and quality. Determination of Treatment Effects on 8011 Physical Properties Soil may be regarded as a product of its environment and as such it is not a static body but is dynamic and may be expected to change with modification of its environment. Since vegetation is a component of the environsent of an area any drastic changes in the vegetative cover'may promote changes in the physical constitution of the sclum. This por- tion of the dissertation is concerned with the determination of effects of vegetation treatment on soil physical properties. The basic procedure employed in this study was to determine the physical characteristics of the soils on the watershed during the last year of study, 1957, and contrast these values with soils of the some type on untreated areas immediately adjacent to the treated watershed area. Also these values were to be contrasted with values obtained in 57 1953, one year after treatment, by Smith (19Sh)on the water- shed area. The basic approach should have included determi- nation of soil physical properties prior to vegetative treat- ment and subsequent determinations of these properties at pre- scribed intervals. This, however, was not the case, hence the procedure described above was employed. Soil thsical Properties The physical properties determined in this study were soil texture, permeability, porosity, bulk density, moisture equilibrium points (field capacity and permanent wilting point), and loss on ignition. The above physical pr0perties were determined from soil.samples extracted from the various soil types represented on.the watershed and the immediately surrounding area. Figure 13 indicates the location of the soil sampling pits on the watershed. The basic soil samples consisted of soil cores, three inohes in diameter by three inches high, extracted in aluminum cylinders by means of a core sampler similar to that originally described by But: (19h0), (Fig. 1h). The sampling procedure generally followed that described by Hoover, pp'gl,, (195h). Only one soil sampling pit was excavated within each soil type on the water- shed because of the limited area occupied by each soil type and to prevent, as much as possible, any overall disturbance to the watershed. The depths sampled were 0 - 6 inches, 12 - 18 inches, 30 - 36 inches, and h2 - h8 inches. The sampling 58 Soil 21293 _ I 36 Metamora sandy loam he Conover loam 0 Soil Moisture 115 Miami 1 Sampling Station cm 8 3011 Physical 610 Hillsdale sandy loam 11:39:”: Sampling 610 - 619 Hillsdale sandy loam- Metea sandy loam Fig. lB.-Location of soil moisture sampling stations and soil physical property sampling pits. 59 oawoacaohm newdnoazv Afloapmpm seasoned .haoumhonmd on» on mohoo Adan wqaphonnnmnu hon naoaama lace oncogenes unaa oao no on: on» 0002 .0»: :a goddamn choc Haomu.:d .mam n 6O depths, down through thirty-six inches, were selected to coincide with the soil moisture sampling depths originally selected in 19145. The greatest depth, 142 - 11.8 inches, was selected to coincide with the additional depth of soil moist- ure sampling in 1957. The writer felt that physical changes in the soil, associated with vegetation or land use changes, are not usually effected below a depth of six inches (except with cultivation), hence physical prOperty determinations on the soils of the untreated area were confined to the upper six inches of the profile. Three cores were obtained from each.sampling depth in order to reduce, somewhat, the natural variability of the soils and also to have at least one or two cores for each depth in the event that a core had to be discarded because of large root channels or rocks. The soil cores were placed in one-pint cylindrical cardboard containers to prevent dry- ing and to protect the relatively undisturbed structure dur- ing transit to the laboratory. The soils were sampled when the moisture was at field capacity or slightly below. Past investigations indicate that at this moisture content struct- ural cracks and cleavages are closed and there is sufficient moisture in the soil to lubricate the sample, hence a rela- tively undisturbed sample may be obtained. Bulk samples were obtained, in addition to the soil cores, for use in determining loss on ignition, permanent 61 wilting percentage, and soil texture. Soil texture. The texture of the soil indicates the relative proportion of sand, silt, and clay separates which constitute the soil body. A.mechanical analysis, using the Bouyoucos hydrometer method, was employed in the laboratory to determine the soil textures (Forest Soils Committee of the Douglas Fir Region. 1953). The relative proportions of sand, silt, and clay were expressed as percentages of total separ- ates less than 2 mm. in size. Permeability.-.Permeability, as expressed by percola- tion rates (inches per hour), was determined in the labora- tory on the 3 X 3 —inch.soil cores with a permeability appa- ratus described by Hoover, _e_t, _a_l_., o . 9_i_t. Figure 15 illustrates the permeability apparatus. Porosity. A tension table, similar to that originally described by leaner and Shaw (l9hl), was used fer pore space determinations. The previously described 3 X 3 oinch.soil cores were subjected to tensions of 20 mm., ho cm., and 60 cm, Total porosity, capillary porosity, and non-capillary porosity values were determined following procedures outlined by Hoover, g; 3;” 9g._,9_;_,t. The delineation between capillary and non-capillary porosity was attained by considering the 60 cm. tension value as representing the force with which capillary water is held. Thus, the porosity values obtained at 60 cm. of tension represented capillary porosity. Porosity values were expressed as per cent of soil volume. Fig. 15.-Permeability apparatus used for determ- ining percolation rates of soil cores. 62 63 Bulk density. The bulk density of each core sample was obtained after the permeability and porosity values were determined. The ovenpdry weight of the soil core in grams was divided by the volume of the core in cubic centhmeters to obtain the bulk density values. After completing the bulk density determinations all soil cores were examined for large stones and roots which would tend to exaggerate the pemeability, porosity, and bulk density values. Any such cores found were discarded. Field capacity. Various methods have been advanced for the determination of soil moisture content at the moist- ure equilibrium point known as field capacity. The reason for the variety of“methods apparently rests on the lack of agreement as to the tension value most representative of the attraction.of the soil particles for water at the so called field capacity condition. If the moisture held in the pore space at 60 am. of tension represents capillary moisture, and that is the assumptionumade in this study as indicated in the above section on.porosity, then the moisture content at this tension level should indicate approthate field capacity. Permanent‘fliltigg Percentag . The use of fifteen atmospheres of tension as representative of the attraction of soil for water at the permanent wilting percentage has gained rather widespread acceptance among researchers (Baver, 1956), 6!; hence this tension value was used in this study. The pres- sure-membrane apparatus, as described by Richards (19h? ), was used to determine the moisture content at permanent wilting point. A plastic sausage casing-type membrane was used in the apparatus. Rubber rings were used to retain the soil samples within the apparatus. The soils were sieved through a 2 m. screen before being tested. Moisture contents at the permanent wilting point were expressed as per cent moisture on an oven-dry basis and on a volume basis. Loss on ignition. The values obtained from loss on ignition represent an approximation of total soil organic matter (Forest Soils Committee of the Douglas Fir Region, 1953). For sandy soils loss on ignition values are probably the most accurate indication of soil organic matter content. In clay soils, however, water intimately associated with the soil particles may be driven off, giving inaccurate values for organic matter content. Therefore, all values represent- ing total soil organic matter, as determined in this disser- tation, are presented as loss on ignition. Ten gram samples of oven-dry soil, ground to pass through a 60 mesh screen, were ignited in a muffle furnace at 600’0 for four hours. The results obtained were expressed as per cent loss on igni- tion. 65 Soil Moistgye Raging Soil moisture values were determined gravimetrically for depths of O - 6 inches, 12 - 18 inches, and 30 - 36 inches. The soil moisture sampling area was located within the Meta- mora sandy loam soil type (see Fig. 2, Chap. 111). The samp- ling depths, as well 'as the soil type to be sampled, were decided by personnel of the Michigan Hydrologic Research Station in 1915. The soil moisture values were obtained on a bi-weekly basis from September, 19145 through December, 1952. In order to ascertain the degree of soil moisture variation beWeen soil types on the watershed, weekly soil moisture samples were obtained from the five soil types during the period of March through September, 1957. The depths sampled were the same as the three previously mentioned plus an addi- tional depth of 1+2 - 348 inches. Fifteen soil moisture samp- ling stations were established on the watershed early in 1957, with three sample stations within each soil type. However, with subsequent revision of soil type boundaries, some soil types contained only two sample stations while others con- tained four (Fig. 13). The soil moisture samples were obtained with a Veihmeyer tube (Veihmeyer, 1929). and placed in air-tight alumimim sample cans (Fig. 16). The moisture samples were weighed to the nearest one-tenth of a gram. The samples were oven-dried at a temperature of 105'6 for a twenty-four hour period (Dull and Reinhart, 1955). Soil 66 Fig. 16.-Gravimetric soil moisture sampling by means of a Veihmeyer tube. Note wooden trough used to hold the soil cores. (Michigan Hydrologic Research Station) 67 moisture values were determined as per cent moisture on an oven-dried weight basis. The values were also expressed as per cent moisture on a volume basis by multiplying per cent moisture on an oven-dried weight basis by the bulk density value for the appropriate soil and depth. In order to account for the intervening depths between the depths actually sampled, for determining total profile moisture content (0 - 1;.8 inches), arbitrary depths, based on the writer's observations of the profiles, were assigned as follows: Depth Sampled Representative Depth (inches) (inches) 0 - 6 0 - 6 12 - 18 7 - 25 3O - 36 26 - 36 142 - 1&8 37 - 1&8 There were no usable soil moisture values obtained during the years 1953 - 1956. Plaster-of-paris soil moisture blocks, developed by Bouyoucos and Mick (1913.0), were installed in the listeners sandy loam soil during the stunner of 1953. 'l‘tse blocks failed to give satisfactory results, perhaps because of the wet site, and were never calibrated, thus the results obtained were of no use to this study. These soil moisture blocks were removed during the sumer of 1957 and the more recently developed nylon-type moisture blocks (Bouyoucos, 1952) were installed in the same area. As 68 gravimetric samples were obtained during the 1957 growing season no data were used from the moisture blocks in this a “dye lvapg transpi ration Bvapotranspiration values were computed for periods when soil moisture was at or below field capacity, in order to reduce as much as possible incorporation of percolation losses in the computed values. Hhen soil moisture depletion occurred, evapotranspiration equaled the difference between any two consecutive soil moisture values plus precipitation received during the period. When soil moisture accretion occurred, the amount of evapotranspiration equaled the pre- cipitation minus the amount of soil moisture increase. Evapotranspiration values were computed from mean monthly soil moisture values and monthly precipitation, and expressed as mean daily and monthly values for the period of June through September. .3011 Temperature Regime Soil temperatures were determined at depths of one j~11ch and six inches below the surface by means of a three- A third temperature element was Figure 2 indicates Den soil thermograph. located six inches above the soil surface. the location of the three-pen thermograph, which was on the Hillsdale sandy loam - Metea sandy loam complex. The temperature records used in this study include the years 69 l9h6 through 1951 (pro-treatment period) and 1952 through 1957 (post-treatment period). Average weekly and monthly temperatures from each of the three locations or depths were compared with average weekly and monthly air temperatures at h.5 feet above ground (hygrothermograph at meteorological station) to detemine effects of treatment on soil and sur— face air temperatures. Unincogporated Organic Matter A measure of the amount of unincorporated organic matter, i.e. all organic matter down to mineral soil, on the treated watershed area and the surrounding untreated area was obtained during November of .1957. All unincorporated organic matter, excluding limbs and large twigs, was collected from within one foot square sample plots. Samples were obtained from within each soil type on the watershed and corresponding soil types on the untreated area immediately adjacent to the watershed. The samples were oven-dried at lOO'C for twenty-four hours and the oven-dry weight recorded. The weight of unincorporated organic matter on each soil type was expressed as tons per acre. Determination of Treannent Effects on Water Yield and Quality Runoff or water yield from the watershed represents the net results of the interaction of the various vegetative and pedologic factors affecting the disposition of precipi- 7O tation on the watershed. By studying the runoff behavior of the watershed before and after vegetative treatment the over- all hydrologic effect of treatment may be ascertained. The quality of water (silt content) running off from the water- shed serves as an indication of the effectiveness of the vegetative cover in protecting the soil from raindrop impact and the securing action of surface runoff. Therefore, a com— parison of erosion amounts before and after treatment may indicate whether the treatment reduced the effectiveness of the vegetative cover. 52119.11 Runoff records were available for the entire period 0 1' study, 19ul . - 1957. Runoff characteristics, i.e. average annual runoff, average monthly runoff, average runoff per 8 term, average maximmn rates of runoff per hour and twenty— 1"’Dur hours, average rate per storm, and frequency of runoff were determined for the pro-treatment period and contrasted '1 th post-treatment runoff characteristics. All runoff data Were analyzed in consideration of precipitation received on the area. 1. Infiltration The average infiltration rate, in inches per hour, ( few) for the watershed (includes interception losses) was determined for storms occuring during the frost-free season. Hydrograph analysis, as described by Foster (191(8), was 7l employed to determine the average infiltration rate. Infil- tration rates for stems occuring before treatment were con- trasted with rates for storms after treatment, in an attempt to detect effects of vegetative treatment. Erosion ‘ The silt content of all runoff water was determined 1'or the, entire period of study, 19141 - 1957. Pre-treatment amounts, expressed as pounds per acre, were contrasted to post-treatment amounts in order to ascertain any degree of change which might be attributable to treatment effect. CHAPTER VI RESULTS AND DI SCUSSION The results of this study of some effects of a commer- cial-type clearcut on soil and water relations on a small wooded watershed are presented in two parts. The first part is devoted to the presentation and discussion of the results of the soil studies. The second part is devoted to the results of the hydrologic aspects of the study. Soil Studies The soil is the fundamental water regulating agent on a watershed. The physical characteristics of the soil deter- mines its hydrologic characteristics, i.e. infiltration, per- colation, and storage capacity. These characteristics in turn determine the disposition of precipitation in terms of surface runoff, subsurface flow, and water storage within the soil‘mantle. Soil Physical Properties Because physical properties of soils are rather sensi- tive to vegetation and land use changes it is of fundamental importance in watershed management research to ascertain the effects of these changes or treatments on the soil physical preperties in order to evaluate any changes in water regime of an area. The study of runoff and erosion from a treated 73 watershed indicates the nature of the treatment on water regime, but in order to determine the reasons why the treat- ment causes certain.changes in.water regime it is necessary to first determine what changes are effected in the soil reservoir. Soil texture. Soil texture refers to the relative preportions of sand, silt, and clay separates in the soil. As the number and size distribution of soil particles in a unit volume determines soil texture, texture determines the amount of surface area, and in turn, the water holding capac- ity of the soil. For a given volume of soil, the smaller the size of primary particles the greater the water holding capacity. The kmerican Society of'Civil Engineers (l9h9) indicates that clay can hold nine times as much water as fine sand against the force of gravity. The retention storage capacity, in terms of inches depth of water per foot depth of soil, of sandy loam is given as 1.7 inches, loam.3.3 inches, and clay h.5 inches. From.the above discussion it is appar- ent that soil texture has a definite hydrologic function. Since it is generally recognized that the texture of the soil can be altered very little by vegetative treatment (Lute and Chandler, 19159), the purpose for the determination of soil texture in this study was to furnish a check on the previously established textural classifications as well as provide textural information for additional depths of soils 7h not previously sampled. Soil texture data, as determined by means of mechan- ical analyses, are given for the various soil types and depths in Table 3. Textural data obtained by Smith (1951:.) are given in Table 11 as a comparison. The results of the mechanical analyses in both tables are rather comparable, with one nota- ble exception. Smith's data list a soil type as Conover silt loam, while in the present study this soil type is listed as Metamora sandy loam. This constitutes a considerable dis- crepancy as to textural designation and the only plausible explanation offered is that the classification as silt loam is a result of the vagarities of sampling. The writer sampled the soil type in question intensively during the smer of 1957 and failed to detect any occurrence of a silt loam tex- ture. The soil type would have fomally been classified as Conover sandy loam but is now being mapped as Hetamora sandy loam.1 The soils of the watershed exhibited a certain degree of similarity of texture in that all soils at all depths were classified as being loamy in nature, varying from sandy loam to clay loam. Loam soils are generally recognized as exhibit- ing favorable hydrologic properties as well as being more 1The affirmation of this soil type was made in consul- tation with Mr. Ivan Schneider of the Soil Science Department at Michigan State University. TIBLE 3 75 SUMMARY OF RESULTS OF HEWGAL ANALYSIS, 1957 Soil type and depth Distribution.of se arates < 2 m. saga silt clay Texture Metamora sandy loam 0'- 6 inch.depth 12 - 18 inch depth 30 - 36 inch depth u2 - h8 inch depth Conover loam 0 - 6 inch depth 12 - 18 inch.depth 30 - 36 inch depth h2 - u8 inch depth Miami loam 0 — 6 inch depth 12 - 18 inch depth 30 - 36 inch depth h2 - h8 inch.depth Hillsdale sandy loam- Metea sandy loam O - 6 inch depth 12 - 18 inch depth 30 - 36 inch depth hZ - h8 inch depth Hillsdale sandy loam 0 - 6 inch depth 12 - 18 inch.depth 30 - 36 inch depth h2 - h8 inch depth -:Pir cent - 67.h 22.2 10.h 70.0 18.0 12.0 63.2 25.8 11.0 50.0 39.8 10.2 h1.2 39.6 19.2 37.2 32.6 30.2 9.2 56.3 3h.h 51.2 37. 11.0 7.2 h5.2 1 .6 g... 3... .3. 702 ne6 13.2 71.h 12.h 16.2 62.2 28.6 9.2 67.2 25.6 7.2 55.0 2h.2 20.8 75.0 13.h 11.6 60.0 28.2 11.2 58.8 2306 1706 51.8 23.6 2’4e6 68.8 18.6 12.6 sandy loam sandy loam sandy loam loam loan clay loam silty clay loam loam loam clay loam sandy loam sandy loam sandy loam sandy loam sandy clay loam sandy loam sandy loam sandy loam sandy clay loam sandy loam TIBLE h SUMMARY or RESULTS or MEEMHCAL mums, 1953 (mos 3mm, 1951+) Distribution of Soil type and depth se arates < 2 m. sand sIIt clay - Per cent - Conover silt loam 0 - 3 inch depth 30.3 59.7 10.0 h - 7 inch depth 31.3 51.3 17.14 12 - 15 113011 depth 32.0 52e3 15s? Conover loan 0 - 3 inch depth 65.2 16.8 18.0 1% " 7 inch dQPth 67a is} 1700 " 15 131011 depth 72s e3 12e9 Miami loam 0 - 3 inch depth 15.3 38.1 15.7 h ‘l 7 inch depth (+7e3 35.0 lges 12 - 15 inch depth 1.0.0 31.0 2 .0 Rillsdale sandy loam- Metea sandy loam complex 0 " 3 inch depth 63e9 28e5 708‘ h - 7 inch depth 61.0 29.2 9.9 12 - 15 inch depth 50.0 26.2 .8 Hillsdale sandy loan 0 - 3 inch depth - - - h - 7 inch depth . 60.6 30.1 10. 12 - 15 inch depth 57.1 26.1 16. 77 favorable for forest growth than either coarse sands or fine clays. The part of this chapter devoted to hydrologic studies indicates the generally favorable hydrologic characteristics of these soils. Bulk density". The bulk density of a soil may be de- fined as the ratio between the dry weight of a given volume of undisturbed soil. and the weight of an equal volume of water (Luts and Chandler, 1914.7). Volume weight and apparent density are terms frequently used in place of bulk density. One of the most important factors influencing bulk density is soil structure. Very compact soils, with low pore volume, have high bulk density values. In contrast, loose, porous soils have low bulk densities. Consequently, since the bulk density of soils is greatly affected by soil structure, the measurement of bulk density should give a relative indi- cation of the structural condition of a soil, providing, of course, that soil texture is also considered. Organic matter 13 another factor which influences soil bulk density. With other factors being equal, soils with a high content of organic matter have lower bulk densities than soils with a low organic IlI-ntter content. With other factors being the same, a soil with a low bulk density would have a greater percolation rate, better aeration, and greater detention storage than a soil “211311 high bulk density. It can be seen, therefore, that for Q given soil if the bulk density values increase after vege- 78 tative treatment a deleterious hydrologic effect would likely be the result. Bulk density values have been obtained by soil type for various depths on the watershed the second year after treatment, 1953. (Smith, l95h), the sixth.year after treat- ment, 1957, and on the adjacent untreated area during 1957. These bulk density values have been summarized and are pre- sented in Table 5. The results of the study indicate consid- erable variation between values obtained during 1953 and 1957 in the upper six inches of the profile. The 1953 values are consistently lower than the 1957 values in the upper six inches, while the values for the 12 - 18 inch depth are of similar magnitude for these two years. Because the location of’sample plots used in 1953 are unknown it is rather diffi- cult to directly compare data for the two sampling years. The apparently lower bulk density values obtained during 1953 may be attributed to a thorough mixing of mineral soil and unincorporated organic matter in areas disturbed by skidding. The data indicate very little compaction attribu- table to logging. The values for the upper six inches obtained on the watershed during 1957 were consistantly lower than the values obtained on the adjacent area during the same year. loss on ignition values, which are presented in a following section, indicate higher relative organic matter content in the upper six inches of the watershed soils than 79 mm 5 SUMMARY OF BUIK DENSITY VAIUES Treated Treated Untreated Soil type and depth watershed watershed area 1953‘ 1957 1957 Metamora sandy loam 0 - 3 inch depth 1.36 1.30 - 3 - 6 inch depth 1.68 1.56 «- 12 - 18 inch depth 1.60 1.59 " 30 - 36 inch depth - 1.62 - 142 - 148 inch depth - 1.63 «- Conover loan 0 " 3 inch depth 1.00 .88 loll 3 - 6 inch depth 1.27 1.20 1.147 12 - 18 inch depth 1.05 1.53 - 3O «- £6 inch depth - 1.141 - 142 - 8 inch depth - 1.148 - Miami loam 0 - 3 inch depth .70 1.10 1.18 3 - 6 inch dOPth 1e01 lea]. 1e30 12 - 18 inch depth 1.51 1.39 - 3(2) - 36 inch depth - 1.6g - - 148 inch depth - 1.6 «- Hillsdale sandy loam- Metea sandy loam complex 0 - 3 inch depth .87 .97 1.22 3 - 6 inch depth 1.09 1.29 1.142 12 - 18 inch depth 1.143 1. O - 3O - 36 inch depth - 1. 7 - 142 - 148 inch depth - 1.55 - Hillsdale sandy loam 0 - 3 inch depth .76 1.15 1.19 3 - 6 inch depth 1.01 1.33 1.63 12 - 18 inch depth 1.35 1.77 - 30 - 36 inch depth - 1.70 - 1.42 - 148 inch depth - 1.57 '- 3From Smith, 19511. TIBLE 5 SUMMARY OF BULK DENSITY VALUES Treated Treated Untreated Soil type and depth watershed watershed area 1953‘ 1957 1957 Metamora sandy loan 0 " 3 111Gb depth 1e36 1e30 " 3 - 6 inch depth 1e68 1e56 " - 18 inch depth 1.60 1.59 - -36 inch depth - 1.62 - 142- 148 inch depth - 1.63 - Comver loam 0 - 3 inch depth 1.00 .88 1.11 3 - 6 inch depth 1.27 1.20 1.147 - 18 inch depth .05 1.53 - 3O - 36 inch depth - 1.141 - 142- 148 inch depth - 1.148 - Miami loam 0 - 3 inCh dOPth e70 1.10 1.18 3 - 6 inGh dCPth 1e01 lea]. 1e30 12 - 18 inch depth 1e51 1e39 ' 3(2) - 36 inch depth - 1.6 - - 148 inch depth - 1.6 - Hillsdale sandy loam- Metea sandy loam complex 0 - 3 inch depth .87 .97 1.22 3 - 6 inch depth 1.09 1.29 1.142 12 - 18 inch depth 1.143 1. O - - 36 inch depth 1. 7 - 142-148 inch depth - 1.55 - Hillsdale sandy loam O " 3 inch depth e76 1e15 1019 3 - 6 inch depth 1.01 1.33 1.63 12 - 18 inch depth 1.35 1.77 - 30 - 36 inch depth - 1.70 - 142 - 148 inch depth - 1.57 - __ aFrom Smith, 19511. 80 in.the soils on the adjacent untreated area. This higher organic matter content may be a contributing factor to the lower bulk density values on the watershed. As indicated in Table 5 the watershed soils were rather compact below thirty inches and in.some instances below twelve inches. The bulk density averages 1.6 for the 30 - 1.48 inch depths, which is quite high for soils of medium texture. This degree of compactness exhibited by the soils probably offers sufficient resistance to prevent free access to tree roots. The writer observed very few roots below thirty inches depth.when obtaining soil samples. Veihmeyer and Hendrickson (19h8) have shown that roots do not readily penetrate sands with bulk densities greater than 1.75 and clays with bulk densities greater than 1.h6 to 1. 63. From a hydrologic standpoint, restriction.of the:maJority of tree roots to the upper thirty inches of soil would reduce the retention storage Opportunity of the soil. Porosity. Baver (1956) has defined soil porosity as the percentage of soil volume which is not occupied by solid particles. Soil porosity is one of the more important phys- ical preperties of soils, as considered from the standpoint of hydrology and watershed management. Hursh.and Hoover (19h1) state "Two most essential soil profile characteristics pertinent to hydrologic studies are functions of porosity. They are storage opportunity and the transmission rate of 81 water." Since the soil acts as the reservoir of the water- shed, soil porosity serves as an indicator of total storage space for water in the reservoir. The relative distribution of’pore sizes, i.e. capillary and non-capillary, is of more practical significance than total porosity. A soil with a high percentage of capillary pore space will have a high retention capacity and a low percolation rate. Such soils would also be less likely to be droughty. A soil, on the other hand, which contained a large proportion of non-capil- lary pore space would have a low retention capacity, rela- tively high percolation rate, and would tend to be droughty. Soil pore space constitutes two types of water storage space, retention.and detention.storage. Retention storage refers to the water held by the soil particles against the force of gravity, or capillary storage. This water moves so slowly as to be considered for all practical purposes as being in storage. Hater in retention storage is available for use by vegetation and evaporation, but is unavailable for stremmflow. Non-capillary or large pores provide another form of storage. ‘Water moves downward through these pores under the influence of gravity and is only temporarily detained, hence the use of the term detention storage. This water is available for streamflow or to replenish the ground water supply. 82 It is apparent that the storage space provided by soil pore volume is of utmost importance from.a hydrologic stand- point and any change in the type and amount of pore space by vegetative treatment would be of great importance. Lassen, ‘gglgl., (1951) state "The effects of land use and vegetation on the soil are reflected principally in the resulting changes in the number, shape, and size of its pores." A summary of total, capillary, and non-capillary por- osity values is given in Table 6. Porosity values at various tensions are also given in Thble 7. The results of the study indicate a rather favorable total pore volume in the upper six inches of soil for all soils examined. However, capillary porosity accounts for approximately seventy per cent of the total porosity while more ideally constituted soils would contain fifty per cent capillary porosity and fifty per cent non-capillary porosity. Below twelve inches depth the total pore volume drops considerably, i.e. less than forty per cent. At these lower depths capillary porosity accounts for an even higher percentage of the total pore volume. At a depth of 30 - 36 inches in the Hillsdale sandy loam the capillary porosity accounts for eighténine per cent of the total porosity. These low porosity values are reflected in the bulk density values in the preceding section and the percola- tion rates in the following section on permeability. 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I ’ 4 z 0 \‘ o .J \‘ E u. <5 \ w’. 5 ’ a l’ a_ I a ’1 I (9 ‘~ 2 ‘ - § I- ‘ .l m‘ .. s 3 o 00 O D O ID '0 N N -' " I1H9I3M ABX) 3).-H1190" “"05 35 O 106 III 3 no IIIIIII 3 z .— ' e) O uumm I'- IIII g a) Immmu o IIIIIIII : < mmmmmmmmmmmmmmmm :3 IIIII 3 a umemmmmu g II a a mmuuummmmmummm >- IIIIIIII < 2 eumeeummem a: IIIIIII k ( «mm» m IIIII“! 1 «mm» a II. n: a run mmmn 2 see: III ( ma-mmu 5 N 00 0 Q to N -- (SBHONI) NOIlVUdIGBUd Fig. 180 SOIL MOISTURE VARIATION 30' - 36' DEPTH METAMCRA SAIDY LOAN O '0 O n Ill-I98 ‘2 -~.--|-9-SE v --- m. vfl'- o—‘fl. -- \ i» is 2 ‘ _. u. o 4 0. o ‘2’ o .. l..| t- Ise a "- 3 n o C) O n N N — '- M ABX) BUnlSIOW 'IIOS O tGGI "INN!" ZSGI I I I ICGI ° GOGI 5 co 0 v '0 N - (SBHONI) NOIlViIdIOBHd FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC JAN 107 108 o _ III to | o | | ‘ > “ III...- 0 z .- ' o O llllllllll *- a. I III In “ m N I0 llllllllllll ‘9 g IIIIIIII : < Illmmifllllllllllllllllllmlllilllllll 5 IIIII 3 a mmmuummu g II a , IllllllIllmlllllllllllllllllllllllll >- IIIIIIII ‘t ' 2 g m a: ' :3 I- : unuaueummmm a: 9 ‘ IIIIIII 3 g o F‘ E J \ w m >' ‘ S? 5' I” a mum at y“ S 0 3 IIII <2: 0 I no 2 ' ' .4 > 3 g I (I. “ o ’ I u. o a mum: to 0 <1 III an on B “ m 2 1: o z 1.95: uuuum z - ace: III ‘ use: «see: a (SSHONI) BHniSIOW 318V WIVAV (SBHONI) NOIlViIdIOSUd 109 cance between mean monthly values of soil moisture during the growing season (actually March through September) for the individual years. Table 12a summarizes the average monthly soil moisture values in inches of available water for 0 - 36 inches depth, for the years 19h6 - 1952 and 1957. The analy- sis of variance indicated a highly significant (one per cent level) difference between monthly soil moisture means for the individual years, Table 12b. To determine which years were significantly different the mean soil moisture values for the individual years were subjected to a "studentized range" test (Duncan, 1955). The results of this analysis, Table 12c, indicate that 1952 soil moisture values were significantly different (five per cent level) from all other years except 19h? and 1957. The two years, 1... 19h? and 1957. both received more precipitation than the year 1952 (Table me), which perhaps explains the lack of significant difference. As a further attempt to ascertain the effect of vege- tative treatment on soil moisture content of the 0 - 36 inch depth the average monthly soil moisture for the period of maximum transpirational draft, i.e. July, August, and Septem- ber, for the individual years of the study were analyzed statistically. Table 13a summarizes the soil moisture data for this period. The analysis of variance indicated a highly significant difference (one per cent level) between the indi- vidual years, Table 13b. To determine which years were 110 TABIE 12 I AVERAGE MONTHLY SOIL MOISTURE, DURING THE GROWING SEASON, METAMORA SANDY 10AM, o - 36 INCH DEPTH, 19u6 - 1952 AND 1957 191i6 19h? 19MB" 19119 1950 1951 1952 1957 March 7.02 -6f71h8736 av. “373028181306 6.3!). 7.06 April 7.00 7.06 7.06 7.06 7.06 7.06 7.06 7.0a May 7.06 7.06 7.06 7.06 6.32 7.06 6.82 7.06 June 6.7a 7.06 6.33 6.0h 7.06 6.90 7.06 6.26 July 2.09 5.39 3.65 2.83 5.11 3.36 6.Ii9 6.81; August .88 2.66 1.29 .95 2.12 1.28 6.62 h.62 September 1.56 5.06 1.17 .63 2.95 1.81 7.06 Ii.l7 "1x72133122"'RIZE'EIETKEB‘IES"EDIE-'£:53"Z:§5"6:i§" b ANAIXSIS 0F VARIANCE W Sums of Source of Degrees of variation freedom squares Mean squares F YOOJ‘B 7 33075 “~68 3e60“ Months 6 185.93 30.99 Error 172 94.57 1.30 "Significant at the one per cent level. 111 TABLE 12 (continued) c STUDENTIZED RANGE TEST l9h6 19h? 19h8 19h9 1950 1951 1952 1957 19u6 - N83 NS NS NS NS 3b 8 19h? - NS 3 NS Ns NS NS 19h8 - as NS us 3 N3 19u9 - NS NS 3 s 1950 - NS 3 N3 1951 - 3 N3 1952 - NS 1957 - aNDt significant at the five per cent level. bSignificant at the five per cent level. significantly different the monthly soil moisture means for the individual years were subjected to the "studentized range" test. The results of this test, Table 13c, indicate 1952 soil moisture values were significantly different from all other years at the five per cent level and significantly different from all except 1957 at the one per cent level. On the basis of the statistical analyses it appears that the vegetative treatment significantly increased soil TABLE 13 112 AVERAGE MONTHLY SOIL MOISTURE DURING THE PERIOD OF MAXIMUM TRANSPIRATIONAL DRAFT, 0 - 36 INCH DEPTH, METAMORA SANDN IoAM, 19h6 - 1952 AND 1957 19116 191).? 1911.8 1914.9 1950 1951 1952 1957 - inches of avaIIaEIe water - July 2e09 5039 3.65 2083 5011 3036 60169 608,4- August .88 2.66 1.29 .95 2.142 1.28 6.62 17.62 Soptanber 1e56 5e06 lei? e63 2e95 1.81 7e06 “417 Average 1.51 h.37 2.0h 1th? 3oh9 2.15 6.72 5.21 b ANAIXSIS OF VARIANCE Source of De rees of Sums of variation fgeedom squares Mean squares F T0158]. 23 100e53 ‘Years 7 77.95 11.1% 21.u2** Menths 2 15.36 7.6 Error in A 7.22 .52 “Significant at the one per cent level. 113 c STUDENTIZED RANGE 19h6 19h? I9u8 l9h9 1950 1951 1952 I957 - TIveBper cent leveI - I9u6 88 NS NS 3 NS 3 3 19h? s s 3 NS 3 a N3 19u6 NS 3 NS 3 NS 3 s 19h9 N3 3 N3 N3 3 s 1950 3 NS N3 3 s s s 1951 N3 3 NS N3 Na 3 s 1952 s s s s s‘ s 1957 3 NS 3 5 NS 3 Ns - onepper cent level - aSignificant bHon-significant moisture during 1952. However, soil moisture during 1957 seemed to be approaching pre-treatment conditions. As mentioned previously, the amount of precipitation affects the amount of moisture in the soil. To determine whether average monthly precipitation fer the growing season for the individual years Of study was significantly different an analysis of variance was employed. Table lha presents monthly precipitation during the months of March through September for the years l9h6 through 1952 and 1957. The TABLE 1h 11h AVERAGE NONTELI PRECIPITATION DURING THE GRONING SEASON l9h6 - 1952 AND 1957 ‘__‘ 19h6 19h? 19h8 19h9 1950 1951 1952 1957 -1nches - March 2.19 1.8h h.O8 2.28 2.06 1.76 2.09 1.62 April .70 5.78 2.11 2.05 h.61 3.80 3.58 3.h6 May 3.96 h.23 h.28 2.16 2.22 3.09 h.09 5.66 Juno 3e66 3e31 3e98 Bell-3 ue9l‘. Bel? 1e15 3015 July .18 2.81 2.75 3.77 n.7s 1.11 2.79 7.22 August 1.16 5.33 1.33 2.06 3.h0 2-5h h.35 1.87 September 1.71 5.66 2.1h 2.62 3.91 2.72 1.68 1.60 Average 1e9u “am 2095 2e62 3e70 2061‘. 2e82 3.51 .- b ANALKSIS OF VARIANCE Source of Degrees of Sums of variation freedom. squares Mean squares F Total 55 112.111 Years 7 2h.29 3.h7 1.91 Months 6 11.39 1.90 Error h2 76.h6 1.82 115 average monthly precipitation was not significantly different for the individual years of study (Table lub). 0f the two primary factors affecting available soil moisture i.e. precipi- tation and vegetation, precipitation did not prove signifi- cantly different for the period of study. It therefore appears that significant soil moisture increases can be attrib- uted to vegetative treatment. The increases in soil.moisture noted in this study cannot be attributed entirely to evapo- transpiration reduction, but also to reduced interception losses. Soil.moisture sampling, prior to 1957, was restricted to the Metamora sandy loam.soil type. To establish the rela- tionship between soil.moisture on the sampled soil to that of the other types on the watershed a correlation analysis was run on the data in Table 15. This table summarises average monthly available soil moisture in the 0 - 36 inch depth for the five soil types on the watershed. Table 16 presents the results of the correlation analysis. It appears that soil moisture in the Metamora sandy loam varies as the soil moist- ure varies in the other watershed soils. Thus, soil moisture in the Metamora sandy loam serves as an "indicator" of soil moisture in the other soil types on the watershed and as such gives a relative measure of over-all soil moisture for the watershed. 116 13.: 3.6 mm: 8% mmé .93.: min 8.: 320. mm.” .3. 33523 me.~ :m.: n:.~ 8. .84 3:92 2...: Nee m:.: on: SA has» «0.: 2...» 3.: mm: tum 2E. mm 84. dd . S.m 3.: as. a} .84. gm :1} 13.: 2.5 3.: no.” :05 mud no.6 nose: .. home: onwwmbu mo honed." .. Node—soc 50H Esq.” house do» ozoauoa Essa mono: 8am .230:an hoses oaofiomo .3 human 0% 53V “Ban: RS .52. 38 mm .813 mm: on - o zomemm eszome an. 958 £30: .38 amaze: 34mm: mu Ema. 117 TABLE 16 CORREIATION BETWEEN SOIL MOISTURE CONTENTS OF WATERSHED SOILS Soil types compared Correlation coefficient Metamora sandy loam and Miami loam .911" Metamora sandy loam and Hillsdale A” sandy loam .98 Metamora sandy loam and Hillsdale sandy loam-Mates sandy loam a complex .91.. Metamora sandy loam and Conover loam o 95*. "Significant at the one per cent level. Evapg transpi ra ti on Evapotranspiration refers to the removal of water from the soil by evaporation (usually the surface feat) and trans- piration (throughout the depth.of effective rooting). Evapo- transpiration constitutes the major depleting agent of availa- ble soil moisture. The importance of evapotranspiration to hydrologic research.is immediately apparent. By removing available soil moisture, retention storage is created and this in turn affects detention storage, because retention storage must be satisfied before water can go into detention storage. This concept is important in flood control efforts. 0n the other hand, reduction of transpiration losses by vege- tative manipulation would tend to increase water yield from 118 an area (Bill, 1953). Hoover (191111), in a study in the southern Applachians, reported that cutting all forest vege- tation increased water yield by an amount equal to the esti- mated transpiration. Computed evapotranspiration values for hetemora sandy loam are presented in Table 17. Average daily evapotranspi- ration for the period of June through September was lower during 1952 than during any other year of the study. Also total monthly evapotranspiration was lower for the same period. To determine whether the average daily evapotranspiration values were significantly different for the individual years of the study the data were subjected to an analysis of vari- ance. The analysis indicated a significant difference (five per cent level) between years (Table 18a). To determine which years differed significantly, the data were analysed by means of the I'studenti zed range" procedure. The results, Table 18b, indicate that average daily evapotranspiration during 1952 was significantly less (five per cent level) than for 19147, 19119, and 1950. Only one other significant difference was detected, that being between 19116 and 1950. The above analyses indicate that 1952 evapotranspiration values were lowered, presumably because of vegetative treatment. Appar- ently vegetative recovery was nearly to pre-treahnent status by 1957, as evapotranspiration values were not significantly different from pre-treatment years. 119 TIBLE 17 AVERAGE DAIIX AND 1401mm: EVAPOTRANSPIRAuou DURING JUNE - SEPMBER, 19116 - 1952 AND 1957 . Inches er da __A Y‘” “—735. mam..- "°"8° 19116 .13 .16 .08 .03 .10 19117 .11 .11; .26 .10 .13 19118 .16 .17 .12 .07 .13 19119 .15 .22 .13 .10 .15 1950 .m .22 .20 .11 .17 1951 . 11 .16 .15 .07 .12 7;;;;;;2 """ Ii£"""'316'"""Ii€"’“"265"""”Ii£" "i§§£""""36§'"""Iii?'""'Ii£"""’36i'"""'356" 1957 .12 .19 .11; .05 .12 ‘153hesvper7month 19116 3.98 11.8.3 2.37 1.03 3.05 19117 3.31 11.118 8.06 3.26 11.78 l9h8 17.71 5.113 3.69 2.26 11.02 19119 11.15 6.98 3.911 2.911 11.58 1950 17.20 6.70 6.09 3.111 5.10 1951 3.33 11.95 11.62 2.19 3.77 ‘;;;;;;; """ E IIS""”§I§£"‘"I???”'52Ei"""’£2§£“ "i535“"mi236 """ 3252 """ £255 """ i251} """" 5'33" 1957 3.18 p 6.03 1.1.; 1.65 3.90 120 TABIE 18 ANAHSIS OF' VARIAME 01“ AVERAGE DAIIX EVAPOTRANSPIRATION VALUES Source of Degrees of Sums of vgp1.t1°n froodan squares 'Heen squares F 'l'btal 31 .0913 * 3°33" 7 .0213 .0030 2.73 Months 3 .ogfig .0153 Error 21 . 1 .0011 b STUDENTIZED RANGE ANAHSIS 19h6 19h? 19h3 19h9 1950 1951 1952 1957 19h6 - NS“ NS NS Sb NS NS NS . 19h? - NS NS NS NS 3 NS 19u8 - NS NS NS NS NS 19h9 - NS Ns S NS 1950 - NS s NS 1951 - NS NS 1952 - NS 1957 - ‘Not significant at the five per cent level. bSignificant at the five per cent level. 121 In a study reported by lull and Axley (1958) in New Jersey, evapotranspiration values were computed, in a manner similar to that used in the present study, for various cover types, including a thirty-two year old stand of black and red oak. Average daily evapotranspiration, as computed by Lull and Axley, during June and July was .13 inches per day (0 - 5 foot depth), while the average daily rate for‘the same period in this study, prior to treatment, was .16 inches per day (0 - 3 foot depth). The greater evapotranspiration rates reported in the present study are , perhaps, attributable to the age of the pre-treatment stand which was approximately twice the age of the stand reported on by lull and Axley. Soil Temnrature Regime Soil temperature is one of the more dynamic physical properties of the soil. According to Savor (1956), "Soil temperature is one of the more important factors that control microbiological activity involved in the production of plants." It is well recognised that the rate of organic matter decompo- sition increases with temperature. The role of frosen soil in hydrologic studies is also recognized. Soils containing concrete-type frost are , for all practicable purposes, imper- meable to precipitation, thus promoting maximum surface run- off. The temperature of the soil depends primarily upon the amount of radiant energy received from the sun. The vegetation 122 of an area exerts a major effect on soil temperature by inter- cepting a considerable portion of the sun's radiant energy. The principle effect of forest vegetation on soil temperature is that of amelioration, i.e. reduces maximums and increases minimums. Consequently, the alteration of the vegetative cover of an area should considerably affect soil tasperatures. Because air temperature immediately above the soil surface (six inches) is so intimately connected with soil temperature it is appropriate to discuss soil and air tasperature trends together. Mean monthly soil and air temperatures for the period 19146 through 1956 are listed in Table 19. Average pro-treat- ment soil and air temperatures generally exhibit recogni zed trends. Soil temperatures were higher than air temperatures from September through February. Soil temperatures were lower than air temperatures from March through August. The most apparent effect of hardwood forest on soil temperatures is exerted during the growing season, when the foliage inter- cepts considerable radiant energy. The reduction of the forest canopy resulted primarily in increased maximum soil and air temperatures (six inch air and one inch soil) during the stunner months. V Table 20 indicates the effect of vegeta- tive treatment on air temperature six inches above the soil surface. Air temperature at six inches equaled or exceeded 90'? only twice prior to treatment, while after treatment 123 6.m: 6.:6 6.6m 6.6m :.6m 6.66 6.66 6.66 6.66 6.6: 6.66 6.66 6.66 .6 6.:: 6.66 :.mm 6.66 6.66 6.66 6.66 6.6m 6.66 6.6: :.nn 6.6m 6.66 .6 6.6: 6.66 6.66 6.66 6.66 6.:6 6.66 6.66 6.66 6.6: .66 6.66 6.:6 .6 6666 6.6: 6.66 6.~m 6.66 6.66 6.66 m.m6 6.66 6.66 6.6: .66 6.66 :.mm .m.: 6.6: 1:6 613 6.66 6.66 6.66 :46 6.66 6.66 «.66 6.66 6.66 :.:n .6 6.m: 6.66 6.6: 6.6m 6.66 ~.~6 6.66 6.6m m.:m 6.6: 6.66 6.66 6.~m .6 m.n: 6.66 «.66 6.6: 6.:m m.~6 6.66 6.6m 6.66 “.66 6.66 6.66 6.66 .6 6666 6.6: 6.66 m.mm 6.66 :.66 6.:6 6.66 6.66 6.66 .6: 6.66 6.66 6.66 .m.: 6.6:. 6. m 6.6: 6.6 6. m «.66 6.66 6.6m :.mm 6.6: «.66 6.66 6.66 6 6.6: 6.mm m.66 :.mm :.mm 6.66 6.66 6.66 6.6m N.:: 6.:6 6.66 ”.mn ”a 6.6: 6.66 6.66 m. 6.66 6.66 6.66 6.66 6.66 .6 m.:n :.- ~.:~ .6 6:66 6.6: 6.66 6.66 6.6: 6.6m 6.66 6.66 6.66 6.66 6.6 6.66 ~.m~ n.6w .m.: 6.6: 6.66 6.: 6.66 6.66 6.66 6.66 6.66 6.66 :13 36 6.6.... 6.66 .6 6.6: 6.:m 6.m: 6.6: 6.66 6.66 6.:6 6.6m 6.:m 6.6: 6.~m 6.6~ 6.66 .6 6.6: :.m~ 6.~: «.6: 6.:6 6.66 6.66 6.66 m.wm 6.66 6.6m 6.66 6.~a .6 6:66 6.66 6.66 6.6.6 6.6: 6.66 6.66 6.66 6.66 6.66 6.66 «.66 6.6... 3.: .61. 6.6: 6.66 6.x“ 6.66 6.66 6.66 6.66 6.66 6.6: 6.66 6.66 6.66 6.66 .6 66 66 6. 66 66 66 66 66 66 66, 66 66 66 .6 6.. 6.:: 6.66 6.66 6. m n.6m 6.66 6.66 6.66 :.mm 6.:: 6.66 :.66 6.66 ”6.: 6.6: 6.6: 6. : 6.:6 .66 6.66 6.:6 6.6m 6.6m 6.:: 6.6: «.66 :.mm 6 66 66 66 66 66 .6 66 66 66 66 66 66 66 66 .6 6.66.: 6.66 6.66 6.16m 6.3 .66 «.66 6.66 6.:6 6.66 6.3 6.66 6.8 “We. a! Pasha—sham.“ neonmen 666.6 .5 n z n m 6 h h s a m m h .8 a...» .6666: 6666.6 66$ .. 6:3 6655666656.. 6: 92 .366 56.626: 6.6.6: on names .ecsunsu 6606 on» rodeo nonon6 N66 enspeneQEep H6060 .eosuane 6606 on» rodeo soda one ensusnenaea Haome .ecsuana 6606 on» e>ons aenona H66 as eaoueneasep 66‘s .ecsunoe 6606 on» e>ons peek m.: as easusaemaou 664|£om .mg 23.3: o m < h. h. 2 ¢ 8 h h k \P b r P L L. -00 1.00 (q'tequeaqeg seeasea) eameaedmm 127 .mmoa 393390933 has one .30- hanuaoe omeaebdnfiow .93 323: Q a o m 4 h. h 2 d z .m h. 5 n n D r b p I- p p monafla o .Hdom III: 33 a .38 2.... w 8:3“ o £2 ll ./ . ., . .2. poo.“ m.: .34 ll: /.ll.\ (atequemed sooasea) eameaed‘mem 128 .mmod .eeagaaaaop can one :2. hang—03 owaao>«-.uo~ .mam guano: a z o -m < a a z 4 z a n L noses“ o .Haom -lc: good a .Haom -;sc nonona o .Aad .11: ”OOH Me: afid¢ I, (qthueaqeg eeeaseq) eanqeaedmem 130 .omwa .uonspmnoasop nHa cad HHOn hanuaoa emaao> u u h u \ \ I O N nonoaH 0 .HHom (.1: n2: H .38 :ii . .. .17.} monocH o .hH4 III. /!:I 38 m3 $3. I '5 5 <3 8_m.-.-rm (arequeaqeg seesfieq) eanquaedmem \ U 0 :5 I O D 131 temperature at six inches was considerably greater than all other temperatures from April through October. The six inch soil temperatures, on the other hand, were consistantly lower than all other temperatures throughout the year. 3011 temper- ature at one inch was higher than air temperature at h.5 feet during winter and was approximately equal to air temperature throughout the warmer months. The year 1953 exhibited a trend similar to 1952, with.six inch air temperature exceed- ing other temperatures by an even greater margin. This may be the result or increased ingrowth.or lesser vegetation, with a consequent reduction in air circulation at the six inch height. During l95h soil temperatures generally exceeded air temperatures throughout the year. This represented a complete reversal of temperature trends for the two proceeding years. By 1956, soil and air temperatures had returned to a pattern.similar to pre-treatment, i.e. soil temperatures were warmer during the winter and cooler during the summer than air temperatures. In general, minimum soil and air temperatures were not reduced, as a result or treatment, with the same magnitude as :maximums were increased. Perhaps the overall result or the increased maximum temperatures was manifested in the increased oxidation.or organic matter, as indicated by the reduction in total unincorporated organic matter and increased soil organic matter. 132 Hydrologic Studies The watershed, as a natural unit, reflects the inter- actions of soil, water, and vegetation by providing a common end product, runoff, which.enables the net effects of these interactions to be measured and evaluated. Runoff is a recog- nized criterion of watershed conditions and also of the effectiveness of watershed.management. One of the basic premises of watershed management is that the amount and rate of stremmflow expresses the natural and cultural character- istics and conditions of the watershed which produces it. The quality of runoff, which in this study refers to silt content, is also indicative of the effectiveness of the vege- tative o0ver in protecting the soil frmm erosion. This aspect of the study is concerned, therefore, with detecting any variations in runoff behavior as a result of the vegetative treatment applied to the watershed. Runoff The term "runoff”, as used in this study, refers to water leaving the watershed as surface flow, measured at the gaging station. As indicated above, runoff represents the net result of the interaction of the various factors affect- ing the disposition of precipitation on a watershed. Under relatively static conditions of vegetative cover and land use certain runoff patterns are established in conjunction with precipitation patterns. When, however, the vegetative cover 133 'or'type of land use on.a watershed is altered the relative degree of interaction of factors affecting the disposition ‘of'precipitation is frequently disrupted. The result is often Ihanifested as changes in the runoff patterns of a watershed, such.as changes in the average annual runoff, average monthly V runoff, frequency of runoff, and rates of runoff. In order to attain any degree of validity in comparing runoff behavior before and after treatment runoff values must be compared with.precipitation received on the watershed. IMonthly and annual precipitation and runoff values for the years l9hl through 1957 are given in Table 21. Average annual precipitation during the pre-treatment period was 32.6h inches and average annual runoff for the same period amounted to 0.5h inches. There appears to be very little correlation between annual precipitation and annual runoff. During the post-treatment period average annual precipitation was 30.37 inches while average annual runoff was 0.19 inches. The use of average annual runoff for the post-treatment period does not represent runoff under static clearcut conditions, but under a changing, increasing vegetative cover. The proportion of runoff to precipitation was less for the post-treatment period than for the pro-treatment period. Annual pro-treat- ment runoff constituted 1.65 per cent of annual precipitation, while for the post-treatment period annual runoff was only 0.62 per cent of annual precipitation.v While the average mHo. o o o a .H. o o o o c He. a e:.~m ee.: mo.H pa.H ~o.~ oo.~ ha.n m:.m oH.~ mo.~ m~.m o:.~ m~.n a ozeH Hm.H o o o o o o o m:. o mm. o o a am.e~ ~m.~ He.~ so. 3H.~ mm.H m~.~ oe.n m~.: HH.~ no.3 :H.~ eH.H m mzeH as. o o o o o o o :5. o o o a oH.en mm.H o>.H oo.m oo.m mm.m Ho.~ Hmtn m~.: m~.m :w.H Ha. :~.m m azeH so. o o o o o o o o so. o o a mo.nm «me ~ oa.H mH.~ Ha.H 0H.H mH. he.n eo.n on. oH.~ :m.H me.H a oaoH oo. o o o o a o o me. o o o o a ~:.mn mm.H Hm.H oo.a -.n mH.o may: oe.m H~.a oe.m eH.~ pH.H Hz. a mamH oo. o o o e e o mm. o mo. o o a mr.m~ nHo H oo.~ we. oe.~ o~.n no. oo.H o~.m Hm.H me.~ so.H -.H m asaH m~.H o o o o o o NH.H on. o mm. me. o a 8.3m Ha. oo.H mm.H a:.m Ho.: mm.~ am.m ~m.o mm.~ mo.~ a:.H o~.m m memH ea. o o o o o o o c on. o o .a HH. an wo.m o:.m on.a 0H.m oo.~ -.: oe.m oo.: or. mo.: at. ao.~ a memH e o o o e o o o o o a ea oa.m~ m:.H :~.~ oH.~ Hm.~ on.n oe.o oe.~ um.~ am.H o~.H . o- as HeeH .HoeH .oon. £03 2.30 .wnem .wo< hush 2.3m he: .ann 3m: .Pon .nen nee ergo: a am as Ml. Lt amoH - Hon .aaozom oz< onagaHmHummm_H¢ a o o o o o o o o o o o e a :~.~m oo.~ ha.~ H~.: ms.~ :m.m H:.H NH.m eo.m om.m op.H om.H mm.m m HmeH or. o o mH. o oH. am. mo. 0 mm. on so. H «H. on oe.H :o.n oz.n m~.: :e.: um. N Ho.: oo.~ oH.m mm.m a omoH .Peo .pnbmr .wHE has...” omen he: 33¢ 33: .mon .nsn as e H 136 .Hdofl .nOHqudnunz phwvm pofl vac noncomh HHQQSH 6nd floauau«QH00hn Addeduhoo .uuoaamn .aoHpapHaHooamu oH. o o oo. oo. :o. o o c .>¢ hm on fihoa ”mo N wwo N @:.H :N.m me.m odom moon mo.m QH.N po.m mm.n m .009 .bmzl‘.»MD .unom .wad hfizn an gm .had hue» .1, npnoz Avoznaanoov Hm flumsE 137 annual post-treatment precipitation amounted to ninety-three per cent of that of the pre-treatment period, average annual post-treatment runoff amounted to only thirty-five per cent of pro-treatment runoff. From a consideration of average annual precipitation and runoff before and after treatment the study indicates there was less annual runoff after treat- ment than before. Over the period of study, runoff occurred predominantly during the months of March, April, May, and June both before and after treatment. During the period of study, l9hl through 1957, a total of forty-four runoffs occurred, with thirty- three of these occurring within this four month period. On examination of the soil moisture graphs presented in the section on soil studies, it is apparent that this four month period represents a period of maximum soil moisture storage with very little storage space for additional moisture. Con- sequently, when additional moisture was received as snowmelt and/or rainfall the available storage was quickly satisfied and the remainder of the water went into runoff. Since this March through June period represents very little vegetative activity and the bulk of the annual runoff, the effects of removing the vegetative cover on runoff was minimized. No measurable amounts of runoff were recorded during the period of July through December prior to treatment. However, during August 1952 a runoff of 0.0028 inches was recorded. Again, Qt _._ y, 138 on examination.of the soil moisture values for 1952 it is seen that the established pro-treatment period of soil moist- ure depletion during July and August did not occur during 1952, thus providing a minimum of storage opportunity fer additional precipitation. This minimum of water storage opportunity, together with above normal precipitation during August produced this small runoff noted. Thus, it appears that this runoff may be attributable to vegetative treatment. The frequency of occurrence of runoff, presented in Table 22, does not indicate any particular trend attributable to the effect of clearcutting the watershed. There was an increase in the frequency of runoffs during April and.Hay of 1956, and during July of 1957. ’This increased frequency of runoff occurred five and six years, respectively, after treat- Inent and after a dense vegetative cover had been established on.the watershed. An above normal amount of precipitation during these two periods is perhaps the reason for the increased frequency of runoff. The amount of precipitation recorded during July 1957 exceeded any amount previously recorded for July during the period of study. Precipitation and runoff for individual storms causing runoff during the period of study are given in Table 23. The average amount of precipitation and runoff per storm during the pre-treatment period (from January through April) was l.h3 inches and 0.2177 inches respectively. For the post- 139 TABLE 22 FREQUENCY OF RUNOFF, 191,1 - 1957 _ AAA Months Years 'TTMATIT'J—T'Tm—Toul 19141 --l--------- l l9u2 - - 2 - - - - - - - - - 2 19h3 - l l - 1 l - - - - - - h l9h5 - - - - l - - - - - - - l l9h6 --1---—----- 1 191.3 ---1-------- 1 1934 --1-1------- 2 191.9 1--’---11---- 3 1950 - l 2 2 - 1 - - - - - - 6 1951 l - - - - - - - - - - - l ----- ------------------ - ------ Treatment-~------------------- 1952 - - - l - - - 1 - - - - 2 {9&3 l - l - - - - - - - - - l 9 - - - - - - - - - - - l 1955 --1--------- 1 1956 ---u3------- 7 1957 ----1-3----- h Total 3 2 12 8 8 2' u 2 hl treatment period the average amount of precipitation per storm 'was 1.83 inches and the average amount of runoff was 0.10h9 inches (also for the interval of January through.April). iRunoff for this portion of the year includes snowmelt as well as rainfall. Average precipitation and runoff per storm during May throuthAugust for the pro-treatment period was 2.36 inches and 0.hh9h.inches respectively. For the post- treatment period (also for the interval of May through.August) TABLE 23 1&0 PRECIPIIMTION AND RUNOFF FOR INDIVIDUAL STORMS, 19h1 - 1957 Date Precipitation Runoff - inches - 3 - 13 - 111 093 00038 3 - 9 - h2 1.8u .1368 3 - 18 - h2 2.31 .6539 2 - 23 - h3 .15 .033 3 - 15 - h3* 1.01 .2505 5 - ll - h3* 1.68 .3030 6 - 2 - h3 2.75 1.1698 3 - 15 - an .52 .0159 E' :3 ' kit» at? '28:; s - 15 " “5* 2.12 .0 3 " 6 ' ’46 093 e0726 '4. - 6 ' ’47 2095 07397 g : :3 :11. 6:22 :32 a 1 - 1213* L22 .0... 8 - l6 - 19* 1.08 2 - 1h - 50 1.77 .0170 3 - l - 50 .5 .17h8 3 - 28 - 50 1.12 .0957 h - h - 50 1e65 .1098 h. " 25 ‘ 50 2017 00652 6 - 3 - 50 2.73 .1329 1 ' 20 - 51 .31]. T ---- Treatment -- h - 12 - 52 1.80 .0511 7 - 1 - 52 1.80 .0028 1 - 2h - 53 .71 .0209 3 - 25 - 5h 1.55 . l a - ‘2'- ‘ gz .53 .1025 h - 27 - 56 2.13 .0536 h - 29 - 56, 3.20 .2575 5 - 6 - 56 1.11 .0960 5 - 10 - 56* 1.86 .2391 S "' 13 - 56* 1.21 .1200 5 - 19 - 57* 1.77 .0921 7 - 3 - 57* .19 0010 7 - " 57* 2.19 .00112 7 - 11 - 57* 2070 .0008 *Precipitation entirely in the form of rain. - 1111 average precipitation and runoff per storm was 1.60 inches and 0.0695 inches respectively. In each instance, i.e. for the January through April period and the May through August period, runoff amounted to a smaller percentage of precipita- tion after treatment than before treatment. 5‘ Maximum rates of discharge are often indicative of : ~ effects of vegetative treatment. Table 211 lists the maximum rates of discharge experienced per year for the period of study. Ranked in order of decreasing magnitude, the five max- imum rates of discharge for the period of study occurred dur- ing the pro-treatment period. Average annual maximum rate of discharge was also greater during the pro-treatment period. The average maximum volume of runoff per menty-four hour period prior to treatment was 0.1120 inches, whereas after treatment the average maximum twenty-four hour runoff was 0.135 inches. The average maximum runoff volume for a one hour period before treatment was 0.1117 inches as contrasted to 0.0115 inches after treatment. The results of the study indicate rates of runoff during the post-treatment period were less than during the pro-treatment period. infiltration Infiltration refers to the entry of water into the surface of the soil and as such is entirely a surface soil phenomena. After the water enters the soil surface the sub- sequent movement of the water through the soil profile is a .‘2 F TABLE 21 MAXIMUM RATE OF RUNOFF PER YEAR, 1911 - 1957 _1 I D‘t° Inmfiggggéé‘fiour 3 - 3 - 11 .003 3 - 16 - 12 .070 6 - 2 - 13 .110 5 - 21 - 11. .2h0 5 - 1h - 15 .020 3- 5-16 . .010 h - S - h? .100 3 - 19 - ha .210 1 - 18 - 19 .003 6 - 2 - 50 .020 1 - 20 - 51 T 1 - 12 - 52 .010 1 - 19 - 53 -* 3 - 25 - 51 .010 3 - 3 - 55 .020 5 - 13 - 56 .050 S - 18 - 57 .009 *Record lost. 1’43 function of soil permeability. Prior to the soil profile becoming saturated, the infiltration rate is the prime factor affecting the disposition of precipitation into surface runoff or subsurface movement. Only when the rate of precipitation exceeds the infiltration rate can surface runoff occur. Average infiltration rates determined for the entire watershed by analyses of hydrographs for storms occurring during the growing season, before and after treatment, are summarized in Table 25. The study indicates that the average infiltration rate (fay) per storm.after treatment was greater than prior to treatment. Perhaps this slight increase in infiltration rate may be attributable to the decreased depth of unincorporated organic matter, as indicated in the section on.unincorporated organic matter. Hursh and Hoover (1911) found from an infiltration study of an undisturbed forest soil profile, that approximately 2.5 per cent of artificial precipi- tation applied ran off as surface runoff because of the shingle effect of hardwood litter. Erosion The amount of soil removed from a watershed by surface runoff is indicative of the condition of vegetative cover and land use. A certain.amount of erosion is taking place con- stantly on any given area and is referred to as normal or geologic erosion. The intensity of normal erosion is governed primarily by such factors as topography, geology, soils, . ”1M l... . U E ThBLE 25 AVERAGE INFIIERATION RATE PER STORM DURING THE GROWING SEASON, 1911 - 1957 Average infiltration rate Date (inches per hour) 5 - 11 - 13 Pro-treatment .138 6 - 2 - 13 .232 S - 11 - 15 .170 5 - 10 - 18 ‘ » .112 6 - 2 - 50 .226 """ 1-13;;-..----------..--....-----------:§l.;.1.----------- .. m"'2':ITEW"ESQZIZQEZQSQE' ‘‘‘‘ -:;:---------- 5 - 9 - 56 .123 5 - 13 - 56 .160 5 - 18 - 57 .09h 7 - h - 57 .398 7 - 8 - 57 .53h 7 - 11 - 57 .50h """ ””'Z;2;2§;"""""""m"m""WESTWM'" _ climate, and vegetative cover. The disturbance of vegetative cover, with the attendant disturbance of litter, frequently accelerates the rate of erosion for a particular area. The total erosion from the watershed for the period of study was 11.7 pounds per acre, with 62.0 pounds per acre 1115 (over eighty per cent of the total) eroded prior to treatment (Table 26). Nominal amounts of erosion were noted during 1952 and 1953, the first and second years after treatment. Apparently the treatment had no significant effect on erosion from the watershed. No increase in erosion could be expected since the amount and rate of runoff decreased slightly after treatment. Hydro logic Summagy Precipitation, runoff, and erosion values are summarised in Table 26. The data are presented graphically in.Figure 21. The hydrologic data obtained in this study do not, indicate any pronounced effects of vegetative treatment on the hydrology of the watershed. Only on one occasion was runoff thought to be attributable to the effects of treatment, i.e. during August, 1952. The results of this study are contrary to opin- ion put forth by Smith.and.0rabb (1953) in reference to antic- ipated treatment effects on the wooded watershed. Smith and Crabb stated: In light of this tentative and preliminary analysis of similar storms under different cover conditions, it is anticipated that the removal of a timbered cover will have a profound effect upon the absorption of precipita- tion by a watershed. Runoff will be probably occasioned by storms having smaller intensities and totals of pre- cipitation, and erosion losses will be consequently greater. It appears that lack of treatment effect on runoff and erosion may be the result of insufficient disturbance of 1116 new- i w m.~a eemo.e me.nHe m.: memo. oo.:~ mmeH «.66 eoHo.e em.omm «.6 ommo. ao.o~ «moH -----mm..-------$w~..w----mmmm-----§a...a.:-m:-----m...mm--:--mm-: o.~e meeo.m op.»~m o.em «pom. «n.6m omoH ~.~m epon.m n:.mmm eHHo. 6:.um memH ~.am memm.m ~¢.mm~ «.aw oan.H em.e~ meoH ~m:o.: 6:.emm pane. m~.en pemH mnon.n se.aoH emeo. em.nm eeoH oom~.m 65.neH come. ~:.mn memH nomH.n an.m~H comm. me.m~ AeeeH :Hmm.~ ea.66 oema.H 66.:m meaH weep. ma.:e Foes. HH.am memH omoo. :e.»~ once. . :e.a~ HeeH Aeaoe\. up: :30qu 30:33 Aeaee\ . 3.: Agnes: :23qu aoaeonm mm 055 . 3009b uoHeoa on: . o ca 333 3.335250 :33 game» .Heew ameH . HaoH .mmexzem oHeoHomoam em memes 1h? auww - 1.1:. new; £23m . 88.. Sen amt n.3e sumo.» He.mom ~.~ weep. «3.0m emmH m.~a Nee~.e we.m~: mmoH. se.e~ mmmH m.-. wmmao 18.3.3 .313. QTmm :mma Aeaefi\.endv AmenenHv Aeeneadv Aeaes\.unav AeeneoHv Anemonav nowmoam tog—F .93me noueoam mm 95m .oaoeMnl .Heew eaepoo eoHeoazaoo naepoo Haas» AoesanuooV ow mange .wmoa 1 "Jon .oeneaeoea oooooz on» no» haeasoe eHmoHoaohm1.Hm .wwh amoH emmH mmeH emoH nmoH mmeH HmeH omeH meeH meoH weeH eeeH meeH eeoH neeH memH HeeH O 2H.> HM _ _ _ Q63 30H 38 opasque 1...: _ _ _ 3. § I .3. (040v7'cqt) 'IOI'IIOS - (009091) Izouna one noranatdtooaa _ :oaoeoaaaoeam e>Hpuaano 1 8 A: -oom :F.~:m uncaneeAespeom _ aneaueeaonenm 1119 unincorporated organic matter on the soil surface. Lowdermilk, 22. cit., summarizes this point quite clearly: No significant differences can be expected in experi- ments when the absorption conditions of the soil surface are not changed, even though.the forest is cut off. Such differentials as would arise under these circum- stances are referable to differentials in the intercep- tion and transpiration of different types and ages of vegetation. The chief condition, then, which is necessary to produce differences in the regimen of run-off and erosion, is feund to be complete removal not only of the mantle of vegetation but particularly of the natural layer of litter. CHAPTER VII SUMMARY AND CONC IUSIONS Because of the increased interest manifested in the water resources Of southern lower Michigan it is highly desir- F\ able to ascertain the water yield contributions of areas under _ various types of land use and vegetative cover. There are approximately 1.1 million acres of farm.woodlots in southern lower Michigan on which the commercial-type clearcut is the ‘most common type of timber harvest. The purpose of this study is to determine and evaluate the effects of this type of har- vest cut on soil and water relations on a mmall wooded water- shed representative of the farm woodlot-type. The Study A small wooded watershed, located on state-owned lands in southeastern Clinton County, was established during 1911. The watershed, supporting a well stocked.stand of the oak- hickory type, was calibrated hydrologically for an eleven year period. During the latter part of 1951 and the early part of 1952 the forest cover was subjected to a commercial- type clearcut Operation, removing all trees larger than 5.5 inches d.b.h. Hydrologic data were also obtained through 1957 . 151 Detailed soil sampling for soil physical property determinations was undertaken on the watershed during 1953, 1957 and on the adjacent uncut area during 1957. Gravimetric soil moisture sampling was initiated during the latter part of 1915 and continued on a bi-weekly basis through 1952. weekly soil moisture samples were obtained from March through September of 1957. These pedologic and hydrologic data were obtained in an effort to determine and evaluate the effects of the vege- tative treatment on the soil reservoir and the water yield of the watershed. Findings of the Study 3.9.1.12 The texture of the surface soils on the study area ranged from sandy loam to loam, while the subsurface textures ranged from sandy loan to silty clay loam. As a result of this study a soil formerly classified as Conover silt loam was tentatively reclassified as Metamora sandy loam. No changes in soil texture were noted as a result of the vegeta- tive treatment. Bulk density values for the upper six inches of soils on the watershed were slightly lower during 1953 than during 1957. The watershed soils exhibited consistently lower bulk density values than the similar soils on the adjacent uncut 152 area during 1957. There is no indication of a pronounced change in soil bulk density as a result of treatment. Poros- ity values were fOund to be generally favorable for water storage and.movament in the surface soils. There is no indi- cation of change in total porosity or relative proportions of capillary and non-capillary porosity as a result of treatment. Percolation rates were feund to be adequate for water drainage within the upper foot of all soils, but were definitely restricting below twelve inches in most soils. .Again, there is no indication of a change in percolation rates as a result of treatment. Loss on ignition values, which are indicative of relative soil organic matter, were higher in the soils of the treated area than in the soils of the untreated area. The results seem to indicate that the treatment has increased relative organic matter content Of the watershed soils, per- haps as a consequence of a change in litter type and a more rapid rate of oxidation of unincorporated organic matter resulting from higher air and soil temperatures. The amount of unincorporated organic matter on the surface also appears to have been affected by vegetative treatment. The untreated adjacent area contained more than fifty per cent more unin- corporated organic matter than the treated watershed area. This reduction of unincorporated.organic matter appears to be related to the increased soil organic matter content in the watershed soils. The physical prOperties of the soils do not 153 appear to have been impaired by the vegetative treatment applied to the watershed. A study of soil moisture regime before and after treat- ment indicated a very definite and statistically significant increase in soil moisture during the growing season of 1952 as a result of treatment. This increase was noted for the entire profile, to the depth sampled (0 - 36 inches), as well as for the individual depths sampled. Available soil moisture remained at a very high level throughout the 1952 growing season. However, during the 1957 growing season soil moisture values were intermediate between the extremely high values of 1952 and the average pre-treatment values, indicating a re- establishnent of the vegetative cover towards pre-treaunent conditions. Evapo transpiration values, computed from soil moisture data, were lower during the 1952 growing season than during the pro-treatment period or during 1957. The 1957 evapotrans- piration values fell within the range of the pre-treaunent period values, indicating the dense regrowth on the area con- sumes nearly as much soil moisture as the original forest cover. Mean soil and air temperatures were generally increased as a result of vegetative treatment. Maximum temperatures were greatly increased, perhaps resulting in increased rates of decomposition of unincorporated organic matter. 1511 Hydrology Average annual runoff, expressed as a percentage of average annual precipitation, was found to be less after treatment than before treatment. Likewise, average monthly runoff values were lower after treatment than befbre. Since $1 the majority of the annual runoff occurs during the spring 6 when snowmelt and saturated soil are prevalent, the opening up of the stand to increased solar radiation and.wind movement may have enabled a more rapid rate of sublimation of snow and increased soil moisture evaporation. This reduction in runoff potential may have resulted in the slight decrease in runoff noted in the study. .Maximum.rates of runoff were also lower after treatment, as well as average volume per runoff. The frequency of runoffs was apparently not affected by the vege- tative treatment. The average infiltration rate per storm during the growing season, as determined by hydrograph analy- sis, was found to be greater after treatment. A hydrolOgic summary for the entire period of study indicated no significant change in the overall hydrologic characteristics of the watershed. However, there is an impor- tant, though.not obvious, implication of the study with respect to the water resources Of the area. With no apparent increase in runoff from the watershed and higher levels of soil moisture during the first year after treatment there were probably increased contributions to the ground water supply Of the area. 155 In conclusion, it may be said that though the comer- cial-type clearcut is not particularly desirable from the standpoint of forest management it does not appear to have had any deleterious effects on the soils of the watershed nor on the water resources of the area. LITERATURE CITED Ayer, Gordon R. 1919 A progress report on an investigation of the influence of reforestation on streamflow in State forests in central New York. U. S. Dept. Int. Geol. Surv., in cooperation with State of New York Conserv. Dept. 185 pp. ’ Axle , J. H. and R. P. Thom”. l9 8 Soil moisture as influenced by vegetation. Proc. Soil Sci. Soc. Amer. 13: 518 - 550. BatOn, V. Do and he He EiGmeiare 1951 A sunmary of weather conditions at East Lansing, Michigan prior to 1950. Mich. State 001. and Agric. 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Zon, Raphael. 1927 Forests and water in the light of scientific investi- gations. U. S. Forest Service. (Reprinted with revised bibliography, from Appendix V of the Final Report of the National Waterways Comm., 1912. Senate Document No. 169, 62nd Congress, 2nd Session.) 106 pp. . VA . ~4§""“‘M 0"- I ‘a- En. . £1 .1: 'A ,. ' ‘ ‘ ; - ‘< .» ' L ‘9 1 v i 5’ "Jig F’ ' 'u 131 ’ “cw- I I, . ’3... a a - 4 ,4 meta? -. . *3‘:1"1fi— ; ”g." ~._._n C ,l J‘ I MICHIGAN STATE UNIV. LIBITIMTIES mWIWWWNWIWII‘HIWIHINHIIWIIHI 31293100934540