WWI!“WINUHWWIH1\IHHIHHHHHNHI THESIS m l ’3: il/II/lllI/Ullll Ill/Hil/ll/I/IU(Ill/Ill”IIIIHI/l/flI/l/Hm 3 1293 10468 2491 ._..‘ Ji‘.‘ wen-"1'4; 3187" This is to certify that the thesis entitled ' DIAMETER GROWTH OF RESIDUAL STANDS IN LOGGED OVER AREAS IN EAST KALIMANTAN TROPICAL RAIN FOREST INDONESIA presented by Soekotjo has been accepted towards fulfillment of the requirements for Forestry Ph . D . degree in (Q? z. 7? %//f Major professor Date June 11, 1981 0-7639 MSU RETURNING MATERIALS: PIace in book drop to remove this checkout from rmtfl 75’} g Jigg 48 53.5319 19L: IJBR ARJES your record. FINES wiII be charged if book is returned after the date stamped below. ,_ fr”- Amfizz’ f o- 7', I‘Vugz’fif/ DIAMETER GROWTH OF RESIDUAL STANDS IN LOGGED OVER AREAS IN EAST KALIMANTAN TROPICAL RAIN FOREST INDONESIA By Soekotjo A DISSERTATION Submitted to Michigan State University in partiai fulfiliment of the requirements for the degree of Doctor of Philosophy Department of Forestry 1981 A C5//.{ ABSTRACT DIAMETER GROWTH OF RESIDUAL STANDS IN LOGGED OVER AREAS IN EAST KALIMANTAN TROPICAL RAIN FOREST INDONESIA By Soekotjo Modern exploitation in tropical rain forest of East Kalimantan, Indonesia started in l967. To regulate the cut on a sustained yield basis, growth data are needed. The goals of this study were: (I) to obtain information on growth rates of different species; (2) to evaluate how much competition of neighboring trees determines diameter growth; and (3) to determine how much release due to logging stimulate diameter growth. A total of 29 one-hectare permanent growth plots were located in recently logged over forests. Three years after establishment, diameter growth, basal area of tree's competi- tors, and distances from the opening were measured. For each species strong correlation between diameter growth and initial diameter; the greater the diameter, the greater the growth rate. Comparisons of growth rate among species were performed using a homogeneity test. There were differences in Y-intercept but not in the slope among red meranti, white meranti, yellow meranti and bangkirai. These four species belong to the genus Shorea. There were differen- ces among the slopes and Y-intercepts of genera Shorea, Dipterocarpus and Cotylelobium. Soekotjo The basal area of each tree's competitors was measured. The greater the basal area of the competitors and the greater the competition, the less the diameter growth. Logging reduced basal area and competition, thus increasing diameter growth. Tables were constructed showing predicted diameters 15, 25 and 35 years hence for trees of varying present diameter. From these tables, estimates were made of the numbers of trees reaching merchantable diameter (50 cm) in 35 years. According to these estimates, 9-ll trees per hectare will reach merchantable size in 35 years. Those numbers are almost the same as the number of trees cut during the original logging. ACKNOWLEDGEMENTS I would like to thank my major advisor, Dr. Jonathan H. Wright, for the counsel, guidance, encouragement and invaluable help he provided throughout my study at Michigan State Univer- sity, U.S.A. He served in dual roles as an advisor and friend. I also wish to thank Drs. Peter G. Murphy, Donald I. Dickmann, Victor J. Rudolph, and Susan R. Kephart. They served on my Ph.D. committee and reviewed my dissertation. Drs. Peter G. Murphy and Donald I. Dickmann also served on my M.S. committee. I am indebted to Gadjah Mada University, Yogyakarta, Indonesia, for providing me the opportunity to study at M.S.U., MUCIA-AID program for its fellowship throughout my study, and Yayasan Pembina Fakultas Kehutanan, Gadjah Mada University for its funding of research in Indonesia. My truthful appreciation is expressed to Mrs. and Mr. Suseno, Prof. Soedarwone Hardjosoediro, Dr. Achmad Sumitro, Dr. Setijono, Dr. Sunardi and Mr. Suwarno for their encourage- ment and support during my stay in the U.S.A. Appreciation is also expressed to Dinas Kehutanan Kalimantan Timur, P.T. ITCI, GPI and KRTP and their staffs for their generous support and cooperation throughout my research in East Kalimantan. ii For their kind c00peration in typing and assemblying of this manuscript, I am deeply grateful to Miss Debra North and Ms. Mary Schneider. Above all, I am grateful to my wife Siti Samsijah, our daughters Retno Agustina Ekoputri, Elida Nur Aini, Endah Nur Nulan, and our sons Agus Santoso Budhi, Prakoso Hadi Takarijanto, and Rachmat Pribadi for their constant encourage- ment, patience, tolerance and long suffering during my study and away from them. It is to her, our children and our parents that I dedicate this dissertation. iii TABLE OF CONTENTS LIST OF TABLES. LIST OF FIGURES INTRODUCTION. LITERATURE REVIEW THE Introduction. Mean annual diameter growth in .logged over and. uncut forests Growth related to crown position. Problems in measurement STUDY AREAS Location. Climate . Topography. Soils . Vegetation. Logging operations. METHODS Plot establishment and measurement. Data handling Computations. RESULTS AND DISCUSSION. Mean annual diameter growth Growth related to initial diameter. . Comparisons of diameter growth among species. Growth related to competition . Growth related to distance from the opening The application of growth data. . Estimating the amount cut in the next cutting cycle . . . . . . . Limitations of previous growth studies. iv Page vi viii Page SUMMARY AND CONCLUSIONS. . . . . . . . . . . . . . . 70 REFERENCES CITED . . . . . . . . . . . . . . . . . . 74 APPENDICES . . . . . . . . . . . . . . . . . . . . . 78 Table 10 ll LIST OF TABLES Mean annual diameter growth of dipterocarp species in logged over stands in Malaysia (MAL) and the Philippines (PH). Mean annual diameter growth by group of species in eight concessions in East Kalimantan (from Setijono 31 11., l979). . . . . . . . Mean diameter growth of undamaged trees 6 years after logging and of similar trees in unlcgged forests (from Miller, l980) Basal area increase by species as related to crown position (from Murphy, l970). Amount and distribution of rainfall in the three study areas (Directorate of Forest Inven- tory and Planning, l968, and ITCI unpublished data) . . . . . . . . . . . . . . . . . . Average number of trees per hectare by diameter class in the three concessions (from Soekotjo £1 31., 1976 and Setijono 31 31., l978) Average cut per hectare by group of species and total cut in last 10 years operation in the three concessions (from ITCI, GPI, and KRTP's working plan 1980-198l) . . . . . . Number and location of plots on the three concessions Instruction card using keypunch drum. Procedures used to calculate growth as related to initial diameter using TI Programmable 58 C. Procedures used to calculate student's "t" for testing difference between two b's, using T1 - 58 C calculator. . . . . . vi Page 13 20 25 27 29 38 40 42 Table Page l2 Procedures used to calculate the effect of basal area of tree's competitors on diameter growth of subject tree, using T1 58 C calculator. . . . . . 44 13 Mean annual diameter growth by species as related to initial diameter . . . . . . . . . . . . . . . 46 l4 Mean annual diameter growth data by species, in tropical rain forests of Zimbabwe, Guyana and Puerto Rico . . . . . . . . . . . . . . . . . . . 48 l5 Matrix of Student's "t" for b's for species of Dipterocarpaceae. . . . . . . . . . . . . . . . . 5l 16 The effect of competition on diameter growth. . . 57 17 Diameter growth of dipterocarps at varying distances from openings caused by loggings. . . . 58 18 Years needed for trees of given present diameters to atting future diameters of 350, 450 and 550 mm. . . . . . . . . . . . . . . 6O l9 Future diameter growth by species and diameter on permanent plots of logged over forests in the three concessions of East Kalimantan tropical rain forests. . . . . . . . . . . . . . . . . . . 63 20 Previous cuts and predicted future cuts after 35 years growth . . . . . . . . . . . . . . . . . 66 vii LIST OF FIGURES Figure Page 1 The location of I.T.C.I., G.P.I. and K.R.T.P. concessions in East Kalimantan. . . . . . . . . l8 2 The distribution of permanent growth plots in I.T.C.I. concession . . . . . . . . . . . . . . 3l 3 The distribution of permanent growth plots in G.P.I. concession . . . . . . . . . . . . . . . 33 4 The distribution of permanent growth plots in K.R.T.P. concession . . . . . . . . . . . . . . 35 5 The four parallel regression lines of red meranti, white meranti, bangkirai and yellow meranti . . . . . . . . . . . . . . . . . . . . 53 6 The regression line of keruing crosses regression line of yellow meranti and bankirai. . . . . . . . . . . . . . . . . . . . 55 viii INTRODUCTION Borneo is a large tropical island, located on the equator between Australia and Asia. Borneo belongs to two countries, Malaysia and Indonesia. The Indonesian territory is called Kalimantan. Kalimantan consists of four provinces: West, Central, South and East Kalimantan. East Kalimantan has an area of 202,000 km2 (89,700 miz), about the same size as the state of Nebraska. The forest of East Kalimantan is called "Tr0pical rain forest." The tropical rain forest of East Kalimantan covers about l72,000 km2 or about 85% 0f the total land area. Roughly 50% of Indonesian log exports are from this forest. Timber in Indonesia is the second most important resource after oil. Therefore, East Kalimantan tropical rain forest is the most important forest of Indonesia. Before l967, forest exploitation in this province was restricted to areas very close to rivers. In 1967 tractor and truck logging started. Roads were constructed to facilitate year-round logging operations. Since then, log exports have increased very sharply from 2.8 million 1113 in l967 to 19.4 million m3 in 3 T973 and l9.8 million m in 1977 (Forest Products Marketing Development Project, 1978). Logging is being done using a method called "Indonesian Selective Logging" (Tebang Pilih Indonesia). According to law "Indonesian Selective Logging" consists of removal of veteran and mature trees with diameter above 50 cm before they begin to stagnate and deteriorate. Approximately 25 young and healthy overstory trees are left per hectare. These trees should be well distributed spatially and of adequate economic value. After logging, stands are inven- toried 100% for exportable trees 20 cm diameter and up to determine the amount of damage. Regeneration inventory is done by linear sampling, one4m2 plot per ha. If less than 40% 0f the plots contain seedlings belonging to I exportable species, enrichment planting should be done. Enrichment planting is also suggested 0n skid roads and log yards of logged over areas. Tending to free regeneration from competition should be done as needed (Direktur Jendral Kehutanan, l972). Actually concession holders do not obey all rules of Indonesian Selective Logging. They only follow the diameter limit. The amount cut ranges from 3 to 22 trees per hectare. To date there are few data concerning the effects of logging on East Kalimantan tropical rain forests. Felling and skidding cause logging damage to 45% 0f the trees in residual stands. Logging damage is related to number and. basal area of trees extracted (Syachrani 33 31., l974 and Soekotjo 31 31., l976). However, logging may stimulate the growth of undamaged trees as demonstrated by Miller (l980). Sustained yield management of the forest requires a large amount of information from various fields. Such information is necessary if a company is to evaluate its operations and forecast future developments. Information on growth by species is especially needed. Growth data are basically needed to regulate the cut on a sustained yield basis. With sufficient and reliable growth data, the companies will be able to predict the quantity of wood that can be removed from a forest land within a given period of time. Tropical rain forest trees do not produce annual rings. Whenever growth rings are present, they are not clearly distinguishable and are not necessarily annual. It has been impossible to determine the rate of growth in this forest by stem analysis. The only method to determine growth rates is by establishing permanent plots in which the same trees are measured at intervals of time. As part of East Kalimantan Forest Service's long term forest management plan, Gadjah Mada University has esta- blished 79 one-hectare permanent plots. These plots were established directly after logging in 1977 in logged over forests throughout East Kalimantan. 'In l980, I reexamined 29 of these one-hectare plots. The objectives in my study were: (1) to obtain infor- mation on growth rates of different species, (2) to evaluate how much competition of neighboring trees determines dia- meter growth, and (3) to determine how much release by logging stimulates diameter growth. LITERATURE REVIEW Introduction In previous growth studies of dipterocarp forests both very slow and fast growth rates were reported. This varia- tion in growth rates arises from two reasons. First, the forests are extremely rich in number of tree species. This richness was reported by Poore (1968) in his study of Jangka forest of Malaysia. Within 23 hectares, he found 52 tree families. The most common families, each with 22 or more species, were Dipterocarpaceae, Euphorbiaceae, Myrtaceae, Burseraceae, and Lauraceae. With so many species, growth rates vary. Thesecond reason lies in variation in initial diameters. Comparisons of growth rates are complicated by the fact that initial diameter affects growth rate but is ignored in most publications. Mean annual diameter growth in logged over and uncut forests In Basilan working circle in Republic of the Philip- pines, five permanent growth plots were established in 1956 (Sulit _3 _1., 1962). Plot size ranged from 0.25 to 1 hectare. Three plots were located in old forests, logged over by the highlead system, and two plots were in recently cut areas logged with tractors. Plots were remeasured 4 years after establishment. Growth data ranged from very low to high. Diameter growth rates in excess of 10 mm per year were recorded for meranti almon and urat mata. The lowest growth rates were for meranti gisok and lempung abang (Table 1). In 1966, 20 one-hectare plots were established in northern Borneo by Fox (1970). Plots were located in forests logged over in 1957 and 1959 in Segaluid, Lokan, Sabah, Malaysia. The forest is typically lowland dipterocarp in which urat mata beludu, meranti merkuyung, meranti tembaga, kapur tanduk, and keruing tempurung are the dominant species, all belonging to the family Dipterocarpaceae. Measurements were made annually for 5 years. Growth data were reported by Wong (1973). Growth rates also ranged from very low to high. Diameter growth rates in exCess of 10 mm per year were recorded for meranti merkuyung and seraya melantai. The lowest growth rates were for balau putih and keruing tempurung (Table 1). In 1936, three growth plots were established in Negeri Sembilan, Malaysia. Plots were located 75 to 300 m above sea level. About 57 trees of seraya melantai were selected for growth studies. The last measurement was in 1956. Data were reported by Vincent (1961). The mean annual diameter growth for seraya melantai was 13 mm (Table 1). One large plot was established in 1939 in Perak, Malaysia. The plot was located at altitudes from 16 to Table 1. Mean annual diameter growth of dipterocarp species in logged over stands in Malaysia (MAL) and the Philippines (PH). Mean Genus and annual Province and Author species diameter country growth mm Anisoptera Mersawa 6 Basilan, PH Sulit _1 31 , 1962 Dipterocarpus Keruing tempurung 4 Sabah, MAL Wong, 1973 Keruing hijau 6 Basilan, PH Sulit 33 31., 1962 Dryobanalops Kapur tanduk 6 Sabah, MAL Wong, 1973 Parashorea Urat mata 12 Basilan, PH Sulit _1 31., 1962 Urata mata beludu 8 Sabah, MAL Wong, 1973 Shorea Meranti almon 12 Basilan, PH Sulit 3; 31., 1962 Meranti gisok 3 Basilan, PH Sulit _; 31., 1962 Meranti tembaga 10 Sabah, MAL Wong, 1973 Meranti merkuyung 12 Sabah, MAL Wong, 1973 Balau Putih 3 Perak, MAL Vincent, 1962 Seraya Melantai 13 Negeri Sembilan, Vincent, 1961 MAL Meranti merah 7 Basilan, PH Sulit 31 31., 1962 Lempung abang 4 Basilan, PH Sulit 33 31., 1962 Merkabang 7 Basilan, PH Sulit 31 31., 1962 100 m above sea level with varying aspects and slopes. A total of 23 balau putih trees were selected for annual measurement. Mean annual diameter growth over a period of 18 years was reported by Vincent (1962). The mean annual diameter growth for balau putih was 3 mm. It is a disap- pointingly 10w diameter growth for a species of meranti (Shorea). From Table 1 it can be seen that both Malaysia and the Philippines had similar ranges of growth rates. In both countries members of the genus Shorea show the highest variability in growth rate of all genera of dipterocarp. Mean annual diameter growth in logged over forests of East Kalimantan was reported by Setijono 33 31. (1979). Their report was based on 2 years of observation in eight study areas (79 one-hectare plots). In that report, species were grouped into exportable, locally commercial and other species. The results are summarized in Table 2. Mean annual diameter growth of exportable species ranged from 6 mm in Inne Dong Wha to 18 mm in Avedeco. The average for all concessions for exportable species was 10 mm. This figure is within the range of mean annual diameter growth of Malaysia and the Philippines' dipterocarp as shown in Table 1. Mean annual diameter growth in excess of 10 mm were in Avedeco, KRTP and Ratah Timber. This high growth rate may be due to more available space per tree, greater initial diameter, the presence of faster growing species, or Table 2. Mean annual diameter growth by group of species in eight concessions in East Kalimantan (from Setijono 33 31., 1979). Annual diameter growth of ..211.. “2:221:19 4353111“ .2221; spec1es mm mm mm mm Avedeco 15 18 ll 15 BFI 6 8 6 5 GPI 7 8 7 7 Inne Dong Wha 6 6 5 6 ITCI 7 8 8 8 KRTP ll 12 11 ll KTI 6 7 6 6 Ratah Timber 16 16 18 16 Average 9.2 10.4 8.7 9.1 10 better soils in those three concessions. When the first year's growth was compared with that for the second year, Setijono 31 _1. (1979) reported that in four out of five concessions first year diameter growth was greater than that for the second year. This may be due to greater competition from ground vegetation in the second year than in the first year. These same authors calculated the relationship between diameter and diameter growth rate in all eight concessions. The relation was significant statistically in four of the eight concessions. In doing this, they lumped data for all species, a practice which reduced the validity of the results. Diameter growth in unlogged dipterocarp forests at Pasoh, Malaysia was measured by Kato, Tadaki and Ogawa (1978). The growth data were based on trees over 10 cm diameter in a plot of 40 m x 200 m. Diameter was measured with tape at three different heights above ground, 1.23 m, 1.30 m, and 1.37 m. The three readings were averaged. Measurements were done over a period of 1.9 years. Maximum diameter growth recorded was 0.9 mm during the first year and 1.3 mm during 1.9 years. The growth was disappointingly slow. In East Kalimantan, ITCI established four permanent plots in unlogged forests, and eight permanent plots in logged over forests. Plots were established in 1972. Plot size ranged from 0.25 to 1.75 hectares. Trees over 15 cm 11 diameter were individually numbered and diameter measured yearly. Over a 6-year period, growth rates of trees in unlogged forests were compared with those of undamaged trees in logged over forests (Miller, 1980). The results were summarized in Table 3. Logging stimulated growth for the small diameter class. For medium diameter class, growth was stimulated when percent of trees cut was 20 percent. Growth rates in the most heavily cut areas was comparable with growth rates of exportable species in Avedeco, KRTP and Ratah Timber as reported by Setijono 31 31. (1979). The fact that logging stimulates growth may be due to more available growing space for trees remaining in the logged over forests. The results are open to question because Miller did not analyze separately for different species, grouping such diverse genera as Shorea and Anthoc33halus. The evidence that growth rate in logged over forests is greater than in unlogged forests is not surprising. The logging permits the remaining trees to have more growing space and develop larger crowns, and thus to grow faster. Growth related to crown position The effect of crown position on growth was studied by Murphy (1970). At E1 Verde, Luquillo forest in Puerto Rico, growth of trees in the lower canopy was compared with growth of trees in the upper canopy. It can be seen in Table 4 that basal area growth of upper canopy trees was at least 12 Table 3. Mean diameter growth of undamaged trees 6 years after 10 ging and of similar trees in unlogged forests Ifrom Miller, 1980). Mean diameter growth (mm/year) Diameter Unlogged Logged over forest with following class, mm forest percent of trees cut or damaged 4% 15% 20% 150 - 249 2 4 4 15 250 - 349 6 4 6 12 350 - 449 7 4 10 16 13 Table 4. Basal area increase by species as related to crown position (from Murphy, 1970) Basal area increase (cm?) per tree Species Lower canopy Upper canopy Dacryodes excelsa 6.8 23.2 Manilkara bidentata 4.6 17.5 Sloanea berteriana 1.7 20.9 Croton poecilanthus 3.7 9.6 14 three times greater than that for lower canopy trees. Further evidence on this point was reported by Crow and Weaver (1977). They studied 100 plots, each 0.08 hectare in size, located in Luquillo mountain of Puerto Rico. These plots were established 19 years ago. For a given species, trees were grouped into dominant, codominant, intermediate, and suppressed crown classes. Dominant trees grew fastest and suppressed trees the slowest. Problems in measurement Both very slow and fast growth of tropical rain forest trees were reported everywhere (Dawkins, 1959; Crow and Weaver, 1977; Sulit _1 _1., 1962). The great diversity of species and sites, and the lack of annual rings poses more problems than in temperate forests for developing suitable measurement techniques. It has been impossible to determine the rate of growth in tropical rain forest by stem analysis. The only method for determining the rate of growth of trees species is by laying out permanent plots in which the same trees are measured at intervals. The problem of how to select a suitable method which is simple, accurate and fast has challenged tropical research- ers. Dawkins (1956) suggested painting ten parallel rings on each tree and averaging the three closest readings. The method was found quite accurate in Sarawak and Sabah, but it was expensive (Nicholson, 1958). Furthermore Nicholson was doubtful whether Dawkins' method had any real advantage —--L I- 15 over the usual methods used in Sarawak and Sabah. For 52 weeks of 1955 and 1956, diameters of 10 trees each of Levoa brownii and Entandrophragma angolensis were measured weekly in Mpanga, Uganda (Dawkins, 1956). He cor- related diameter growth with rainfall. Growth was greater in the wet than in the dry season. THE STUDY AREAS Lgcation The study areas are located on three concessions in East Kalimantan forests. A concession is a tract of land leased by a company under a long term agreement. In this agreement the concessioner has cutting rights on a sustained yield basis. These concessions are: International Timber Corporation Indonesia (1101), Georgia Pacific Indonesia (GPI), and Kayan River Timber Products (KRTP). The ITCI concession is located in the southern part of East Kalimantan between the cities of Balikpapan and Samarin- da (Figure 1). It takes about one hour to reach by boat from Balikpapan. ITCI holds a forestry license on 601,750 hectares. The study site lies 60 km from ITCI's base camp and about 0.2 to 0.5 km from road 2321-A. The GPI concession is located in the center of East Kalimantan northwest of Samarinda (Figure 1). It takes about 45 minutes by GPI's plane from Samarinda. GPI holds a forestry license on 350,000 hectares. The study site lies 50 km from GPI's base camp about 0.2 to 0.8 km from the main road. The KRTP concession is located in the northern part of East Kalimantan, west of Tarakan, a northern city of East 16 17 Figure 1. The location of I.T.C.I., G.P.I. and K.R.T.P. concessions in East Kalimantan. ?. Q, 9 CELEBES P. \e S E A or“ 0 S a b a h 0‘6 O I- 9 ’_;’~-’-‘ °\ _ I, ‘. . < q. ,’ Tarakan O: 0‘ I, K.R.T. ' 1’. I- \§ ) ( 04‘ ’l (D .4 _ 5 a ,’ 9° ' t - O: k , ’1 East Ka .ma an q \ ("T- ’ “I, \\ 1- a”: («“133 6.1.: l. m \I” - :3 < W e s t I." '“"""‘-.. I Kalimantan :. L. _ -marlndaz on. .90..” a. ' .C. . (a we", Central .°"-. Ba” ape" N .0 '. “‘7‘? :1". Ka I imantan ‘5' A A $/ ’1‘. 3...; $7 a :‘o. ..‘.. EC... 7 .--' 3' "' /A A { SOUth UAwA SEA Scale of km T Q o zoo 400 19 Kalimantan (Figure 1). It takes about six hours by boat from Tarakan. KRTP holds a forestry license on 325,000 hec- tares. The study site lies 9 km from KRTP's base camp, about 0.2 to 0.5 km from road M. 21m East Kalimantan climate is uniform throughout the year. The temperature varies only minimally, from 25.90C in the coldest month of February to 27.400 in the warmest month of September (Central Bureau of Statistics, 1976). Rainfall data are summarized in Table 5. The annual rainfall varies from 2,000 to 2,800 mm and is distributed throughout the year. Therefore, the soils just under the surface practically always remain continuously moist. This rainfall is important as a source nutrient input into the ecosystem (Jordan 31 31., 1980). Even though July is the month with the least rainfall, it is still wet, with 118 to 191 mm rainfall for the month. However, in ITCI and GPI three weeks without rain were recorded in 1980. Those three weeks may be the only period of water stress during the year. Both temperature and rainfall in the three study areas provide favorable conditions for plant growth. Tapography East Kalimantan is level and near sea level in the east. In the middle it is generally undulating or hilly, about 40% 20 Table 5. Amount and distribution of rainfall in the three study areas (Directorate of Forest Inventory and Planning, 1968, and ITCI unpublished data) Month with Month with Study Annual least ra1n most ra1n areas Rainfall Days of Month Amount Month Amount Rain of rain of rain mm mm mm ITCI 2123 177 July 118 Dec. 236 GPI 2580 121 July 144 Dec. 321 KRTP 2768 162 July 191 Dec. 261 21 of the land having elevations 500 to 1000 m above sea level. The mountainous mass is located on the border of Sarawak, Sabah and Central Kalimantan. This mountain range is less than 2,000 m in elevation. Mt. Kinabalu, 4,500 m above sea level, is located in Sabah. The ITCI concession is located at elevations of 0-100 m above sea level. The topography is generally undulating with some parts hilly with slopes over 60%. The study site is undulating. In some parts of plots 5, 6 and 8, the slope is more than 75%. GPI concession has altitudes varying from 100 to 645 m above sea level. The topography generally is undulating in the west part. The swampy area is found in the southern part between Long Nah and Muara Mawai villages. KRTP concession is located at altitudes varying from 100 to 1,500 m above sea level. Its topography varies from undulating to mountainous (Directorate of Forest Inventory and Planning, 1968). £211.: , The references used to estimate the most common soil orders in the three study areas were from Directorate of Forest Inventory and Planning, 1968 and ITCI's soil map. These references use old terminology. Their equivalents in new terminology and interpretation were obtained by using Buol, Hole and McCraken, 1973; Soil Survey Staff, 1975 and Foth and Schafer, 1980. 22 The most extensive soils in the three study areas are Red and Yellow Podsolic Soils. These soils are presently recognized as Ultisols. Ultisols are soils that are the most weathered and show the ultimate effects of leaching. Ultisols are characterized by mineral soils that have B—2 horizon, 20 percent more clay than the upper on B-l. Ulti- sols have low base saturation, the base saturation decreases with increasing soil depth. Normally most of the bases are held in the vegetation and the upper few centimeters of soil. The higher base saturation in the upper soil layers reflects the direct cycling of bases by vegetation. When the climax forest is cut and burned, nutrients stored for thousands of years in the vegetation are suddenly made soluble. Large amounts are lost to leaching and washing, causing a sudden decline of the nutrient level of the entire system. This is shown in slash and burn agriculture as practiced by native East Kalimantan cultivators. The next most common soils in the three study areas are Reddish Brown Lateritic, Yellowish Brown Lateritic and Latosols. These soils are presently recognized as Oxisols. They have very stable soil structure consisting of fine and stable aggregates. The water availability to plants is very low. Unless there is frequent rain the soils are droughty. Oxisols are characterized by the presence of an oxid upper horizon, at least 30 centimeters thick. They have subsurface horizons which are intensively weathered. 23 The subsurface horizons consist of very insoluble minerals such as quartz and hydrated oxides or iron and aluminum. Vegetation In the three study areas the vegetation is called tr0pi- cal rain forest. The vegetation is dominated by the family Dipterocarpaceae. The tallest and most abundant species of Dipterocarpaceae in the three study areas are meranti merembung, meranti merkuyung and meranti tembaga, all called red meranti. They reach far above other trees, attaining heights of 60, 75 and 70 m respectively. All have large buttresses, 4, 2 and l m tall respectively. They may occur singly or in a group. Among the tallest and most abundant species of Diptero- carpaceae in one study area, but least abundant in other study areas are kapur tanduk, damar siput, urat mata and meranti kalunti. Kapur tanduk is abundant in ITCI, where it grows 80 m tall. Damar siput, a yellow meranti, is abundant in GPI, reaching heights of 60 m. The buttresses are usually short. The name is derived from the damar exudate of yellow to dark brown crust, and siput the word for snail. So damar siput means snail-shaped exudation. Urat mata and meranti kalunti are found only in KRTP. Urat mata is a large tree up to 65 m high. The buttresses are large, up to 5 m high. Meranti kalunti is a large tree reaching a height of 60 m. 24 The second tall canopy is called second layer. Members of the second layer which are most abundant are Dipterocar- paceae, Sepotaceae and Lauraceae. Among Sapotaceae is nato, a group of species of the genus Palaq3jum. The trees have white latex in the bark and often also in the leaves, flowers and fruits. Nato may grow 50 m tall and most have columnar boles and buttresses. Among the Lauraceae are Medang and Ulin. Medang is abundant only in ITCI, while Ulin is abun- dant only in ITCI and GP. Medang includes many tree species, all characterized by aromatic substances smelling of resin, cinnamon and citronella. Medang may reach 40 m height. Ulin (Eusideroxylon zwageri) is known as ironwood because the wood is very strong and heavy. It is resistant to sea water. Ulin grown 50 m tall. Trees with crowns below the second layer are called the third layer. The most abundant species was kayu darah. Darah means blood, from a blood-like exudate. It is a small to medium tree up to 30 m, often with stilt roots. The average numbers of trees per hectare in unlogged forests of the three concessions is summarized in Table 6. That table is based on the areas logged in a 1-year period (1975-1976) in each concession. In Table 6 are given the numbers of trees per hectare in various diameter classes in the three concessions. The upper most three lines are based on a sampling of 0.75% of the area cut in one year, 1975-1976. The bottom six lines are based on the 29 plots 25 Table 6. Average number of trees per hectare by diameter class in the three concessions (from Soekotjo 33 31., 1976 and Setijono 33 31., 1978). Diameter in cm Location 10 to 20 20 to 35 35 to 50 50+ Area logged in 1975-1976, before logging ITCI 145 21 33 32 GPI 110 89 46 38 KRTP 109 63 26 26 My study area, before logging ITCI -- 42 18 17 GPI -- l4 9 l7 KRTP -- 29 11 18 My study area, after logging ITCI 146 18 8 7 GPI 183 9 4 7 KRTP 152 16 4 7 26 which I studied. In all cases the number of trees 10-20 cm in diameter was greater than the number of trees in the 20-35 or 35-50 cm diameter class. The logging itself removed trees 50 cm and over in diameter, the only 50 cm trees left standing belonging to unmerchantable species. As the bottom six lines show, the logging caused considerable mortality in the trees less than 50 cm in diameter. Logging operations Logging operations have been conducted since 1967. The amounts cut are summarized in Table 7. To meet the annual harvest target, hundreds of km of rocked main line roads have been established in all three concessions. This road facili- tates year-round logging operations. The annual area cut is divided into blocks as logging units. Each logging unit covers an area of approximately one hundred square kilometers. Felling and bucking are done by chain saw. Skidding is done by caterpillar tractors. Logs are loaded onto logging trucks and transported to a log pond. 27 Table 7. Average cut per hectare by group of species and total cut in last 10 years operation in the three concessions (from ITCI, GPI, and KRTP's working plan 1980-1981). , Total cut in Average cut by group of spec1es 10 years Study 1970 1979 areas Meranti Keruing Other Total Area Volume Kapur Agathis m3 per ha. 1,000ha Milgimi m ITCI 54.0 6.7 1.9 - 3.4 65.6 167.2 9.2 GPI 48.7 4.8 1.3 - 0.4 55.2 41.7 2.3 KRTP 49.6 3.6 20.3 8.1 6.2 87.8 49.5 2.7 METHODS Plot establishment and measurement In February 1977, 29 one-hectare permanent growth study plots were established in three concessions. The number and distance of plots from base camp and main road by con- cessions are given in Table 8. The location of each plot is shown in Figure 2, 3 and 4. Plot boundaries and trees along paths to the plots were carefully painted red to ensure that the plots could be found for subsequent measurement. All trees 10 cm diameter and up were numbered with aluminum tags nailed to the tree above the point of measurement (1.30 m). At the point of measurement a ring was painted at 1.3 m height. For a buttressed tree, the point 0f measurement was located 2 m above the buttress. Trees were identified and their diame- ters measured with diameter tape to the nearest mm. Before logging in 1977, the following data were recorded for each tree: number, species (full common name written out) and diameter in mm. These data were recorded on tally sheets. Immediately after logging, the plots were revisited, and the percentage of crown (to the nearest 25%) damaged on each tree was recorded on the same tally sheets. When the plots were remeasured in 1978 and 1979, new tally sheets 28 29 Table 8. Number and location of plots on the three con- cessions Concessions N0. of Distance from Road Distance from plots base camp name road km km ITCI 9 60 2321-A 0.2 to 0.5 GPI 10 50 1000 0.1 to 0.8 KRTP IO 9 Road-M 0.2 to 0.5 30 Figure 2. The distribution of permanent growth plots in I.T.C.I. concession. 31 32 Figure 3. The distribution of permanent growth plots in G.P.I. concession. 33 O °d 1357 Road 1370 read main (3.P.L Scale of km 34 Figure 4. The distribution of permanent growth plots in K.R.T.P. concession. 35 NAIII K.R.T P. Scale of km 0 .4 o0 36 were used (containing no data from the 1977 measurements) and diameters were recorded for each tree. When the plots were remeasured in 1980 tally sheets were prepared before- hand. Those tally sheets included number, species and 1977 diameter, but not the logging damage nor the 1978 or 1979 diameters. The 1980 diameters were recorded on these already prepared data sheets. Measurements were done by a crew consisting of one leader and six members for ten plots in each company. This crew spent 45 days for plot establishment. In June 1980, I and four crew members returned. We mapped all trees, using a grid system in which each plot was divided into 25 subplots, each 20 m x 20 m. Using a scale 1 m in the field equal to 1 mm on paper, the tree's locations were charted on cross section paper. We also measured dis— tance of each tree to the nearest opening caused by logging diameter, and basal area of the trees nearest neighbors. To obtain this measure of competition around each tree, I used the "Panama Basal Area Angle Gauge", an instrument designed for plotless timber cruising. I used the subject tree as a center of measurement. By looking in every direction through the instrument, and counting the number of trees whose d.b.h. appear larger than the crosspiece or aperture the basal area of its competitors was determined. In 1978 and 1979, when the tally sheets did not contain data from the previous measurement, there was no opportunity 37 to check on possible mistakes in measurement or recording. In 1980 there was such an opportunity, but there was actually no such check as the recorder did not ask for re-measurement of trees which had a smaller diameter in 1980 than in 1977. Actually about 2% of the trees had smaller recorded diameters in 1980 than in 1977, presumably due to a mistake in recording at one time or the other. These trees were eliminated from all further analyses. Presumably mistakes in the opposite direction were made on an equal number of trees, but such mistakes were not detectable. Data handling Data from the tally sheets were punched using an IBM 026 keypunch. I used a card coded to the specifications as shown in Table 9. This instruction card can be set up to allow the IBM 026 keypunch to duplicate automatically or skip unused columns of the data cards. After all cards were punched, proofreading was needed to correct punching errors in the cards. This proofreading was accomplished by using lister/printer. Lister/printer output printed data for each plot by companies in the same format as in the original tally sheets. The possibility to correct errors and enter new data is easier in this way. To rearrange the contents of a file into the order that meets the specification may be done through the use of a sorting machine. After we determine which columns in the 38 Table 9. Instruction card using keypunch drum Character in the Columns first and following Data entry columns field l - 6 -+++++ skip. 7 - 8 /A company - letter code. 9 - 10 -+ skip. 11 — 12 space + plot number - numeric code 13 - 14 -+ skip. 15 - 16 space + sub-plot number-numeric code. 17 - 18 -+ skip. l9 - 21 space ++ tree number - numeric code. 22 - 23 -+ skip. 24 - 26 /AA species - letter code. 27 - 29 -++ skip 30 - 31 space + distance - numeric code. 32 - 34 -++ skip. 35 - 37 space ++ diameter 1977 - numeric code. 38 - 52 —++++++++++++++ skip. 53 - 55 space ++ diameter 1980 - numeric code. 56 - 57 -+ skip. 58 — 59 space + basal area - numeric code. 60 - 62 -++ skip. 63 - 64 space + diameter growth - numeric code. 39 field have to be sorted, sorting is performed in descending order from high to low field. Finally the data were stored in a magnetic tape called a "stranger" tape. I did this so that I could return to Indonesia with all the data in a convenient form. Computations The previously punched IBM cards were sorted by species, so that regression equations could be calculated for each species. All computations were performed using Texas Instru- ments TI Programmable 58 C calculator, using a library module. The procedures are summarized in Table 10. Once the library module was inserted in the calculator, the next step was to initialize the calculator for statistics by pressing 2nd Pgm 1 SBR CLR. Data entry has to be in pair of values (X1, Y1). A faulty entry can be removed by reen- tering the unwanted pair of value and pressing INV 2nd 2 +. To determine whether two regression lines have a common slope I used Student's "t" test as described by Steel and Torrie (1980). The procedure is relatively easy, and is shown below. To calculate "t", I used the following equation derived from that given by Steel and Torrie (p. 258). b1'b2 VE§(1/ssx1 + 1/ssx2) fl 1 where b] slope of regression l 4O Table 10. Procedures used to calculate growth as related to initial diameter using T1 Programmable 58 C Step Data entry Press 1. Initialize 2nd Pgm l SBR CLR 2. Enter data point (X1, Y1) X-array Xi Xi xzt Y-array Y1 Y1 2nd 2 + 3. To remove unwanted data point Yj Yj INV 2nd 2 + 4. Computation: Y-intercept 2nd 0p 12 Slope xzt Mean Y-array 2nd x Mean X—array xzt Variance Y N weighting 2nd 0p 11 Variance X N weighting xit Correlation Coefficient 2nd 0p 13 Compute estimate Y' on Xk Xk Xk 2nd 0p 14 SSXI SSX2 where SSYl SSY2 SCPl SCP2 "1 "2 41 slope of regression 2 sum of z (X1j sum of z (ij pooled squares X of regression 1 -71.)? squares X of regression 2 - 72.)? residual sums of squares for two separate regressions divided by degree of freedom (SSYl - sum of z (Y1j sum of z (Yzj sum of 2 (X1j sum of 2 (ij number number (csp112/ssx1 + ssvz - (scp2)2/ssx2) n1+n2-4 squares Y of regression l = V102 squares Y of regression 2 - 172.)? cross-products of regression 1 - 7].)(Y1j - 7].) cross-products of regression 2 - 72.)(Y2j - Y2.) of observations of regression l of observations of regression 2 Computation procedures to calculate "t" are summarized in Table 11. From Table 11 2 it can be seen that sp is equal to (line 1 + line 2 in column 10) divided by (line 1 + line 2 in column 2 minus 4), while (1/SSX1 + 1/SSX2) is equal to line 1 + line 2 in column 7. Therefore, using this table t is easy to solve. 42 V Subtract line 1 - line 2. Table 11. Procedures used to calculate student's "t" for testing difference between two b's, using T1 - 58 C calculator 1_/ Column 1 3 4 5 6 7 8 9 10 Press (Key Sequence) 2nd x:t 2nd x:t 1 2nd c01.4. c01.5 op op 11 divided op squa minus 12 times times col. 6 13 res col.6 col. col. times 2 2 col. 6 Elements of computation 2 spp a b ssv ssx 1/ssx R scpz/ (55;- ssx scp )/ SSX X X V 1/ x Sum line 1 + line 2. 43 Procedures for calculating the effect of basal area of tree competitor on growth are as follows: Step 1. Set up table for the analysis (Table 12) where SS between-class = (020)2 (D30)2 n20 + n30 (Dgo)z (0)2 n90 n SS within-class SS total - SS between-class SS total 53 residual of regression. Procedures for calculating the effect of distance to the opening to subject tree on growth are the same as those for calculating the effect of basal area of tree competitor on growth. 44 Table 12. Procedures used to calculate the effect of basal area of tree's competitors on diameter growth of subject tree, using TI.58 C calculator actual Y - Y' basal n initial dia. (X1, dia. calculated area EX ZX/n growth ZY Y' = D Y 20 3O 90 '36 20 Step 2, Calculate XY by addition and Y' from Y' = a + b (EX/n). ZY' = nY' Step 3, Set up table for the analysis of variance RESULTS AND DISCUSSION Mean annual diameter3growth I present mean annual diameter growth data of the most common species in Table 13. My analysis was based on locally recognized species, some of which may contain several species as recognized by taxonomists. Mean annual diameter growth ranged from 4 to 11 mm. It was greatest for dipterocarps belonging to the overstory or first layer, and least for non-dipterocarps belonging to the second layer. The ranges of mean annual diameter growth were similar to those reported in other countries (Tables 1 and 14). Growth related to initial diameter 0f greater value than mean annual diameter growth is the relationship between initial diameter and diameter growth. For a given species I considered diameter growth as the dependent variable and initial diameter as the inde- pendent variable. Then I calculated the correlation between these two variables. The results are shown in column 4, 5 and 6 of Table 14, and are based on data from 40 to 388 trees per species. In all species there was a strong and statistically significant correlation between diameter and diameter growth, the greater the diameter, the 45 46 Table 13. Mean annual diameter growth by species as related to initial diameter Growth (Y) as a function 2:2" $§§2 of initial diameter (x) S . . . pec1es d' . 1am. diam. 2 Slope Y growth r flfiflflifl inter- diam. cept mm mm mm/mm mm Dipterocarps 330rea Red meranti 10.0 298 .56 .018 4.5 White meranti 8.6 253 .45 .019 3.7 Yellow meranti 9.6 331 .61 .018 3.4 Bangkirai 8.8 298 .62 .017 3.6 Dryobalanop3 Kapur 10.0 303 .74 .020 3.9 Parashorea Bagtikan 9.0 274 .76 .026 2.2 Dipterocarpus Keruing 9.0 254 .76 .024 2.7 Cotylelobium Resak 7.5 199 .64 .029 1.6 Hopea Nyerakat 9.0 288 .85 .021 3.0 Non Dipterocarps Commercial Ulin 11.0 348 .80 .021 3.6 Nato 7.5 214 .71 .024 2.2 Medang 7.0 207 .83 .024 1. Non commercial Langsat 6.3 245 .63 .030 1.3 Lalan 6.0 219 .89 .030 -l.0 Temberas 5.7 196 .78 .029 0.2 Kayu arang 6.0 208 .86 .028 0.0 Jambu 6.1 204 .85 .026 0.8 Marjelawat 4.5 148 .77 .025 2.7 Banitan 5.3 168 .72 .024 1.3 47 Table 13. (continued) Growth (Y) as a function "ea" 3:32 of initial diameter (x) Species ann. diam. diam. 2 Slope y 9F0Wth r growth inter- diam. cept Mendarahan 4.9 183 .74 .024 0 6 Margelang 4.5 148 .77 .023 1.0 Api 4.6 175 .79 .021 0.9 Kempas 7.7 292 .59 .020 1.9 Margaram 4.5 178 .63 .017 l 0 Marakeladi 4.4 182 .53 .017 l l 48 Table 14. Mean annual diameter growth data by species, in tropical rain forests of Zimbabwe, Guyana and Puerto Rico Mean annual . Species diameter LocatTOH AUthor growth mm Baikiaeae plurijuga 5 Zimbabwe Osmaston (1956). 0c0tea rodiaei 5 Guyana Prince (1973). Fast growing species: Puerto Rico Crow and Weaver (1977). Buchenavia capitata 7 " ” Guarea trichilioides 8 " " Slowggrowing species: " " Tabebuia heterophylla 2.8 " n Dacryodes excelsa 2,5 n n Didymopanax morototoni 3,] u u 49 more rapid the growth. Column 4 is r2. It is called the coefficient of deter- mination and is a measure of the variation due to differences in initial diameter. In my results ranged from 0.45 to 0.89, showing that 45-89% of the variation in diameter growth was associated with variation in initial diameter. Column 5 is the slope. Slope tells us the relationship of growth to change in initial diameter. An example, for yellow meranti the slope is 0.018. Thus, for 1 mm increase in initial diameter, diameter growth will increase 0.018 mm. Column 6 is the Y—intercept, a measure of inherent growth rate. The Y-intercepts ranged from -1.0 to 4.5. Red meranti and kapur had highest Y-intercept. This is interesting because some members of red meranti and kapur are capable to be the tallest canopy in tropical rain forest. Most merantis have high Y-intercepts. 0n the contrary, third layer species have low Y-intercepts. Comparisons of diameter growth among species The previous discussion on growth related to initial diameter pointed out that slope may serve as a measure of rate of change of diameter growth. This rate of change supplies for a tool of comparing growth rate among species. For that reason, comparisons of growth rates among species have to use slope. It is possible to test the homogeneity of slopes by using Student's “t" test. 50 Table 15 summerizes results of student's "t" for dipterocarp species. Yellow meranti, White meranti, Red meranti and Bangkirai belong to the genus Shorea. The values of "t" among these species are small, showing that they do not differ statistically. That is, they have a common lepe, as shown in Figure 5. They do not differ in rate of change in diameter growth but do differ in inherent growth rate. Red meranti shows the highest inherent growth rate among genus Shorea, while yellow meranti the lowest. The slopes of the merantis (Shorea) and of keruing (Dipterocarpus) differ statistically. Figure 6 shows that the regression line of keruing crosses the regression lines of yellow meranti and bangkirai at initial diameter of 131 and 150 mm respectively. Growth related to competition Each individual tree in a forest has a definite amount of growing space. As a tree grows, it must compete with its neighbors. The degree of competition is determined by the ability of a tree to utilize limited resources. Numerous calculation methods for competition have been pr0posed and tested under a variety of conditions. In this dissertation I regarded the distance to competitors and size of competi- tors as most important. The greater the distance or the smaller the competitors, the more the available growing space. As a matter of convenience, I used basal area of each 51 .3, Pass, wee ea .em _esep wee ea eeeebweeemvmee abeabwewea_ma \a -- umxmgmxz «mm.m -- xmmmm on. amm.m -- gsamg em._ mm.P «me.m -- acmzswg FN.P mm. rpm.m we. -- cmxwpmmm km._ .ee.~ ao._ s.em.m .mm.~ --- waewxmeem mm.~ arum.~ mu. ramm.m «apm.m we. -- _ucmgwe com me. rmo.~ mp. mF.N AN.F ex. em. -- wucmsme ayes: em. amo.m mm. *a—o.m mm._ mm. om. mm. - Pucmgoe soppm> pmxmsmzz xmmmm szqu mcwasmx :mxmpmmm Pmsmxmcmm Tummums wwnmume %WHMmME mmmumagmoosmpavo 4o mmwomam gem m.n Low ea: m.ucmu=um we xwgumz .mP w—EMP 52 Figure 5. The four parallel regression lines of red meranti, white meranti, bangkirai and yellow meranti. 53 growth Diameter emnm lnital diameter isomni 54 Figure 6. The regression line of keruing crosses regression line of yellow meranti and bangkirai. 55 Diameter growth 7mm 5mm- Inial diameter 150 mm 56 tree's neighbors as a measure of competition, measuring basal area with a Panama Basal Area Angle Gauge. The effect of competition on diameter growth is sum- marized in Table 16. In computing this table, I grouped all species. The greater the basal area of competitors and the more intense the competition, the less the diameter growth. An analysis of variance showed that the differences were statistically significant (0.1% level). Growth related to distance from the opening Soekotjo and Dickmann (1978) reported that opening of the canopy by logging increased survival and growth of seedlings of exportable species. Partial shade was bene- ficial for small seedlings, but seedlings taller than 1 m grew most rapidly in full sunlight. The present study was designed to test diameter growth response of larger trees of dipterocarp species under dif- ferent degrees of crown release. I measured the distance from sample trees to the openings caused by logging. I analyzed the data in terms of deviations from the average growth rate expected for a given species and diameter (as shown in Table 13). The results are summarized in Table 17. The closer the subject trees to the openings the more that actual diameter growth exceeded predicted diameter growth. 57 Table 16. The effect of competition on diameter growth Amount actual growth Basal area Number exceeded (or was less of of than) average growth competitors trees for trees of the same diameter m2 per ha. mm 4.6 6 11.0 6.9 5 8.0 9.2 44 4.4 11.5 103 2.1 13.8 192 .7 16.1 332 .6 18.4 865 — .4 20.7 286 -1.8 58 Table 17. Diameter growth of dipterocarps at varying distances from openings caused by loggings Distance Number Amount actual growth to of exceeded (or was less openings trees than) average growth for trees of the same diameter m mm 2 7 3.8 3 34 1.3 4 65 .4 5 158 .1 6 176 - .1 7 401 — .1 8 77 — .8 59 The application of growth data In the previous discussions, I tried to show growth behavior of residual stands in logged over forests of East Kalimantan. Every year concession holders have to allocate the annual cut in such a way so that no abrupt reduction in the next series of cut. Logging is done in virgin forests. Mature and overmature trees of exportable species, diameter above 50 cm are cut. Residual stands have to function as the source of later cuts. Consequently, it is of interest to calculate period of change from one diameter to the next diameter class. I summarized diameter changes for trees of three dif- ferent initial diameters in Table 18. The calculations used in preparing Table 18 were as follows, using data from Table 13. a. A red meranti tree growing from 200 to 300 mm grows at an average rate equal to that of a 250-mm tree, which Y intercept + (rate of increase) diameter 4.5 + (.018)(250) = 9.02 mm/year b. For red meranti, the number of years needed to grow 100 mm from 200 to 300 mm _ 100 mm = ' 9.02 mm/year 1‘ years Using the above method, I calculated the times necessary for trees to grow from 200 to 300 mm, from 300 to 400 mm, 60 Table 18. Years needed for trees of given present diameters to attain future diameters of 350, 450 and 550 mm. Mean Years needed to attain Group of Initial annual diameter 0f species diameter diameter 300 mm 400 mm 500 mm growth mm mm --------- years ---------- Red meranti 200 9.0 11 20 28 300 10.8 9 17 400 12.6 8 White meranti 200 8.5 12 22 31 300 10.3 10 19 400 11.2 9 Yellow meranti 200 7.9 13 23 32 300 9.7 10 19 400 11.5 9 Bangkirai 200 7.8 13 24 34 300 9.5 11 20 400 11.7 9 Kapur 200 8.9 11 20 28 300 10.9 ’ 9 17 400 12.9 8 Bagtikan 200 8.7 12 21 28 300 11.3 9 16 400 13.9 7 Keruing 200 8.7 12 21 28 300 11.1 9 16 400 13.5 7 Resak 200 8.8 11 20 27 300 11.7 9 16 400 14.5 7 Nyerakat 200 8.2 12 22 30 300 10.3 10 18 400 12.4 8 Ulin 200 8.8 11 20 28 300 10.9 9 17 400 13.0 8 Nato 200 8.2 12 21 31 300 10.6 9 18 400 13.0 8 Table 18 (continued) 61 Mean Years needed to attain Group of Initial annual diameter of species diameter diameter growth 300 mm 400 mm 500 mm mm mm -------- years --------- Medang 200 7.7 13 23 31 300 10.1 10 18 400 12.5 8 Langsat 200 8.8 11 29 --1/ 300 11.7 - -- Lalan 200 6.5 15 25 ~- 300 9.5 10 -- Temberas 200 7.2 14 24 -- 300 10.1 10 -- Kayu arang 200 6.9 15 25 -- 300 9.7 10 -- Jambu 200 7.3 14 24 -- 300 9.9 10 -- Marjelawat 200 6.8 15 26 -- 300 9.2 11 -- Banitan 200 7.3 14 24 -- 300 9.7 10 -- Mendarahan 200 6.6 15 26 -- 300 8.9 11 -- Margelang 200 6.8 15 26 -- 300 9.2 11 -- Api 200 6.3 16 28 -- 300 8.5 12 -- Kempas 200 7.0 14 25 34 300 9.0 11 20 400 10.9 9 Margaram 200 6.2 16 28 -- 300 8.6 12 -- Marakeladi 200 5.4 19 33 -- 300 7.0 14 -- 1/ Langsat and the other eleven species at the bottom of the table are normally small trees which do not reach diameter of 500 mm. 62 and from 400 to 500 mm for each species. Then, assuming a constant growth rate for each growth period, I calculated the growth after periods of 15, 25 and 35 years. This method, although approximate, is probably accurate enough in view of the many uncertainties regarding competition. In this way I prepared Table 19. Estimating the amount cut in the next cuttiggfgycle The evaluation is based on the amount cut per hectare. In the last logging, ITCI, GPI and KRTP cut on the average of 10, 9 and 11 trees per hectare respectively. In ITCI and GPI, species cut consist of red meranti, yellow meranti, white meranti and kapur, white KRTP red meranti, white meranti (kalunti), bagtikan and keruing. On p. 59 I described the methods used to forecast future diameters of 20, 30 and 40 cm. Using the same methods, but working backwards, I calculated the present diameter of a tree which is expected to be exactly 50 cm in diameter 35 years hence. Then I counted the numbers of trees of that diameter or greater which will reach merchantable size (50 cm) in 35 years. The results are presented in Table 20, which includes only those species which are commercially valuable at the present time. According to this table, the cut 35 years hence can be almost the same as the cut during the initial 63 Table 19. Future diameter growth by species and diameter on permanent plots of logged over forests in the three concessions of East Kalimantan tropical rain forests Mean Diameter (mm) reached Species Initial annual after diameter diameter growth 15 yrs 25 yrs 35 yrs mm mm ----------- mm ----------- Red meranti 250 9.0 403 530 676 350 10.8 532 682 450 12.6 660 White meranti 250 8.5 394 512 647 350 10.3 520 658 450 11.2 613 Yellow meranti 250 7.9 383 496 627 350 9.7 514 450 11.5 643 Bangkirai 250 7.8 381 482 622 350 9.5 535 450 11.7 667 Kapur 250 8.9 401 531 672 350 10.9 535 450 12.9 667 Bagtikan 250 8.7 399 537 695 350 11.3 546 720 450 13.9 688 Keruing 250 8.7 398 532 694 350 11.1 541 709 450 13.5 680 Resak 250 8.8 402 546 724 350 11.7 554 740 450 14.5 701 Nyerakat 250 8.2 389 510 651 350 10.3 520 676 450 12.4 660 Ulin 250 8.8 399 682 350 10.9 535 694 450 13.0 670 64 Table 19. (continued) Mean Diameter (mm) reached Species Initial annual after diameter diameter growth 151yrs 25 yrs 35 yrs mm mm Nato 250 8.2 389 506 669 350 10.6 573 594 450 13.0 672 Medang 250 7.7 380 498 642 350 10.1 524 678 450 12.5 664 Langsat 250 8.8 403 521 __a 350 11.7 555 -- Lelan 250 5,5 353 466 __a 350 9.5 516 -- Temberas 250 7.3 373 -_a 350 10.1 525 '- Kayu arang 250 6.9 365 474 --a 350 9.7 -- Jambu 250 7.3 372 487 --a 350 9.9 521 " Marjelawat 250 6.8 364 468 --a 350 9.2 506 '- Banitan 250 7,3 372 484 --a 350 9.7 516 -- Mendarahan 250 6.6 358 __a 350 8.9 493 '- Margelang 250 6.8 373 467 __a 350 9.2 506 '- Api 250 6.3 355 451 --a 350 8.5 495 -- Kempas 250 7.0 366 468 586 350 9.0 456 632 450 10.9 635 Margaram 250 6.2 354 448 --a 350 8.6 498 -- 65 Table 19. (continued) Mean Diameter (mm) reached Species Initial annual after diameter diameter growth 15 yrs 25 yrs 35 yrs mm mm ----------- mm ............ Marakeladi 250 5.4 341 407 --a 350 7.0 466 -- 2Normally a small tree not reaching a diameter of 50 cm. 66 Table 20. Previous cuts and predicted future cuts after 35 years growth Trees reaching harvestable . . size for the next 35 ears Spec1es and Prev1ous cut cut y concession range average --trees per ha-- ----- trees per ha ------ ITCI concession: Red meranti 2 to 13 5 Yellow meranti 0 to 5 2 White meranti 0 to 3 1 Kapur 1 to 9 3 Total 10 ll GPI concession: Red meranti l to 11 6 Yellow meranti 0 to 4 2 White meranti 0 to 3 1 Kapur 0 to 3 1 Total 9 10 KRTP concession: Red meranti 2 to 11 3 White meranti l to 6 2 Bagtikan 0 to 5 l Keruing 0 to 12 3 Total 11 9 67 logging. If we consider the fact that many species not logged at the present time may become merchantable in the future, the harvests 35 years hence may be even greater than those at the present time. Limitations of previous growth studies As was explained previously, there is a strong relation- ship between diameter and growth rate in all species. Unfortunately, this relationship has been ignored by many previous researchers in tropical forests. Several have chosen to present data on mean annual growth only. Such data are so dependent on diameter as to be of almost no value when comparing species or sites. In 1956 Osmaston published a method of estimating age- diameter relationships in tropical trees without growth rings. The essential features of his method were as follows: a. Establish permanent plots and measure diameter growth over an interval of several years. b. Plot the growth rate over diameter and draw a smooth curve showing the relation between these two variables. c. Using growth rates derived from the smooth curve, compute the number of years required to grow from 10 to 20 cm, 20 to 30 cm, etc. d. Add these years together to obtain the estimated age of a mature tree of any given size, say 100 cm. 68 e. Divide the diameter of the mature tree by the esti- mated age to obtain the mean annual diameter growth during the life of that tree. Osmaston's method appears valid and was probably the best available in 1956 when calculators were less sophisticated than in 1981. The plotting of many hundreds of data points was much more laborious than the calculation of regression equations on the TI-58 C calculator. Osmaston could have derived regression equations for the diameter-growth rate relationships from his smooth curves but did not. Such regression equations would probably not have been quite as accurate as my calculated ones, but would have been adequate for many purposes. Sulit 33 31. (1962) also plotted data from Phillipine plots for growth in diameter against diameter, and drew smooth curves. They presented curves for two dipterocarp species, nato and karuing measured for 4, 22 and 37 years since logging. Their curves followed nearly straight lines for the diameter range 10-60 cm; at larger and smaller diameters the rate of diameter increase per unit of diameter decreased. Although they presented no regression equations, such equations can be estimated from their curves as follows, where Y, a, b, and x are mean annual diameter growth, Y- intercept, rate of increase in diameter growth and diameter, respectively, all measurements being in mm. Their regression equations are as follows: 69 Y = a + b X Y = 5.2 + .005 X for area logged 4 years previously Y = 0.0 + .02 X for areas logged 28 and 31 years respec- tively He also presented such a curve (only slightly curvilinear) for all dipterocarps in virgin forest, the approximate equa- tion being Y = 0.8 + .005 X The above data from Sulit 33 31. appear satisfactory except for the fact that they lumped data for two-several species, thus reducing the value of the data when forecas- ting. In another part of their paper, they reported average mean annual growth rates for 10 species. Those data are of limited value because they depend so heavily on the (unstated) diameters of the trees sampled. Later, Wong (1973) attempted to use Osmaston's method to study growth in Sabah, Malaysia. Unfortunately his tables are so complex and poorly labelled, and the results of some of his calculations so puzzling to interpret that it is difficult to state the value of the study. SUMMARY AND CONCLUSIONS Tropical rain forest of East Kalimantan covers about 172,000 km2 or about 85 percent of the total land area. It is the most important forest of Indonesia. Roughly 50 per- cent of Indonesian log exports are from this area. Every year concession holders have to allocate the annual cut in such a way so that no abrupt reduction for the next series of cut. Logging is done in virgin forests. Mature and over- mature trees of exportable species above 50 cm in diameter are cut. The amount cut ranged from 3 to 22 trees per hec- tare. About 11 to 26 trees of exportable and locally com- mercial species are left per hectare. These trees consist of diameter between 200 mm and 500 mm. They have to function as the connecting link for the subsequent cut. It has been a problem to determine the rate of growth in the tropical rain forests. Tropical rain forest trees do not produce annual rings. Whenever growth rings seem to be present, they are not clearly distinguishable. The only method for determining the growth of tree species is by laying out permanent growth plots in which the same trees are measured at interval of time. 70 71 As part of East Kalimantan Forest Service's long term forest management plan, Gadjah Mada University has established 79 one-hectare permanent growth plots. These plots were established in 1977, located in recently logged over forest throughout East Kalimantan. In plot establishment, plot boundaries and trees along paths to the plots were carefully painted red to ensure that the plots could be found for subsequent measurement. All trees 100 mm diameter and up were numbered with aluminum tags nailed to the tree above the point of measurement (1.30 m). At the point of measurement was painted a ring at 1.30 m above ground level measured on the uphill side of the tree. For buttressed trees, the point of measurement was located at 20 cm above the buttress.~ Trees were identified as to species and their diameters measured with diameter tape to the nearest mm. In 1980, I mapped all the numbered trees. I remeasured their diameters with diameter tape to the nearest mm, measured basal area of tree's competitors by the Panama Basal Area Angle Gauge, and for the dipterocarp species were measured the distances from the opening to the nearest dm. . I used program drum, a special attachment to the IBM 026 keypunch to punch more than 10,000 fortran cards. The card placed on the drum can be set up to allow the IBM 026 key- punch to duplicate automatically or skip unused columns of 72 a card. I rearranged the contents of my file by species. I used sorting machine for this arrangement. After the file had been rearranged by species, I per- formed all computations by using Texas Instrument TI Pro- grammable 58 C calculator. I utilized this instrument because it can be afforded by people from concessions and forest service, so that they can follow my procedures. I summarized the procedure in the tabular form to make it ready to use. I found that there is a relationship between initial diameter and diameter growth. The larger the initial dia- meter, the greater the growth rate. The rate of change in growth rate with diameter varied among species, varying from .018 to .030 mm growth rate per mm of diameter. 50 did the inherent growth rate, as measured by the Y-intercept in the growth rate - diameter regression formula. Members of the upper story of first layer generally had the most rapid growth rates for trees of small to medium diameters and the lowest rates of change in the growth rate - diameter ratio. I also computed the effect of tree's competition on subject tree. The higher the basal area of competitors, the more intense the competition, and the greater the reduc- tion in diameter growth of the subject tree. I appraised diameter growth response of dipterocarp species under different crown release. My results indicated that opening by logging increased diameter growth of 73 individual tree in residual stand. I demonstrated how to estimate period of change from small diameter to large diameter. The data are presented in two forms: (1) the number of years needed for trees of 20, 30, etc. cm diameter to reach 30, 40, 50, etc. diameter, and (2) the diameter growth of trees of a given size during the next 15, 25, or 35 years. Such data are presented for each of several commercial species. It is of interest to estimate the amount of cut for the next cutting cycle. To do this, I counted the numbers of trees on the study plots which will probably reach diameters of 50 cm or more in the next 35 years. On each of the three concessions it appears that the next cut will be about as heavy as the last cut. The above discussions suggest that it is about the time to establish growth plots on every concession. These plots have to be adequate for monitoring and forecasting the operations. Cooperation between concessions - forest service- universities - and research institute will accelerate and strengthen the program. REFERENCES CITED REFERENCES CITED Buol, S.W., Hole, F.D. and R.J. McCraken. 1973. Soil genesis and classification. Iowa State University Press, Ames. Central Bureau of Statistics. 1976. Statistical yearbook of Indonesia. 1976. Annual Statistics and Publications Division, Jakarta, Indonesia. Crow, T.R. and P.L. Weaver. 1977. Tree growth in a moist tr0pical forest of Puerto Rico. Institute of Tropical Forestry, Forest Service, U.S.D.A., Rio Piedras, Puerto Rico. Direktur Jendral Kehutanan. 1972. Surat Keputusan No. 35/ kpts/DD/I/l972 tentang pedoman tebang pilih Indonesia, tebang habis dengan penanaman tebang habis dengan permudaan alam dan pedoman-pedoman pengawasannya. Departemen Pertanian, Kirektorat Jendral Kehutanan, Jakarta, Indonesia. Directorate of Forest Inventory and Planning, 1968. A Report on the S. Kajan-S. Kelai forest survey, East Kalimantan Province. Directorate of Forest Inventory and Planning, Bogor, Indonesia. Dawkins, H.C. 1956. Rapid detection of aberrant girth increment of rain forest trees. Empire Forestry Review 74 75 35:449-454. Dawkins, H.C. 1959. The volume increment of natural tr0pica1 high forest and limitations on its improvement. Empire Forestry Review 38:175-180. Forest Products Marketing Development Project. 1978. Timber in Indonesia. Directorate Jendral of Forestry, Jakarta, Indonesia. Foth, H.D. and J.W. Schafer. 1980. Soil geography and land use. John Wiley & Sons. New York. Fox, J.E.D. 1970. Yield plots regenerating forests. Malayan Forester 33:7-41. Jordan, C., Galley, F., Hall, J. and J. Hall. 1980. Nutri- ent scavenging of rainfall by the canopy of an Amazonian rain forest. Biotropica 12(1):61-66. Kato, R., Tadaki, Y. and H. Ogawa. 1978. Plant biomass and growth increment studies in Pasoh Forest. Malayan Nature Journal 30:211-224. Miller, Th. 8. 1980. Growth and yeild of logged over mixed dipterocarp forest in East Kalimantan. Paper presented in seminar on Dipterocarpaceae in Malaysia, 1980. Murphy, P.G. 1970. Tree growth at E1 Verde and the effects of ionizing radiation. 1__H.T. Odum (ed.) A Tropical rain forest. pp. 0 141-0 171 Division of Technical Infor- mation U.S. Atomic Energy Commission. 76 Nicholson, 0.1. 1958. One year's growth of Shorea smithi- .333 in North Borneo. Malayan Forester 21:193-196. Osmaston, H.A. 1956. Determination of age/girth and similar relationships in tropical forestry. Empire Forestry Review 35:193-197. Poore, M.E.D. 1968. Studies in Malaysian rain forest. I. The forest of triassic sediments in Jengka Forest Reserve. J. Ecol. 56:143-196. Prince, A.J. 1973. The rate of growth of greenheart (0c0tea rodiaei). Commonwealth Forestry Review 52:143-146. Setijono 33 31. 1979. Laporan penelitian pembinaan dan pengembangan tebang pilih Indonesia tahun anggaran 1978/1979. Fakultas Kehutanan Universitas Gadjah Mada & Dinas Kehutanan Propinsi Kalimantan Timur. Soil Survey Staff. 1975. Soil taxonomy. U.S.D.A. Agri- culture Handbook 436, Washington, D.C. Soekotjo 33 31. 1976. Penelitian pelaksanaan "Tebang Pilih Indonesia" dan intensifikasi pengawasan exploitasi hutan di Kalimantan Timur. Fakultas Kehutanan Universitas Gadjah Mada, Yogyakarta, Indonesia. Soekotjo and 0.1. Dickmann. 1978. The effect of Indonesian Selective Logging on natural regeneration in East Kali- mantan rain forest. Voluntary paper, FID-I/18-12-Eighth World Forestry Congress, October 16-28, 1978, Jakarta, Indonesia. 77 Sulit, C., Asiddao, F. and M.R. Reyes. 1962. Growth of tropical forest with special reference to the Philippine dipterocarp forest. Philippine J. Forestry 18:69-91 Syachrani, Buyahmin and Soekotjo. 1974. Suatu analisa pengaruh penebangan secara mechanis terhadap kerusak tegakan tinggal jenis komersiil di PT Kutei Timber Indo- nesia, Kalimantan Timur. Seminar on Reforestation and Afforestation Fakultas Kehutanan, Universitas Gadjah Mada, pp. 147-157. Vincent, A.J. 1961. A note on the growth of Shorea macrop- 3333 (Meranti melantai). Malayan Forester 24:190-209. Vincent, A.J. 1962. A note on the growth of Shorea lumu- tensis (Balau putih). Malayan Forester 25:74-78. Wong, F.0. 1973. A study of the growth of the main commer- cial species in the Segaliud Lokan F.R. Sandakan, Sabah. Malaysian Forester 36:20-31. APPENDIX Appendix 1. 78 Common names used in this dissertation and their approximate scientific names and families Common names Scientific names Family Api Bagtikan Balau putih Bangkirai Banitan Jambu Kapur Kapur tanduk Kayu arang Kempas Keruing Keruing tempurung Keruing hijau Lalan Langsat Lempung abang Marakeladi Margaram Margelang Marjelawat Medang Mendarahan Merkabang Parashorea p1icata Shorea lumutensis Eushorea (Sub genus) Polyalthia spp Eggenia spp Dryobalanops spp Dryobalanops lanceolata Dio3pyros spp Koompassia malaccensis Dipterocarpus spp Dipterocatpus caudiferus Dipterocarpus_ggandi- florus Santiria laevigata Lansium spp Shorea ggiso Polyalthia lateriflora Litsea Linociera spp SPP Shorea §guamosa Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae Annonaceae Myrtaceae Dipterocarpaceae Dipterocarpaceae Ebenaceae Leguminosae Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae Burseraceae Meliaceae Dipterocarpaceae Annonaceae Euphorbiaceae Lauraceae Myristicaceae Dipterocarpaceae Appendix 1. 79 (continued) Common names Scientific names Family Meranti almon Meranti gisok Meranti merkuyung Meranti merah Meranti tembaga Mersawa Nyerakat Nato Red meranti Resak Seraya melanti Temberas Ulin Urat mata Urat mata hijau White meranti Yellow meranti Shorea almon Shorea gisok Shorea leptoclados Shorea negrosensis Shorea 13prosula Anisoptera thurifera Hopea spp Palaquium spp Rubroshorea (Subgenus) Cotylelobium spp Shorea macroptera Memegylon spp Eusideroxylon zwageri Parashorea p1jcata Parashorea tomentella Anthoshorea (Subgenus) Richitia (Subgenus) Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae Sapotaceae Dipterocarpaceae Dipterocarpaceae Dipterocarpacea Melastomataceae Lauraceae Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae Dipterocarpaceae "11131111111133is