RESULT AND DISCUSSION 1 Tree individual increment

Bogor, 21-22 October 2015 508 Individual increment calculation based on the average diameter increment cm 2th-1 and increment by basal area of stands m 2 ha -1 2yr -1 . rd i = d o – d i where as: rd i = tree diameter increment cm 2yr -1 d o = tree diameter on initial measurement cm d i = tree diameter on next measurement after 2 years cm rBD i = bd o – bd i where as: rBD i = basal area increment of stand m 2 ha -1 2yr -1 bd o = basal area of stand on initial measurement m 2 ha -1 bd i = basal area of stand on next measurement 2 years m 2 ha -1 Increment calculation done by grouping Dipterocarpaceae, non Dipterocarpaceae and all species. Rate differences forest conditions against individual increment and increment of stands using analysis of variance ANOVA. The relationship between the period of the second increment value is carried out by regression analysis. Regression equations were tested are as follows: Y = + X Linear Eq.1 Y = + 1 X + 2 X 2 Polinomialkuadratik pangkat 2 Eq.2 Y = + 1 X + 2 X 2 + 3 X 3 Polinomialkuadratik pangkat 3 Eq.3 Y = е X Eksponensial Eq.4 Y = + logX Logaritma Eq.5 Selection of the most appropriate model is done with a scatter diagram technique is based on the value of the correlation coefficient r and coefficient of determination R2 and the highest value of the standard error SE, the smallest Steel and Torrie, 1995. 3. RESULT AND DISCUSSION 3.1 Tree individual increment Logged over forest HBT after17 years of logging with conventional techniques have the average diameter increment value range for all types of wider ie 0.35-1.69 cm 2th-1, compared with RIL techniques 50 0:37 to 1:45 cm diameter increment flats 2th- 1 or with RIL techniques 60 0:41 to 1:31 cm diameter increment flats 2th-1. This suggests the existence of a relationship or the intensity of harvesting techniques on the response of individual increment in the stand. In the primary forest conditions, increment of individual trees of all kinds will be smaller than the logged forest conditions Table 1. Based on the composition of main component of stands in the main family groups and non Dipterocarpaceae, it generates the response value of the average increment of different individuals Figure 1. In general, the group has a diameter increment Dipterocarpaceae that greater than non Dipterocarpaceae on all forest conditions. The average diameter increment after logging would be greater than in primary forest conditions, mainly occurs because of the response to the opening of space after harvesting. These changes will increase the response since the 3rd year after logging and fluctuations throughout the year thereafter. On the condition of primary forest, dipterocarps tree individual increment greater than the group of Bogor, 21-22 October 2015 509 non Dipterocarpaceae. In this condition the increment of individual trees for all group types is lower than the logged forest conditions even without treatment. The approach for individual tree increment tree approach has flexibility for a wider projection on various range of conditions. For tropical forests, more complex structured growth model based on ecosystems, species composition and irrelevance high age variable Vanclay, 1995. So the equation is based on the diameter increment or basic areas that are reliable for use in suspect stands in total based on site conditions and the stand itself. Preliminary studies on the same research sites forests Labanan indicates diameter increment logged forest after two years is two times greater than the primary condition Nguyen-The et al., 1998, with the average diameter increment of primary forest stands of 0:22 cm th-1. Table 1: Periodic diameter increment cm 2yr-1 for all species Logging technique HBT1 HBT3 HBT5 HBT7 HBT9 HBT11 HBT13 HBT15 HBT17 cm 2yr -1 RIL50 Mean 0.37 1.08 1.06 1.00 1.45 0.81 0.69 0.76 1.04 SD 0.06 0.37 0.48 0.31 0.46 0.16 0.22 0.12 0.19 RIL60 Mean 0.41 0.88 0.93 0.80 1.31 0.67 0.61 0.68 0.98 SD 0.11 0.10 0.12 0.17 0.20 0.18 0.18 0.16 0.26 CNV Mean 0.35 1.27 1.27 1.11 1.69 0.86 0.88 0.79 1.26 SD 0.11 0.35 0.38 0.30 0.33 0.22 0.25 0.15 0.16 HP1 HP3 HP5 HP7 HP9 HP11 HP13 HP15 HP17 HP Mean 0.39 0.57 0.46 0.54 0.82 0.46 0.41 0.51 0.95 SD 0.10 0.16 0.11 0.22 0.16 0.12 0.12 0.12 0.16 Remarks: HBT = Forest after logging; RIL50 = Reduced impact logging 50 cm; RIL60 = Reduced impact logging 60 cm; CNV = Conventional logging 60 cm; HP = Primary forest; SD = Deviation standart Figure 1: Periodic diameter increment cm 2yr -1 on logged over forest with different technique for species group a Dipterocarpaceae dan b non Dipterocarpaceae The value of the average diameter increment in 10 provinces in Indonesia for a group of commercial species of 0.49-79 cm yr-1, non-commercial kind of 0.33-0.78 cm yr-1 and for all kinds of 0.38-0.79 cm yr-1 Suhendang, 2002 , Results of research in Brazil, Costa Rica, Guyana and Papua New Guinea with repeated measurements on permanent plots 3-10 years 1 2 3 1 3 5 7 9 11 13 15 17 P er io di c R d cm 2y r- 1 Period after logging years RIL 50 RIL 60 CNV HP 1 2 3 1 3 5 7 9 11 13 15 17 P er io dic R d c m 2y r- 1 Period after logging years RIL 50 RIL 60 CNV HP b a Bogor, 21-22 October 2015 510 at 11 study sites generate individual tree diameter increment th 0:15 to 1:36 cm-1 Alder et al., 2002. The value of individual tree diameter increment is in the same range with the results of this study, especially for groups Dipterocarpaceae. This shows the variation of the conditions of tropical forest stands have a range of tree diameter increment is quite wide. Cited in Silva et al. 2002 some of the results of research in tropical forests show that the annual diameter increment in Peninsular Malaysia amounted to 0.4-4.5 mm yr-1 Manokaran and Kochummen, 1993, in Panama amounted to 7.1-9.2 mm yr-1 Condit et al., 1995 , in the Tapajos Argentina is 2.0 mm yr-1 Silva et al., 1996; The Brazilian Amazon is 0:21 ± 1.64 mm yr-1 Gomide, 1997, in Costa Rica for 5-18 mm yr-1 Clark and Clark, 1999 and in Brazil at 0:48 to 11:41 mm yr-1. The results of this study using a different unit of measurement bias to reduce the increment is done every year. Measurement error due to the time measurement period is too short resulting in substantial bias. To reduce errors in the re-measurements, the optimum measurement period in logged forest is 2 years to stand with silviculture input and 3-year period to stand without treatment Suhendang, 1997. 3.2 Stand Increment Periodic Standing stock periodically based on the value increment of basal area of stands for all types in logged forest to 17 years with the average ranging from 0:27 to 2:10 m2 ha-1 2th-1. Different cutting techniques will produce value increment field different basic stand. Logged forest with conventional techniques logging the highest intensity has a basic range of the average value increment field that is wider ie 0:27 to 2:10 m2 ha-1 2th-1, compared with RIL50 techniques basal area increment average of 0.35-1.87 m2 ha-1 2th-1 as well as the techniques RIL60 basal area increment average of 0.42-1.67 m2 ha-1 2th-1. On the condition of primary forest, standing stock of all kinds will be smaller than the logged forest conditions even without treatment Table 2. Table 2: Periodic basal area increment m2 ha-1 2yr-1 for all species Logging technique HBT1 HBT3 HBT5 HBT7 HBT9 HBT11 HBT13 HBT15 HBT17 m 2 ha -1 2yr -1 RIL50 Mean 0.35 0.88 0.93 1.12 1.87 1.17 0.90 1.05 1.61 SD 0.09 0.17 0.24 0.28 0.60 0.22 0.33 0.14 0.26 RIL60 Mean 0.42 0.91 1.02 0.87 1.67 0.83 0.72 0.92 1.31 SD 0.14 0.14 0.21 0.17 0.35 0.11 0.22 0.17 0.24 CNV Mean 0.27 0.98 1.06 1.08 2.10 1.11 1.12 0.94 1.62 SD 0.07 0.13 0.18 0.17 0.36 0.30 0.23 0.25 0.18 HP1 HP3 HP5 HP7 HP9 HP11 HP13 HP15 HP17 HP Mean 0.51 0.71 0.54 0.67 1.05 0.57 0.48 0.65 1.28 SD 0.09 0.14 0.09 0.18 0.17 0.13 0.14 0.11 0.07 Remarks : HBT = Forest after logging; RIL50 = Reduced impact logging 50 cm; RIL60 = Reduced impact logging 60 cm; CNV = Conventional logging 60 cm; HP = Primary forest; SD = Deviation standart Based on the composition of the main component of stands in the main family groups of Dipterocarps and non Dipterocarpaceae, will generate the response value of different periodic increment of stands Figure 2. In general, non Dipterocarpaceae species group has the average increment of the basic fields 0:16 to 1:48 m2 ha-1 2th-1 is larger and wider range compared to the group Dipterocarpaceae 0:10 to 1:15 m2 ha-1 2th-1 in all conditions forest. The average increment of basal area of stands after felling will be greater than in primary forest conditions, mainly occurs because of the response to the opening of space to grow after Bogor, 21-22 October 2015 511 harvesting. These changes will increase the response since the 3rd year after felling. On the condition of primary forest, areas of basic stand increment Dipterocarpaceae 0:21 to 0:50 m2 ha-1 2th-1 will be smaller than the group of non Dipterocarpaceae 0.26-0.77 m2 ha-1 2th-1. The increment field correlated with the intensity of logging, but not always high-intensity logging will produce large standing stock. Differences in response to the periodic increment of basal area of each group of species based on variations in site conditions where grown have closeness in relation to the dimensions of the stand and the growth potential is determined by the interaction of heredity factors trees genetic, environmental factors that include climate temperature, light, wind, rain and land and silvicultural techniques given Kramer and Kozlowski, 1960; Husch et al., 1982; Oliver and Larson, 1996; Suhendang, 1990; Husch et al., 2003. Adam and Kolbs 2005 showed differences in the growth patterns of the same type at the same location, is strongly influenced by environmental factors include drought, temperature, slope and species composition. A significant relationship between the growth of individual trees and space to grow also describes the form of growth in the various states in the stands Gersonde and OHara, 2005. Figure 2: Periodic basal area increment m 2 ha -1 2yr -1 on logged over forest with different technique for species group a Dipterocarpaceae dan b non Dipterocarpaceae Table 3: Regression equation between period after logging and periodic diameter increment cm 2yr-1 for species group Dipterocarpaceae D, non Dipterocarpaceae nD all species SJ Species group Condition Equation R 2 SE P value D HBT y = 0.0022x 3 - 0.0649x 2 + 0.5331x + 0.0004 0.4126 0.3143 0.01 HP y = 0.0012x 3 - 0.0305x 2 + 0.2256x + 0.2087 0.3885 0.2107 0.04 nD HBT y = 0.0015x 3 - 0.047x 2 + 0.4147x - 0.1323 0.4014 0.2716 0.01 HP y = 0.0007x 3 - 0.0176x 2 + 0.1233x + 0.1567 0.3316 0.1419 0.03 SJ HBT y = 0.002x 3 - 0.0589x 2 + 0.4936x - 0.0439 0.4157 0.2919 0.01 HP y = 0.001x 3 - 0.0262x 2 + 0.1915x + 0.1914 0.3839 0.1837 0.01 Remarks: R 2 = coefficient determination; SE = error standart; HBT = Forest after logging; HP = Primary forest; x = Period after logging; y = Periodic diameter increment 0.0 1.0 2.0 3.0 1 3 5 7 9 11 13 15 17 P er io dic Rb d m2 h a- 1 2 yr -1 Period after logging years RIL 50 RIL 60 CNV HP 0.0 1.0 2.0 3.0 1 3 5 7 9 11 13 15 17 P er io dic Rb d m2 h a- 1 2 yr -1 Period after logging years RIL 50 RIL 60 CNV HP a b Bogor, 21-22 October 2015 512 3.3 Relationship between period after logging and increment periodic The analysis of variance ANOVA showed that the difference in the condition of logged forest to primary forest on a periodic diameter increment individuals to groups Dipterocarpaceae, non Dipterocarpaceae and all kinds of different shows significant results at the level of 95 Fcalc F table 3.32; 0.05 = 2.9011. While the difference between RIL harvesting technique 50, 60 and conventional RIL not provide a real connection to the diameter of the individual increment periodically for all types of grouping Fcalc F table 2.24; 0.05 = 3.4028. Based on these results in further analysis regression variation of conditions of logged forest with different logging techniques can be grouped into a single state forest stands are logged forest. Selected equation of regression analysis the relationship between the period of time after logging and periodic diameter increment value based on the correlation coefficient and determination as well as the highest standard of the lowest error for each group are presented in Table 3. The type of relationship pattern periodically based on the average diameter increment recovery period presented in Figure 3. Figure 3: Correlation between period after logging and periodic diameter increment cm 2yr -1 for species group Dipterocarpaceae D, non Dipterocarpaceae nD all species SJ on condition a forest after logging and b primery forest The analysis of variance ANOVA showed that the difference in the condition of logged forest to primary forest to the periodic increment of basal area of stands for all types of grouping Dipterocarpaceae, non Dipterocarpaceae and all kinds of shows results that are not significantly different at the 95 level Fcalc Ftabel 3.32; 0.05 = 2.9011. Similarly, the difference between RIL harvesting technique 50, 60 and conventional RIL on a periodic increment of basal area of stands for all types of grouping Fcalc F table 2.24; 0.05, = 3.4028. Based on the analysis of the variance in the regression analysis, the variation condition logged forest with different logging techniques can be grouped into a single condition that is logged forest stands alone. Selected equation of regression analysis the relationship between the period of time after logging and periodic basal area increment value is based on the correlation coefficient and determination as well as the highest standard of the lowest error for each group are presented in Table 4. The type of relationship pattern periodic increment field of basic stand by period recovery is presented in Figure 4. On the condition of forest stands after felling, the relationship period of time after logging have a relationship that is less than 50 of the value of the periodic diameter increment and increment of basal area of stands for all types of groups and non Dipterocarpaceae Dipterocarpaceae in the stands. Thus indicating the existence of other factors that play a role 0.0 1.0 2.0 3.0 1 3 5 7 9 11 13 15 17 P er iodi c R d c m 2y r -1 Period after logging years D nD SJ 0.0 1.0 2.0 3.0 1 3 5 7 9 11 13 15 17 P er iodi c R d c m 2y r -1 Period after logging years D nD SJ a b Bogor, 21-22 October 2015 513 in influencing the speed increment after logging. The opening of the canopy by logging will form a growing space that is conducive to growth or increase the rate of increment, either individually or in the stand. Optimal opening level to support optimal growth Gourlet-Fleury et al., 2005. Figure 4: Correlation between period after logging and periodic basal area increment m 2 ha -1 2yr -1 for species group Dipterocarpaceae D, non Dipterocarpaceae nD all species SJ on condition a forest after logging and b primery forest Table 4: Regression equation between period after logging and periodic basal area increment m ha-1 2yr-1 for species group Dipterocarpaceae D, non Dipterocarpaceae nD all species SJ Species group Condition Equation R 2 SE P value D HBT y = 0.0007x 3 - 0.0209x 2 + 0.1769x - 0.0197 0.4475 0.1266 0.42 HP y = 0.0005x 3 - 0.0134x 2 + 0.0991x + 0.1102 0.3844 0.0929 0.84 nD HBT y = 0.001x 3 - 0.0333x 2 + 0.3208x - 0.1367 0.3590 0.2769 0.05 HP y = 0.0008x 3 - 0.0207x 2 + 0.1431x + 0.1322 0.4531 0.1449 0.44 SJ HBT y = 0.0018x 3 - 0.0546x 2 + 0.5006x - 0.1604 0.4544 0.3434 0.12 HP y = 0.0014x 3 - 0.0341x 2 + 0.2422x + 0.2424 0.4971 0.2055 0.41 Remarks : R 2 = coefficient determination; SE = error standart; HBT = Forest after logging; HP = Primary forest; x = Period after logging; y = Periodic basal area increment Quantitative assessment of individual increment and increment of stands with a variation of conditions of forest stands after felling with different harvesting techniques showed different responses to the species species groups. The approach of grouping the type or dimensions of the different stands can be done to see the effect of the variation or group response to variations in the type of forest stand conditions after harvesting Harcombe et al., 2002; Seng et al., 2004. Different response from each species is one of the characteristics of a quantitative assessment of reviews are important dimensions stand for consideration variations in the diversity of types of constituent stands Phillips et al., 2002; Valle et al., 2006. With the availability of the estimation curve for input variables in the model as the quantitative growth of the forest planning will be better Vanclay, 1989. Ratings quantitative dimension in the long term is also beneficial for the evaluation of silvicultural techniques given and as updating forest inventory Garcia, 2001. By reviewing the characteristics of the constituent types of stands are important in studying the growth of trees is based on ecology and the establishment of quality tree Carvalho et al., 2004. 0.0 1.0 2.0 3.0 1 3 5 7 9 11 13 15 17 P er io dic Rb d m2 h a- 1 2 yr -1 Period after logging years D nD SJ 0.0 1.0 2.0 3.0 1 3 5 7 9 11 13 15 17 P er io dic Rb d m2 h a- 1 2 yr -1 Period after logging years D nD SJ a b Bogor, 21-22 October 2015 514

4. CONCLUSION