Vol. 9 No. 2 (2003)
Lowland Tropical Rain Forest in Forest concession (HPH) PT. Inhutani II, Stagen Pulau Laut, South Kalimantan, and in forest concession PT. Ratah Timber Co, are climax forest under dynamic equilibrium, which are dominated by tree species from Dipterocarps family. Mechanical logging which is conducted in forest concession area will result in the formation of forest with certain composition and structure. Recovery of the forest is left to proceed naturally and will take a certain amount of time, and will affect the next duration of rotation. From the simulation result which were made on the basis of data from permanen plot in area of PT. Inhutani II, it was found that respond of simulation or respond of logged over natural forest management system in permanen plot, revealed that cutting cycle I after logging require ± 24 years time, whereas cutting cycle II require ± 37 years time. Model obtained from simulation result which were made on the basis of data obtained from permanen plot in area of PT. Inhutani II, is used for data which were obtained from non permanen plot at forest concession area of PT. Ratah Timber Co. Respon of simulation from forest concession of PT. Ratah Timber Co reveal that cutting cycle I after logging require ± 30 years time, whereas cutting cycle II require ± 43 years of time. This Phenomena imply that cutting cycles, are not always constant and will change in line with the composition and structure of logged over natural forest and their development with time.
The study discribes a system model of natural forest on logged over areas under selective cutting and planting system. The study departs from a fact that disturbance of forest from logging activity will affect the equilibrium of forest ecosystem including the forest stand composition. The study was performed in the forest concession area of PT. Inhutani II, Pulau Laut South Kalimantan. From the simulation results derived based upon permanent plot data, it was found that respond of logged over natural forest management system revealed that cutting cycle I after logging requires approximately 24 years, where cutting cycle II requires approximately 37 years. This expresses that cutting cycles are not consist and will change in line with the composition and structure of logged over natural forest as will as their development.
System dynamic is an effort to understand complexity of social and eco-systems of forest. Through this system, a conscious learning on interaction between people and forest will take place in order to manage forest in more sustainable and equitable manners. A system dynamic modeling was carried out in area surrounding Lumut Mountain Forest, District of Pasir, and East Kalimantan. In the area, where legally was allocated to a logging company, live local people who depend on forest and rattan. The policy makers are trying to improve the well-being of local people without sacrifying the logging company. Aim of the study was to give policy options to policy makers and likely impacts of those options. The built model comprises biophysical, social, policy and impact main components. The model shows the change of impact indicators, which are standing stock, community income, and concession revenue and government income, given any selected policy option.
The objective of this research is to develop remote sensing and GIS techniques with hydrological approach for critical land identification and mapping. This research was done by weighting method using three variables, i.e., slope, runoff curve number and percent land cover derived from digital and visual analysis techniques. Critical land identification was known by integrating Runoff Curve Number resulted from combination of land use and Hidrological Soil Group, Slope and Percent Land Cover. Land use and Percent Land Cover information were derived from Landsat data, while Hidrological Soil Group results were from 1:50000 soil type map, and slope was from 1;25000 scale of topographic map. Critical land modelling was done using three parameters, slope, runoff Curve Number and percent land cover. This research examined thirteen a, b and c combinations. Mapping accuracy of the model was evaluated using erosion hazard based on USLE formula: A=RKLSCP. The study shows that remote sensing data can be used to produce land use/land cover for curve number prediction and land cover percent as critical land identicication and mapping variables, having accuracy of 62, 59 percent.
This study examined the capability of high-resolution imageries for identifying tree species. The IKONOS and CASI (Compact Airborne Spectrographic Imager) data were examined to digitally identify 20 tree species and estimating stand density. The numerical taxonomy using nearest neighbor hierarchical classification method was applied to cluster the spectral reflectance of those species of interest. Although the panchromatic band of IKONOS and CASI have the same spatial resolution, the study shown that CASI provided better performance than IKONOS in discriminating 20 tree species of interest. The finer spectral and spatial resolution of CASI significantly improved the quantitative discrimination ability. Inversely, the IKONOS imagery was fail to digitally identify tree species. However, the study shows that both the IKONOS and CASI images are capable to be used to estimate the stand density. To get a better result of discriminating 20 species using CASI image, the number of bands hould be used more than eight bands. Otherwise, some "inseparable" class pairs could exist.
Keywords: CASI, IKONOS, Separabilitas, Klaster