Komposisi Jenis dan Struktur Tegakan Hutan di Taman Nasional Gunung Ciremai, Jawa Barat

Abstract

INTRODUCTION. The existence of forest as an ecosystem is important for life supporting system. This is because the forest produces various benefits, either in the form of services or goods which are very useful for life. In West Java, as in other parts of Indonesia, forests which are still having relatively good condition, are found only in conservation areas. One of the forest conservation areas which is relatively large is Gunung Ciremai National Park (TNGC). The TNGC constitutes a nature conservation area which possesses important ecological function as life supporting system for the surrounding ecosystem. However, information concerning the existing biodiversity in TNGC is still lacking. Therefore, there is a need for more studies to obtain information on biodiversity level and forest composition and structure in TNGC. METHODOLOGY. This study was conducted from August through September 2008 in altitude zones of < 1.000 m above sea level (asl) (lowland zone), 1.000 – 2400 m asl (montane zone), and > 2.400 m asl (sub alpine zone) in Gunung Ciremai National Park, West Java. This study was performed by using vegetation analysis technique which constitutes combination between strip method for tree stage vegetation inventory and plotted line method for forest regeneration inventory. To ease the inventory process, each strip was divided into plots of 20 m X 20 m for tree stage vegetation inventory, 10 m X 10 m for pole stage inventory, 5 m X 5 m for sapling stage inventory, and 2 m X 2 m for seedling stage inventory. Units of vegetation sample plot were placed in west and south slope directions at altitude zones of < 1.000 m asl, 1.000 – 2.400 m asl, and > 2400 m asl. In each slope direction, two sample units with strip length of 200 m and width of 20 m were established. Sampling units were placed in the field with sampling design of systematic sampling with random start. RESULTS AND CONCLUSION. Sub alpine zone exhibited the least number of species (11 species) at all growth stages, as compared with those of montane zone (62 species) and lowland forest zone (58 species). The number of species in the montane zone was relatively greater as compared with that of lowland forest zone. In lowland zone, the dominant species were huru meuhmal (Litsea tomentosa) at seedling stage (IVI 33,7 %), kileho (Saurauia pendula) at sapling stage (IVI 29,3 %), and pine (Pinus merkusii) at pole and tree stages (IVI 144,7 % and 112.8 %). In the montane zone, the dominant species were huru meuhmal (Litsea tomentosa ) at seedling stage (IVI 22,6 %), Litsea sp. at sapling stage (IVI 19,4 %), walen (Ficus ribes) at pole stage (IVI 32.6 %) and saninten (Castanopsis argentea) at tree stage (IVI 45,4 %). At sub alpine zone, the dominant species was plending (Leucaena glauca) at seedling and sapling stages (IVI 64 % and 76,4 %), cantigi (Vaccinium varingifolium) at pole stage (IVI 124,3 %), and jamuju (Dacrycarpus imbricatus) at tree stage (IVI 138,3 %). Index of species diversity (H’) for all elevation zones in TNGC were categorized as high (H’ > 2). However, there was a tendency that the higher the elevation, the smaller was the number and diversity index of species. The interesting phenomenon was that lowland forest zone exhibited number and diversity index of species which were relatively lower than those of forest area in montane zone. This was because most of the forest territories in the lowland were converted to a large extent into cultivated farmlands for the people. Vegetation communities at all growth stages in the study location were relatively not similar in terms of species composition as shown by index of community similarity which was below 75 %. Average stand dimension in lowland zone showed total height of 19 m and diameter of 34,97 cm; whereas those in montane zone, the total height was 18 m and diameter was 42,23 cm; and in sub alpine zone, the total height was 15 m and diameter was 46,5 cm. Crown stratification analysis showed that pattern of crown stratifications in Gunung Ciremai National Park at all altitude zones could be categorized into three strata, namely stratum A (tree height > 30 m), stratum B (tree height between 20 – 30 m), and stratum C (tree height 4 – 20 m). As generally found in nature, dominant and codominant trees in forest territory of TNGC grew and spread in groups. Abundance of tree individuals decrease with increasing diameter of stems. This tendency of decreasing number of tree individuals, with increasing diameter, was shown by inverted J curve (negative exponential curve).