Komposisi dan struktur vegetasi pada areal hutan bekas terbakar (di areal UPT Taman Hutan Raya R. Soerjo, Malang)

Abstract

I NTRODUCTION. Forests damage in Indonesia are increasing affect to forest function decline. One cause of forest destruction in Indonesia is forest fires. Forest fires in Indonesia are mostly caused by humans. Impact of forest fires covering all aspects of ecosystems like, vegetation, fauna, soil, water, climate, air, and humans. forest vegetation damage caused succession in burned area. Succession effect reflected on forest vegetation composition dan structure. METHODOLOGY. The research was conducted in unburnt forest area, forest areas with a mild fire level, forest area with medium fire level, and forest area with heavy fire level. In each site observations made in three plots with plot size 100 x 100 m. In each plot observations are made of 4 sub-plots sample with size 20 x 20 m to measure the level of tree, strangler and woody liana; size 10 x 10 m to measure the level of the pole; size 5 x 5 m measure the level of saplings, lianas non-wood, pine, and palm; and 2 x 2 m measure the level of seedlings, ferns, shrubs and herbs. RESULTS AND CONCLUSION. Forest fires in R Soerjo Forest Park, Malang resulted in a decrease number of species of trees and regeneration rate and growth form. Only herb that has a stable species number in all forest conditions. Shannon species diversity according to the Index of General Diversity (H') shows that forest fires reduced the value of diversity at the level of stakes, poles, trees and most other forms of non-tree growth. Forest structure in each forest condition have a different highest diameter class. Unburned forest conditions have diameter until up to 110 cm, mild level forest fires reached only 60-69 cm for the highest diameter class. Meanwhile, on the medium level forest fires reached 80-89 cm for the highest diameter class, while the diameter classes of forest with heavy fire levels only reached 40-49 cm. Forest fires reduce the value of density on all forest burned area. The effect of forest fire on soil chemical properties are decrease soil pH value, increase the value of C-organic, and increase the value of cation exchange capacity (CEC). Forest fire in R. Soerjo Forest Park Area, Malang is causing changes of forest vegetation composition and structure and also soil chemical properties.