TREE VEGETATION DYNAMICS IN THE BATU MEJA PERMANENT PLOT, PANANJUNG NATURE RESERVE PANGANDARAN.

• Main Author: Aulia Zahrah, Azza
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85665
• Institution: Institut Teknologi Bandung

In 2010, a 1 Ha permanent plot was established in Batu Meja area, Pananjung Pangandaran Nature Reserve which is currently undergoing natural succession from grassland to secondary forest. Observation of the permanent plot is important to see the dynamics of vegetation during the succession process and also to see the influence of environmental conditions on the vegetation within it. Vegetation monitoring in these permanent plots has been conducted in 2010, 2011, 2013, 2017 and 2024. The 1 Ha plot was divided into 100 subplots, each measuring 10x10 m2. The plot's zero point was marked with a plastic pole to indicate the subplot numbers. Trees with diameter at breast height (DBH) ? 4.8 cm were measured, their position coordinates within the plot were recorded, marked with paint and given a number plate if the tree was recorded as recruitment or the number plate was lost. The number of new individuals and dead individuals were counted to measure tree recruitment and mortality. The importance value index (IVI), Shannon-Wiener diversity index (H'), recruitment rate, mortality rate, and growth rate were calculated for each species. Over the 14 years of monitoring, the number of species in the permanent plots increased from 62 to 75 species with H' from 2.9 (2010) to 3.2 (2024). This increase in species richness was followed by a change in species composition within, although trees were still dominated by Syzygium lineatum (IVI = 48.04%) and Rhodamnia cinerea (INP = 36.34%). Plants common in early successional periods such as Psychotria cf. robusta, Glochidion rubrum, Cryptocarya densiflora disappeared in the 2024 measurements and were replaced by tree species common in advanced successional forests such as Dillenia excelsa (114 individuals), Ficus sumatrana (1 individual), and Pentace polyantha (60 individuals). Tree species recorded as new recruits are Bacauria javanica (10 individu) and Dysoxylum amuroides (4 individu). Based on diameter class data, the number of individual trees with a diameter of 4,8-10 cm is very high compared to other diameter classes. Trees that have the highest growth rate (IDi) are D. excelsa at 2.30 cm/year and F. sumatrana at 2.27 cm/year at a diameter (DBH) of >30 cm, while in the diameter class 4.8-10 cm Vitex pinnata has the highest growth rate of 0.51 cm/year. Pioneer trees can grow quickly and help form shade and facilitate other plants to grow in permanent plot areas so that the suscession process can run. The recruitment rate from 2017 to 2024 was the highest at 20.83% with the most species recruitment coming from Pentace polyantha (36 individuals) and S. lineatum (35 individuals). The high recruitment rate was likely influenced by the formation of gaps that arose due to the high mortality rate from 2017 to 2024 of 28.79%. Rhodamnia cinerea was recorded as the tree with the highest mortality of 152 individuals. The large number of young individuals, along with the presence of tree species commonly found in lowland forests, suggests that the forest is in good condition and is progressing towards an older secondary forest.