The abundance and importance value of tree in "Sendang Kalimah Toyyibah" surrounding and its implication to the spring

One important factor affecting sustainability of spring is composition of vegetation around it. "Sendang Kalimah Toyyibah" is one of many springs in Semarang with intensive utilization. Vulnerability of spring can be monitored by dominant vegetation species indicated by vegetation importance value indices, especially for tree. This research aimed to study the variation of tree species around "Sendang Kalimah Toyyibah", to analyze the importance value index of tree species and to analyze the implication of tree species which had dominant importance value index on "Sendang Kalimah Toyyibah" spring. Data collection was conducted via line transect with the length of 200 m on 4 directions which were defined based on the stream direction and the spring as the central point. Each transect has 4 observation plots occupying 20 x 20 m². Data collection was including tree species, abundance, presence frequency and basal area of tree. Data analysis was conducted for vegetation importance value index. The result showed that around "Sendang Kalimah Toyyibah" there were 28 tree species inwhich the abundance was dominated by Mahogany (33 individuals stands), Albizia (31 stands), Coffee (20 stands), Coconut (18 stands), Mangosteen (16 stands) and Banana (16 stands). Vegetation importance value index around "Sendang Kalimah Toyyibah" was dominated by the above 7 treeswith important values (IV) respectively species including Mahogany (28,97%), Albizia (26,70%), Mangosteen (23,47%), Java Black Bamboo (22,18%), Coffee (19,23%), Coconut (17,98%) and Durian (16,41%). Cumulatively, these 7 treesspecieses dominated the importance value of tree around "Sendang Kalimah Toyyibah" which was 154,95%. These dominant species had represented the ecosystem function in infiltration, filtration and absorption of water which were required for spring ecosystem sustainability.