Vegetation Analysis of the Middle Slope Geomorphic Units on the Southern Flank of Mount Merapi

Merapi is an active volcano located in the border between DIY and Central Java. The eruption of Mount Merapi has changed the soil conditions as well as the surrounding vegetation. This study was aimed to identify the vegetation distribution shaped after the 2010 eruption in the geomorphic units of the middle slopelocated in the southern flank of Mount Merapi. This study was carried out through survey followed by descriptive and spatial analysis. Vegetation distribution was evaluated by determining density value, frequency, dominance, importance value index and diversity index. Middle slope geomorphic units, Southern flankconsidered as disaster-prone areas zone II and III, were covered by 33 species composed of 209 individuals. Of all species found, the most abundant species were chinese albizia (so-called sengon ) ( Albizia chinensis ), mahogany ( Swietenia mahogany ) and green wattle ( Acacia decurens ). The abundance of these three species was indicated by its high importance value index associated with high adaptability of the species, even grown in the eruption-affected areas.