Productivity and mortality of Acacia mangium willd. plantation with associated bark beetle and Nitidulid beetle in east Kalimantan, Borneo, Indonesia

Acacia mangium Willd. is one of the most common tree species in industrial forest plantations in Indonesia. This tree species can grow rapidly in a wide range of soil conditions, and its wood properties are very suitable for the growing pulp and paper industry in the country. However, this tree species is also known to have high mortality due to tree diseases. Since 2011, 512 permanent sampling plots have been repeatedly measured to evaluate the development of A. mangium plantations in East Kalimantan. The sampling plots were established across a range of site conditions that varied in topography, soil physical characteristics, and soil nutrient content, as well as using different provenance and tree spacing. In this study we found that productivity and mortality of A. mangium in this area was comparable to other studies in humid tropical forest plantations, with survival 6 years after planting lower than 50 percent. The result of this study showed that provenance was an important variable in survival models of A. mangium. However, survival and mortality models that were developed in this study were not good enough to make prediction owing to irregular mortality in the study area, causing high variability in the dataset. There were trends on decreasing productivity and increasing mortality of A. mangium through time that might be related to Ceratocystis wilt. Log extraction identified some bark beetle and sap-feeding beetle that can be potential insect vector of ophiostomatoid fungi and other pathogenic fungi on tree species. However, further study needs to be done to confirm if these beetles transmit the disease to A. mangium in the forest plantation in East Kalimantan, Borneo, Indonesia.