The population and distribution of agarwood producing tree (Aquilaria malaccensis) in Riau Province

Riau is recorded as one of the distribution areas of Aquilaria malaccensis, and has the largest export quota of agarwood in Indonesia. In this study, we identified the species distribution and abundance of the population of agarwood producing trees in the nature. The aims of the research were (i) to determine the distribution and abundance of A. malaccensis (ii) identification of ecological factors (microclimate and soil nutrients) and analysis of their relationship to abundance. Seven locations of agarwood producing trees were selected: Taman Hutan Raya (TAHURA: Forest Park Garden) Sultan Syarif Hasyim (SSH), three community forests in Siak Sri Indrapura Regency (Gosib, Perincit, and Dosan), and three community forests in Bengkalis Regency (Langkat, Pangkalan Jambi, and Duri Km 13). Random plots were established in the study sites and environmental parameters such as soil moisture, soil pH, temperature, humidity, and the soil macronutrients data were recorded. Aquilaria malaccensis planted at TAHURA SSH recorded about 38 individual ha-1 , with an average diameter was 15 cm, and the average tree height was 9.51 m. Perincit showed the highest density in wild condition with 8.13 individual ha-1 , with an average diameter was recorded for 20.8 cm and the average tree height was 9.11 m. While the lowest tree density was recorded of 0.58 individual ha-1 in Gosib; the average diameter and tree height were recorded of 40.15 cm and 14.70 m, respectively. The results of the study provide information in the conservation efforts of A. malaccensis through the possibility of planting it in various environmental conditions in Riau Province and land management such as being planted in monoculture or agroforestry systems as well as the ability to be reintroduced into species-rich natural forest. The supporting data gained from this study was used to provide information on location of potential seeds source and seedling. Moreover, the nutrient content as reviewed in this research will also be essential information about the needs of nutrient content in agarwood plantations.