Structural model of sandalwood (Santalum album) regeneration in the forest and community plantation in Timor Island, Indonesia

Abstract

Abstract. Seran YN, Sudarto, Hakim L, Arisoesilaningsih E. 2018. Structural model of sandalwood (Santalum album) regeneration in the forest and community plantation in Timor Island, Indonesia. Trop Drylands 2: 41-47. Sandalwood (Santalum album L.) is a very important forest product in Nusa Tenggara Timur (NTT) Province, Indonesia due to its high economic value. However, the population of sandalwood is threatened, requiring regeneration to enhance its population. This study aimed to identify and produce a structural model of sandalwood regeneration in both natural forest and the community plantation in the districts of Timor Tengah Selatan (TTS) and Timor Tengah Utara (TTU), NTT Province. The method used in this research was vegetation analysis using purposive sampling method at 8 observation stations with total of 87 plots. The plot size was 20x20 m² (trees), 10x10 m² (poles), 5x5 m² (saplings), and 2x2 m² (seedlings). Data observed in the field included the mean sandalwood population size in the forms of trees, poles, saplings and seedlings phase; vegetation data in sandalwood habitat which included tree wealth index, diversity index, number of individuals and sandalwood host diversity index data. Geographical factors such as altitude and slope, and abiotic factors such as soil organic matter, soil pH and soil conductivity were also recorded. Climate data included the number of dry months and rainfall. Sandalwood regeneration data included sandalwood vitality, pests and diseases, and the number of seeds. Secondary data included climate data (ten years time) obtained from BMKG. Altogether, these data were used as the indicators of the latent variables (six variables) which consisted of geography, soil, climate, population, vegetation, and regeneration. Obtained data were subjected to both descriptive analysis and multivariate statistics with structural modeling of Warp Partial Least Square (WarpPLS 6.0). The results showed that most of the proposed indicators significantly influenced the six latent variables except the host diversity. Some indicators significantly or highly significantly affected the latent variable with 15 indicators that significantly composed the latent variable. The resulting structural model had of Q2 predictive value of 96,65%, suggesting that the structural model proposed in this study has very relevant and high prediction on factors that influence sandalwood regeneration. Therefore, this model is feasible to be used as recommendations in the framework of sandalwood development in the forest and the community plantation in the West part of Timor Island, Nusa Tenggara Timur.