Vegetative and reproductive phenology of Aquilaria malaccensis Lam. (Agarwood) in Cachar District, Assam, India

Abstract

Aquilaria malaccensis Lam., a threatened tree commonly called agarwood, is emerging as one of the most promising commercially important aromatic species in the world. This paper presents the findings on the vegetative and reproductive phenology of Aquilaria malaccensis from the secondary tropical evergreen forest in Cachar district, Assam. The effect of tree phenology and the influence of seasonal drought and environmental variables, especially temperature and precipitation, on various phenophases such as leaf initiation, leaf-fall, flowering, and fruiting were investigated. For this, a quantitative assessment was made at 15-day intervals by tagging 35 trees over a period of two years. Seasonal influence on the phenology of different phenophases was correlated with environmental variables and Spearman's rank correlation coefficient was employed. Leaf initiation was positively correlated with temperature (rs=0.694, p= < 0.05), while leaf-fall was negatively correlated with temperature (rs=-0.542, p= < 0.05) and rainfall (rs=-0.521, p= < 0.05). Flowering (rs=0.713, p= < 0.01; rs=0.713, p= < 0.01) and fruiting (rs=0.721, p= < 0.01; rs=0.775, p= < 0.01) were positively and significantly influenced by temperature and rainfall. The study suggests that temperature and rainfall were major determinants of the vegetative and reproductive phenology of A. malaccensis, and any changes in these variables under expected climate change phenomenon may have a profound effect on phenophases of this threatened tree species.