Abstract

Leaf phenology and seasonal patterns of basal area increment of teak [Tectona grandis] were studied in 6-8 year old plantations protected from the two most common teak insect pests (Hyblaea puera and Eutectona machaeralis) in Karulai Range, NilamburForest Division. In general, flushing began in late March and was completed by late April. Most leaf fall occurred during December to February. The rate of increment of basal area (estimated from girth at breast height measurements) followed a bell-shaped annual curve with most growth occurring in June, July, August and September, when the monthly increment average 3. 8 cm2 per tree. The results are discussed in relation to damage caused by H. puera, which causes defoliation in May-July, and is, therefore, more likely to have an impact on growth then E. machaeralis, which causes defoliation in December and January. These conclusions have been confirmed by other field observations [KFRI Research Report (1985) No. 30]