Timber Yield and Quality Assessment of Plantation-Grown Teak (Tectona grandis) in Ife-Ijesa Forest Reserve, Osun State

Teak (Tectona grandis) plantations represent a strategic timber resource for Nigeria's wood products industry, yet systematic assessment of yield and quality characteristics across plantation ages remains insufficient to support evidence-based harvesting decisions. This study assesses stand-level timber yield, bole quality, and wood density of teak plantations at three age classes (15, 25, and 35 years) in Ife-Ijesa Forest Reserve, Osun State. Circular sample plots of 0.04 hectares were established in eighteen blocks, with all trees measured for diameter at breast height, total height, commercial bole length, and quality defects (forking, leaning, pest damage). Wood density was determined from increment core samples using the water displacement method. Yield tables were constructed from stand basal area and volume equations previously validated for Nigerian teak. Results show mean annual increments of 8.7, 10.2, and 9.4 cubic metres per hectare per year for the 15, 25, and 35-year stands respectively, indicating peak productivity in the mid-rotation period. Bole quality improved significantly with age, with the 35-year class yielding the highest proportion of premium grade logs. Wood density showed a weak positive relationship with age class, remaining within industry-acceptable ranges. The study recommends rotation extension to 30-35 years as economically and ecologically optimal for teak in this ecotype. Keywords: teak plantation, timber yield, bole quality, rotation age, Osun State