Density variation in axial and radial positions of Caribbean pine (Pinus Caribaea Morelet) grown in Afaka, Nigeria

Abstract

The study was undertaken in Plantation grown Caribbean Pine (Pinus caribaea Morelet) in Afaka plantation, Kaduna State, Nigeria on variability (radial and axial) of basic wood density. In order to ensure efficient and sustainable utilization of this species apart from local supply of long fibre for pulp and paper making, it is important to look into the pattern of variation in its properties, hence the justification for this study. The trees selected were 5, 7, 15, 20 and 25 years old respectively. In each age group three trees were harvested with their total tree height and diameter at breast height measured. Discs of 5 cm in thickness were obtained at breast height. Additional bolts of 20 cm for pulping materials were obtained at base, middle and top of trees sampled in 15, 20 and 25 age series while the entire logs from 5 and 7 age series was used. Each disc was cut at the pith, smoothened and the number of rings was counted. Each disc was then divided into sections based on the ring numbers. The sections were soaked in distilled water for 36 hours to attain green volume and density was estimated by water displacement method. The results showed significant variation in wood density of P. caribaea from the pith to the bark as well as from the base to the top. Ring number 11-15 from disc at Diameter at Breast Height (DBH) showed the highest density value of 0.6489 kg/m³ while ring number 1-6 from disc at 50% total tree height had the lowest density value of 0.3811 kg/m^3. Axially, density decreases with increasing height along the log, but there is no significant difference in their values (p>0.05). From the findings, the radial variation in wood density of P. carribaea grown in Afaka is significantly different from the pith to the bark but no significant difference along the sampling height.