Diameter at breast height-crown width prediction models for Parkia biglobosa (Jacq) R. Br. ex G. Don.

This study was carried out in Kano state, Nigeria with the objective of predicting crown width from diameter at breast height and the planting spacing of Parkia biglobosa (Jacq) species. This is an economic plant with multipurpose usage. This species is exposes to degradation, overexploitation and have a regeneration problems. There is lack of information on inventory for P. biglobosa (Jacq) in term of plantation establishment and management. Data from the economic tree species were collected from nine plots (sizes 100 x 100 meters each), randomly laid down. Data on trees diameter at breast height (dbh) and crown diameter were collected from each plot within the study area. The data collected were tested on five crown and stem diameter relationship models. The simple linear model was best fitted with R² values of 0.69 to 0.85. The results shows that a dominant free-growing tree species with diameter 50.66 cm would require 0.0066 hectare of growing space with a stocking of the stand in terms of total occupancy by tree crowns of 151 trees per hectare. For optimum planting distance, fast growth and high production/yield, P. biglobosa would require a planting spacing of 4 x 4 meters (for NTFPs purpose) and 8 x 8 meters (for timber purpose). Thus, the baseline information from this study could serve as a guide for optimum planting distances and tree density in large scale plantations for countries with similar species and forest types.