Crown diameter models for Tectona grandis (Linn. f.) in Agan forest plantation, Makurdi, Nigeria

Abstract

Crown diameters are not easy to measure in a forest stand. Individual tree crown diameter models was developed for Tectona grandis in Agan forest  plantation using crown-diameter and bole-diameter at breast height (dbh) over bark as predictor variables. Five sample plots were selected randomly in  the plantation and the trees with dbh above 10cm in each plot were measured using diameter tape and crown diameter was also measured. Each plot  size was 20m X 20m. The crown diameter range of 10.01 – 11.00m had the highest frequency. Simple and Multiple linear regression analyses were used  to relate the dependent and independent variables. The selected models involved an untransformed and transformed single entry crown diameter model  with Multiple linear (model 5) and (model 6) as the best fitted models for the relationship between crown diameter and diameter at breast height  of the forest plantation of Tectona grandis of Agan forest.