Crown ratio is the ratio of live crown length to tree height. It is often used as an important predictor variable for tree growth equation. It indicates tree vigor and is a useful parameter in forest health assessment. The objective of the study was to develop crown ratio prediction models for Tectona grandis. Based on the data set from the temporary sample plots, several non linear equations including logistics, Chapman Richard and exponential functions were tested. These functions were evaluated in terms of coefficient of determination (R 2 ) and standard error of the estimate (SEE). The significance of the estimated parameters was also verified. Plot of residuals against estimated crown ratios were observed. Although the logistic model had the highest R 2 and the least SEE, Chapman-Richard and Exponential functions were observed to be more consistent in their predictive ability; and were therefore recommended for predicting crown ratio in the stand.

Tree crown is one complement of net primary production and its dimensions reflect general tree health. Crown diameter is often used as an important predictor variable for tree growth equation. The objective of the study was to develop parsimonious crown diameter prediction models for Tectona grandis (Linn F. Verbenaceae). Based on the data set from the temporary sample plots, several equations including linear, parable, cubic, power, growth and exponential functions were tested. These functions were evaluated in terms of coefficient of determination (R2) and standard error of the estimate (SEE). The significance of the estimated parameters was also verified. Plots of residuals against estimated crown diameter were observed. The power model had the highest R2 and the least SEE compared with the other models. It is therefore recommended as a parsimonious model for predicting crown diameter in the stand.Key Words: crown diameter, tree growth variables, modeling, Tectona grandis