ON THE STATISTICAL ANALYSIS OF REPRODUCTIVE SIZE THRESHOLDS IN DIPTEROCARP FORESTS

Abstract

In a recent publication, evidence was presented that smaller trees can fruit in logged dipterocarp forests in Peninsular Malaysia. Here we point out an important statistical flaw in the paper: namely, that the mean size of fruiting trees in logged forest may he depressed simply due to the removal of larger individuals during harvesting. An improved analysis is presented, based on estimation of the reproductive size thresholds of trees using a modified form of logistic regression. We conclude that there is insufficient, evidence to strongly support the idea that trees fruit at smaller sizes in logged forest; however, there is a suggestive trend in this direction. Guidelines are given for further data collection and analysis to definitively answer this important question.