THINNING GUIDELINES FOR TREE SPECIES OF DIFFERENT SUCCESSIONAL STATUS

Abstract

Four species of different successional status (Albizia falcataria = Parasfrianthes falcataria, Alstonia macrophylla, Mirchelia champaca and Swietenia macrophylla) were surveyed to construct spacing and thinning guidelines for their establishment in plantations in central and southwest Sri Lanka The species selected are commonly planted as shade trees in Kandy district and all have desirable timber properties. Tree measurements taken were diameter at breast height and crown width. These parameter's were sampled on trees located in stands of different density. Sixty individuals were selected that represented all size classes and stand densities for each species. Data of diameter breast height and crown width were used to construct spacing and thinning guidelines that were compared among species. Results showed that each species uses growing space differently under contrasting size classes. Guidelines based on these relationships are appropriate for species that are being introduced into new plantation systems where spacing and thinning information from permanent plots is not available. Maximum crown width can also be used to evaluate appropriate plant spacing of successionally compatible mixtures of tree species in a plantation.