The Value of Periodic Girth Measurement Taken for Individual Trees of Single Species from Tropical Evergreen Rain forest, Malaya

In the tropical evergreen rain forest of the Malaya Peninsula, trees with visible growth rings are a rarity. To plan tentative rotations for individual species it is necessary to rely on increment data to give an estimated size on age relationship. The conclusion is drawn that to minimise other forms of bias it is necessary for girth increment data to be collected from individual trees growing in all-sized forest (Class A 'Linear plots'), which still gives an unavoidable bias in translation of results to the more regular crops of the first managed rotation.

The worth of results obtainable from analysis of the data available from permanent sample plots is reckoned insufficient to warrant the detailed method of investigation outlined by Setten (1954) for Malayan forestry, and a method due to Griffith and Prasad (1949, Method II) is preferred for its simplicity, reality and speed of analysis. The available data for Dryobalanops aromatica (kapur) have been used in the comparative analyses from which these conclusions were drawn.

Finally, it is recommended that all routine annual field measurement for girth of selected individual trees on the subjectively sited plots on an area basis in naturally or artificially regenerated forest, and of trees individually selected in plantations, be stopped because the data obtained from them contain bias which cannot be satisfactorily eliminated in analysis. Subsequent to completion of analysis of data from trees individually selected in all-sized forest, if considered necessary a scheme should then be designed on the basis of Class A Linear plots laid down at staggered time intervals in stratified a11- sized forest, for collection of data for species reckoned of sufficient importance to warrant individual attention, to enable planning of tentative rotations.