Predicting spacing effects on growth and optimal rotations of tropical multipurpose trees
1996
Harrington, R.A. | Fownes, J.H.
In order to improve our ability to analyze growth of tropical fast-growing trees, we developed a simple model (MPTGro) to predict development of even-aged stands from allometric equations of leaf area and total biomass, and a competition index based on wood production per unit leaf area, or net assimilation rate (E). In this study we (1) tested the model assumption that our competition index is valid across plant spacings, (2) tested the performance of MPTGro on two species of tropical multipurpose trees, and (3) applied the model to optimize rotations based on tree size, biomass allocation, or annual biomass increment. Measurements of E and stand leaf area index (LAI) at three-month intervals in spacing trials of Acacia auriculiformis and Leucaena diversifolia supported the assumption that a single relationship between E and LAI would explain growth at a variety of planting densities. Increasing plant density in the simulations decreased time until maximum mean annual increment (MAI) and diameter at maximum MAI, but increased leaf:wood biomass ratio at maximum MAI.
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