Allometry  of  woody  biomass  and  leaf area  in  five  tropical  multipurpose  trees

R. A .  Harrington; J. H .  Fownes

Allometry of woody biomass and leaf area in five tropical multipurpose trees

1992

R. A . Harrington | J. H . Fownes

To derive allometric equations for leaf area andwoody biomass, and to test for differences due to tree age and planting density andgeometry, two field experiments were conducted on the island of Maui using Acaciaauriculiformis, Acacia mangium, Eucalyptus camaldulensis, Gliricidia septum and Leucaenadiversifolia. In the first experiment, harvest at 6, 12, 18 and 24 months of a 2 x 1 mspacing showed that woody biomass allometrics did not differ for any of the speciesover time. Leaf area equations differed among harvests for G. sepium due to seasonalleaf shedding, and for L. diversifolia, due to episodic psyllid attack, but did not differfor the other species. A second series of plots containing A. auriculiformis only werestarted six months later and harvested at 6, 12 and 18 months; there was no differenceattributable to season as opposed to tree age. In the second experiment, A. auriculiformisand L. diversifolia were grown in four spacing treatments: 1x1, 2x1 , 2x2 , and4 x 0.5 m. Harvest at 24 months showed no differences in leaf area or woody biomassallometric equations among spacings for either of these species. Combined acrossboth experiments, the exponents of the leaf area allometric equations did not differfrom 2.0,supporting the "pipe model"theory of physiological regulation of leaf area.The exponents of the biomass allometrics were significantly different from 2.0(generally near 3.0), implying that sampling and mensuration methods based ondiameter squared are biased.

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