Abstract
Weller's allometric model assumes that the allometric relationships of mean area occupied by a tree , i.e., the reciprocal of population density , , mean tree height , and mean aboveground mass density to mean aboveground mass hold. Using the model, the self-thinning line of overcrowded Kandelia obovata stands in Okinawa, Japan, was studied over 8 years. Mean tree height increased with increasing . The values of the allometric constant and the multiplying factor are 0.3857 and 2.157 m kg(-theta), respectively. The allometric constant and the multiplying factor are -0.01673 and 2.685 m(-3) kg(1-I '), respectively. The value was not significantly different from zero, showing that remains constant regardless of any increase in . The average of , i.e., biomass density , was 2.641 +/- A 0.022 kg m(-3), which was considerably higher than 1.3-1.5 kg m(-3) of most terrestrial forests. The self-thinning exponent and the multiplying factor were estimated to be 1.585 and 16.18 kg m(-2 alpha), respectively. The estimators and are dependent on each other. Therefore, the observed value of cannot be used for the test of the hypothesis that the expectation of the estimator equals 1/3, i.e., , or 1/4, i.e., . The value was 0.6310, which is the same as the reciprocal of the self-thinning exponent of 1.585, and was not significantly different from 2/3 (t = 1.860, df = 191, p = 0.06429), i.e., . Thus the self-thinning exponent is not significantly different from 3/2 based on the simple geometric model. On the other hand, the self-thinning exponent was significantly different from 3/4 (t = 6.213, df = 191, p = 3.182 x 10(-9)), i.e., . Therefore, the self-thinning exponent is significantly different from 4/3 based on the metabolic model.