Russo Sabrina E, Wiser Susan K, Coomes David A
Conservation and Community Ecology Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK.
Ecol Lett. 2007 Oct;10(10):889-901. doi: 10.1111/j.1461-0248.2007.01079.x.
The Metabolic Ecology Model predicts that tree diameter (D) growth (dD/dt) scales with D(1/3). Using data on diameter growth and height-diameter relationships for 56 and 40 woody species, respectively, from forests throughout New Zealand, we tested one prediction and two assumptions of this model: (i) the exponent of the growth-diameter scaling relationship equals 1/3 and is invariant among species and growth forms, (ii) small and large individuals are invariant in their exponents and (iii) tree height scales with D(2/3). We found virtually no support for any prediction or assumption: growth-diameter scaling exponents varied substantially among species and growth forms, correlated positively with species' maximum height, and shifted significantly with increasing individual size. Tree height did not scale invariantly with diameter. Based on a quantitative test, violation of these assumptions alone could not explain the model's poor fit to our data, possibly reflecting multiple, unsound assumptions, as well as unaccounted-for variation that should be incorporated.
代谢生态学模型预测，树木直径（D）的生长速率（dD/dt）与D的1/3次方成正比。我们分别利用新西兰各地森林中56种和40种木本植物的直径生长数据以及树高与直径的关系数据，对该模型的一项预测和两项假设进行了检验：（i）生长-直径比例关系的指数等于1/3，且在物种和生长形式之间不变；（ii）大小个体的指数不变；（iii）树高与D的2/3次方成正比。我们几乎没有找到对任何预测或假设的支持：生长-直径比例指数在物种和生长形式之间差异很大，与物种的最大高度呈正相关，并且随着个体大小的增加而显著变化。树高与直径并非固定比例关系。基于定量测试，仅违反这些假设并不能解释该模型与我们数据的拟合不佳，这可能是由于存在多个不合理的假设以及应纳入但未考虑的变异。
