Dunn Christopher P, Sharitz Rebecca R
Department of Biology, Ball State University, Muncie, Indiana 47306, USA.
University of Georgia, Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South Carolina 29802, and Botany Department, University of Georgia, Athens, Georgia 30602, USA.
New Phytol. 1990 Jul;115(3):559-565. doi: 10.1111/j.1469-8137.1990.tb00484.x.
Self-thinning was examined in shaded and unshaded populations of Murdannia keisak (Hask.) Hand.-Mazz. (Commelinaceae). Four mathematical descriptions of self-thinning were compared: (1) the traditional - 3/2 thinning rule in which mean plant biomass is regressed on density; (2) principal components regression of mean plant biomass and density; (3) total stand biomass regressed on density, and (4) principal components regression of total stand biomass and density. Most slopes conform to the expected ones; however, confidence intervals reported here and in the literature are wide which may reduce the ecological value of the thinning line per se. In addition, plants grown in full sun form significantly fewer branches than those in shade. This difference in geometry results in differences in mean plant volume, in plant packing, and thus, in different thinning trajectories.
对水竹叶（Murdannia keisak (Hask.) Hand.-Mazz.，鸭跖草科）在遮荫和非遮荫种群中的自疏现象进行了研究。比较了自疏的四种数学描述：（1）传统的-3/2疏伐规则，即平均植物生物量对密度进行回归；（2）平均植物生物量和密度的主成分回归；（3）林分总生物量对密度进行回归；（4）林分总生物量和密度的主成分回归。大多数斜率符合预期；然而，本文及文献报道的置信区间较宽，这可能会降低疏伐线本身的生态价值。此外，在全日照下生长的植物形成的分枝明显少于遮荫条件下的植物。这种几何形状的差异导致平均植物体积、植物排列方式不同，从而产生不同的疏伐轨迹。
