Seedling recruitment in artificial gaps

We examined the role of both intermediate-sized gaps and a dense shrub layer on subsequent tree seedling recruitment in a southern Appalachian deciduous forest. We monitored the density of tree seedlings in twelve artificial gaps and adjacent canopy controls under two contrasting understory conditions. Half of the experimental gaps were dominated by the dense, shade-producing shrub, Rhododendron maximum, while the remaining gaps were relatively open. Canopy gaps 20 m in diameter were created by girdling canopy trees, leaving standing dead trees with minimal disturbance to the understory. Density of first-year and first-year seedlings was monitored in transects extending from adjacent undisturbed forest through the experimental gaps.

本研究针对阿巴拉契亚南部落叶阔叶林内的中等规模林隙（gap）与浓密灌丛层，探究二者对后续树木幼苗补充的影响。本研究设置两种差异化林下环境条件，对12个人工林隙（artificial gap）及其邻近的冠层对照样地内的树木幼苗密度进行监测。半数实验林隙被浓密遮阴的灌丛——大花杜鹃（Rhododendron maximum）所占据，剩余林隙则相对开阔。本研究通过环剥冠层树木的方式营造直径20米的冠层林隙，保留枯立木以最大限度减少对林下环境的干扰。研究人员在从邻近未受干扰森林延伸至实验林隙的样线内，对一年生及一年生幼苗的密度实施监测。