Gap Partitioning Among Maples at Harvard Forest 1986-1989

We measured shoot architecture, photosynthesis, survival and growth by seedlings of three shade-tolerant species of maple (Acer pensylvanicum, A. rubrum, A. saccharum) in an experimental test of the gap partitioning hypothesis. Trees were felled to create a total of six cleared, elliptical canopy gaps of two sizes (8m x 12m, 75m2; 16m x 24m, 300m2). Naturally-established, undamaged, unbranched seedlings (15-30 cm tall, 10-20+ years old) of the three study species (2160 total, 720 per species) were transplanted into five plot locations (center and NW, NE, SW, and SE gap edges) within all six gaps and matching understory sites one year before gap creation. All plots were weeded regularly and spaded annually along the edges to remove above and below-ground competition. Measurements of microclimates and Non-competitive seedling responses were made over one year before and two years following gap release.

本研究针对林隙分异假说（gap partitioning hypothesis）开展实验检验，测定了3种耐荫枫属植物（宾夕法尼亚枫*Acer pensylvanicum*、红枫*Acer rubrum*、糖枫*Acer saccharum*）实生苗的枝条构型、光合特性、存活率及生长动态。研究人员通过伐除林木共营造6个清理完成的椭圆形林隙，分为两种规格：8m×12m（面积75m²）、16m×24m（面积300m²）。在林隙营造前1年，我们将3种研究物种的天然定植、无损伤、无分枝实生苗（株高15~30cm，树龄10~20+年，总计2160株，每个物种720株）移栽至全部6个林隙内的5个样点位置（林隙中心及西北、东北、西南、东南边缘），以及与之匹配的林下对照样地。所有样地均定期开展除草作业，并每年沿样地边缘翻土，以清除地上与地下的种间竞争植株。本研究在林隙营造前1年至营造后2年的周期内，测定了微气候特征以及非竞争条件下实生苗的响应指标。