Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forestry, Beijing Forestry University, No. 35, Qinghua East Road, Beijing, 100083, P. R. China.
National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, No. 35, Qinghua East Road, Beijing, 100083, P. R. China.
Sci Rep. 2017 Nov 6;7(1):14568. doi: 10.1038/s41598-017-15322-8.
Understanding the influence of gaps in promoting canopy recruitment will help to maintain structural stability and achieve continuous forest cover. We established three control plots and experimental plots with three replications each (gap sizes L-I, L-II, L-III, and L-IV) in a Chinese pine (Pinus tabulaeformis Carr.) plantation to test the short-term effects of gap size on the age distribution, density and growth, and annual height and ground diameter growth for regeneration established before (REBG) and after (REAG) gap creation. Age distribution exhibited an approximately normal distribution, with the numbers of REBG and REAG decreasing and increasing, respectively, as the age increased. Although there was no difference in density among gap size classes, regeneration growth positively responded to gap size, with maximum values observed in class L-III. Annual average height growth after (AAH-A) gap creation was significantly greater than that before (AAH-B) gap creation for REBG among gap sizes, suggesting that gaps promote the rapid growth of regeneration. However, the responses of height and ground diameter growth in REBG to gap size were not immediate and exhibited a response delay of 2-4 years. Similarly, for the height and ground diameter growth of REAG, significant differences were first observed within years 2-4 after germination in the same growing season for all gap size classes.
了解促进林冠更新的林窗大小的影响，有助于维持结构稳定性和实现连续的森林覆盖。我们在油松（Pinus tabulaeformis Carr.）人工林设立了三个对照样地和三个重复的实验样地（林窗大小 L-I、L-II、L-III 和 L-IV），以检验林窗大小对林窗形成前后（REBG 和 REAG）更新苗年龄分布、密度和生长、以及年高和地径生长的短期影响。年龄分布呈近似正态分布，随着年龄的增加，REBG 和 REAG 的数量分别减少和增加。虽然不同林窗大小之间的密度没有差异，但更新苗的生长对林窗大小呈正响应，在林窗大小 L-III 中观察到最大值。与林窗形成前（AAH-B）相比，REBG 在林窗形成后（AAH-A）的年平均高度生长显著增加，表明林窗促进了更新苗的快速生长。然而，REBG 的高度和地径生长对林窗大小的响应不是即时的，表现出 2-4 年的响应延迟。同样，对于 REAG 的高度和地径生长，在同一生长季节，所有林窗大小类别的萌蘖在第 2-4 年开始才首次出现显著差异。
