油松人工林不同大小林隙环境因子差异性比较

Comparison of environmental factors differences in gaps with different size of Pinus tabulaeformis plantation

【目的】油松Pinus tabulaeformis是我国北方地区主要造林树种。旨在阐明油松人工林抚育间伐24 a后形成的不同等级林隙间环境因子的差异,探讨林隙的形成对环境因子的影响以及环境因子间的相关关系。【方法】在油松人工纯林选择4种等级的林隙,即林隙直径和冠层平均树高(即林分平均高)之比分别为L-Ⅰ(0.75 H)、L-Ⅱ(1.00 H)和L-Ⅲ(1.25 H)(H为冠层均高)和对照(CK,林冠下),测量了生长旺季的环境因子(光合有效辐射、空气温度、空气湿度、土壤温度和土壤湿度),在此基础上,分析了不同林隙等级间和林隙内不同区域的环境因子的差异性以及环境因子间的相关关系。【结果】1)不同等级林隙间光合有效辐射和土壤温度均达到了显著差异(P <0.05),最大差值分别达到了167.94μmol/m^2s和0.7℃,且随着林隙面积的增大而增大。2)3个面积等级的不同区域间光合有效辐射均表现出了显著的差异,土壤温度仅在L-Ⅱ面积等级林隙中达到了显著差异(P <0.05),在林隙中心区域光合有效辐射和土壤温度具有最大值。3)除了L-Ⅲ面积林隙等级外,其余的林隙等级和对照内光合有效辐射与土壤温度之间均有显著的正相关性(P <0.05)。【结论】在油松人工林内,抚育间伐24 a后,间伐产生的不同等级林隙和林隙区域会对光合有效辐射与土壤温度产生显著影响,对其他环境因子的影响不大。

【Objective】Chinese pine(Pinus tabulaeformis) is the main afforestation tree species in northern China, in order to elucidate the differences of the environment factor between different size forest gap formed by tending and thinning on Chinese pine plantation and to explore the influence of the formation of the gap on environmental factor and the correlation between environmental factors.【Method】We selected four rank forest gap based on the ratio of diameter of forest gap to the mean height(H) of the canopy trees, L-Ⅰ(0.75 H)、L-Ⅱ(1.00 H)、L-Ⅲ(1.25 H) andclosed canopy reference plots(CK), the regeneration status of Chinese pine was investigated and the environmental factors(photosynthetically active radiation, air temperature, air humidity, soil temperature and soil humidity) were measured during the growth peak season in every plot. On this basis, we then analyzed the differences of environmental factors between different forest gap grades and different sections within the forest gap, and the correlation between environmental factors. 【Result】1) That photosynthetic active radiation and soil temperature reached significant difference indifferent forest gap grades(P < 0.05), and increases with the increase of forest gap sizes. The maximum of photosynthetic active radiation and soil temperature respectively was 167.94 mmol/m^2 s and 0.7 ℃. 2) The photosynthetic active radiation showed significant differences between different areas among all rank forest gaps and the soil temperature reached significant difference only in L-Ⅱ level gaps(P <0.05), the maximum of photosynthetic active radiation and soil temperature always located in the center of forest gap. 3) In addition to L-Ⅲ gaps, there was a significant positive correlation between soil temperature and photosynthetic active radiation(P < 0.05). 【Conclusion】Forest gaps of different sizes produced by thinning in Chinese pine plantation have significant influence on photosynthetic active radiation and soil temperature, but little influence on other environmental factors.