Microclimate regimes following gap formation in a montane secondary forest of eastern Liaoning Province, China

以便在东北中国在一个第二等的森林里在物理环境上改进华盖洞 / 差距的角色的理解，案例研究被进行在里面；在一个山区的第二等的森林里的小不规则的差距附近。第二等的森林，大约 50 年以前被人严重地扰乱，被 Quercus 蒙古人集成通信适配器统治；Fraxinus rhynchophyllaan。在光合的光子流动密度(PPFD ) 的时间的变化，在在地面上面的 10 厘米的气温(T A ) ，土壤温度(T S ) ；土壤水分含量(SWC ) 在最高层(0 15 厘米) ；自从小差距的形成，亚层(15 30 厘米) 在第二年以后从 5 月被测量到 9 月(到看台高度的差距直径的比率是不到 0.5 ) 在 2006 分别地。结果显示 PPFD 的最高的价值发生在差距的北边，特别地在在 5 月的生长期的开始。在阳光充足的天， PPFD 的最高的价值在阴暗的天比那早出现了。最大；T A 的平均值在差距的北部分是更高的，；T A 的最小的价值在差距的南部的边。土壤温度从 1 ～ 8 ° C 与范围在差距显然变化了。T S 的最大的价值发生在差距的北部分，它显著地与 T A 的最大的价值被相关(R = 0.735， P【0.05 ) 。SWC 是更高的在最高层(0 15 厘米) 比那在里面亚层(15 30 厘米) ，而是他们的差别不是重要的(p】0.05 ) ，它可能被归因于小差距尺寸；效果未葬植被。从这些结果，在学习区域的 PPFD 的最大值在差距的北部分发生了，它与结果在北方半球观察了一致，但是出现时间与纬度的差别变化了。空气的最高的价值；因为他们被放射影响，土壤温度也发生在差距的北部分。然而，在 7 月的温度的变化由于差距尺寸的影响与另外的月不同。并且土壤水分含量的价值不在在湿季节的差距更高是任何一个也不在干旱期降低，它可能被差距尺寸影响；差距定位了的地形学。光的变化，土壤；气温，；在这小不规则的差距的土壤潮湿可能与效果有关微地点，它影响植物种类的新生。

In order to improve the understanding of the role of a canopy opening/gap on the physical environments in a secondary forest in Northeastern China, a case study was conducted in and around a small irregular gap in a montane secondary forest. The secondary forest, which was severely disturbed by human beings about 50 years ago, was dominated by Quercus mongolica and Fraxinus rhynchophyllaan. Temporal variation in photosynthetic photon flux density （PPFD）, air temperature （TA） at 10 cm above the ground, soil temperature （Ts） and soil water content （SWC） at top-layer （0-15 cm） and sub-layer （15-30 cm） were measured from May to September after the second year since the formation of the small gap （the ratios of gap diameter to stand height were less than 0.5） in 2006 respectively. Results indicated that the highest value of PPFD occurred at the northern edge of the gap, particularly at the beginning of the growing season in May. On sunny days, the highest value of PPFD appeared earlier than that on overcast days. Maximum and mean values of TAwere higher in the northern part of the gap, and the minimum values of TAwere at the southern edge of the gap. Soil temperature varied obviously in the gap with the range from 1 to 8 ℃. Maximum values of Ts occurred at the northern part of the gap, which was significantly correlated with the maximum values of TA （R = 0.735, P〈0.05）. SWC was higher in the top-layer （0-15 cm） than that in sub-layer （15-30 cm）, but the difference of them was not significant （p〉0.05）, which might be attributed to the small gap size and the effects of aboveground vegetations. From these results, the maximum of PPFD in the study area occurred at the northern part of the gap, which was consistent with the results observed in north hemisphere, but the occurrence time varied with the differences of the latitudes. The highest values of air and soil temperatures also occurred in the northern part of the gap because they were affected by the radiation. However, the variation of temperature in July was different from other months due to the influence of gap size. And the values of soil water content were neither higher in the gap in the wet season nor lower in the dry season, which might be affected by the gap size and topography the gap located. The variations of light, soil and air temperatures, and soil moisture in this small irregular gap might be related to the effects of the micro-site, which affects the regeneration of plant species.