西双版纳干季人工林林窗边缘增温效应初步分析

Initial Study on the Edge Effect of Temperature Increasing at the Artificial Forest Gap in Dry Season in Xishuangbanna

以林窗北缘为中心 ,研究了西双版纳地区橡胶林林窗及周边N—S样带上温度水平梯度分布及林缘增温效应 .结果表明 :1)干季落叶期林窗林缘的增温效应明显、热力状况复杂 ,主要表现为林缘热力效应因时因地而变 ;2 )林缘增温效应并不局限于林缘本身 ,同时牵动周边温度上升 ,但这种增温效应随深入林内距离的增加呈指数递减之势 ,而且增温效应影响范围随空间和时间而变 ,其中北侧林缘 12～ 14时影响深度最远 ,最甚时可到林内距北侧林缘 16m处 ;3)气 -地温差的局地差异因时而变 ,不同程度地影响和控制着林窗不同介质间的热交换 ,影响林缘的增温效应 .

Taking the north forest edge as a central point, the gradient distribution of temperature along sample line from the interior of forest to the center of gap and the edge effect of temperature increasing are studied in the artificial forest in dry season in Xishuangbanna. The results indicate: 1)When leaves fall in dry season, effect of temperature increasing at the forest edge is significant, thermodynamic condition is distinctive, it mainly shows that thermodynamic effect varies with time and sites. 2) Effect of temperature increasing at the forest edge is not confined to itself , it drives temperature of other sites increasing, but the effect exponentially decays when penetrating the interior of forest, its influence extent may be up to 16 m into forest from the north facing edge during 12～14 h. 3) Spatial variations of the difference between the air and surface temperatures at the forest gap varies with time. It affects and controls heat exchange between different media(air, ground surface) in the forest gap. The results supply a research basis for making the best use of the resource of light and heat and for the sustained production of rubber garden.