阿拉尔垦区新疆杨农田防护林防风效果研究

Study on the windproof effect of aPopulus alba L.var pyramidalis farmlandshelterbelt in Alar Reclamation Area

以阿拉尔市新疆杨农田防护林为研究对象,通过林业调查和野外风速测定,依据疏透度将新疆杨防护林的林带结构划分为通风型、疏透型、稀疏型3种结构类型,并采用隶属函数法对比分析各林带防风效果。结果表明:1)水平方向上,防风效能随防护距离的增加呈下降趋势。3种结构类型防护林的防风效能表现为稀疏型>疏透型>通风型。2)防风效能与树高、胸径、林带行数、冠幅呈正相关,与密度、疏透度呈负相关。3)8条林带综合隶属函数值在0.097~0.770之间,依次表现为林带Ⅲ>林带Ⅴ>林带Ⅳ>林带Ⅶ>林带Ⅷ>林带Ⅱ>林带Ⅵ>林带Ⅰ。其中,林带Ⅲ、林带Ⅴ为稀疏型,隶属函数值在0.50以上,综合防护效益表现较好。

Taking the farmland shelterbelt of Populus alba L.var pyramidalis in Alar city as the research object,through forestry investigation and field wind speed measurement,the structure of Populus alba L.var pyramidalis shelter belt was divided into three types:ventilation type,permeability type and sparsity type according to the porosity,and the windproof effect of each forest belt was compared and analyzed by membership function method.The results showed that:1)In the horizontal direction,the windbreak efficiency decreased with the increase of windbreak distance.The wind-proof efficacy of the three structure types of shelter belts was sparsity type>permeability type>ventilation type.2)The windbreak efficacy was positively correlated with tree height,breast height diameter,number of tree rows and crown width,and negatively correlated with density and porosity.3)The comprehensive membership function values of 8 forest belts ranged from 0.097 to 0.770,which were in the order of shelterbeltⅢ>shelterbeltⅤ>shelterbeltⅣ>shelterbeltⅦ>shelterbeltⅧ>shelterbeltⅡ>shelterbeltⅥ>shelterbeltⅠ.The numberⅢandⅤshelterbelts are sparse type,the membership function value is above 0.50,and the comprehensive protection benefit was better.