河西走廊中部农田防护林防风效应初探

Preliminary investigation on the Windbreak effect of shelterbelt for protecting farmland in the central Area of Hexi Corridor

单个农田林网的防风度为２８．２％，而大面积连片农田防护林体系的建成，区域性防风效应更加显著。与建设初期相比，张掖、临泽和高台３县（市）的总防风速度为４２．８％，年大风日数降低６８．４％，年沙尘暴日数降低６６．１％

the Windbreak degree of single farmland wind-dreak forest network was 28.2% The percent.the regional windbreak effect on the basis of large and continuous area sand and windbreak system is more obvious effect than Singlefarmland Windbreak forest network. Compareing with the beginning of establishment of shelter forest,the whole windbreak degree of three county of Zhangye Linze Gaotai is 42.8 percent, annual days of fresh gale reduce 68. 4percent, annual days of sand dust storm wind reduce 66. 1 percent.