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关于林带走向与防风效果的关系,国内外有过大量的报道,传统的说法是:当林带与风向成垂直时,防风效果最好,所以主林带应与当地主害风方向相垂直.南京林学院等单位,1960年在对苏北沿海农田防护林防护效果的研究中指出:在林带背风面15倍树高处,当林带与风向垂直时,降低风速17.40%;当林带与风向成67.5度交角时,降低风速14.06%;当林带与风向成45度交角时,仅降低风速9.55%;观测林带宽10米,由5行槐树、4行楝树、4行紫穗槐组成,透风系数为0.41.那么,对于透风系数不相同的林带,在和风向成不同交角时,是否都具有上述的规律呢?我们通过近两年的观测,感到不宜
With regard to the relationship between the forest belt and the windbreak effect, there are a lot of reports at home and abroad. The traditional view is that when the forest belt is perpendicular to the wind direction, the windbreak effect is the best, so the main forest belt should be perpendicular to the direction of the local main wind. Institute and other units, in 1960 on the North Jiangsu coast farmland shelterbelts protective effect study pointed out: 15 times in the forest leeward tree height, when the vertical with the wind direction, reducing wind speed 17.40%; when the forest and the wind into a 67.5 degree angle , The wind speed decreased by 14.06%; when the forest belts crossed with the wind direction by 45 degrees, only the wind speed was reduced by 9.55%; the observed forest width was 10 meters and consisted of 5 locust trees, 4 neem trees and 4 rows of Amorpha fruticosa, 0.41. So, for the forest with different air permeability coefficient, the wind direction into a different angle, whether all have the above rules? We through the past two years of observation, it is not appropriate