【摘要】 本文讨论了科尔沁沙地疏林草场的气象效应和防风效应的风洞模拟实验,结果表明,林内风速随林分郁闭度的增加而减少;林地的粗糙度随郁闭度的增加而增大,相当于林分高度的1/20—1/70。疏林草场与旷野相比,蒸发减少12—20％,蒸腾增加7.3％。更多还原

【Abstract】 An increase in the closeness of the artificial grazing forest from 1.1-2.0% to 9.6% resulted in a decrease in the relative wind speed from 88% to 62%. The closeness of the natural grazing forest in 19% and 59% with mean heights of 7m and 9m, respectively, leads to the relative wind speeds of 65% and 22%, respectively. The results from modeling experiment of grazing forest in a wind tunnel indicate that if the closeness degrees of the grazing forest model are 3 %, 6 % and 25%, the relative wind speed will be 64%, 60% and 45%, respectively.This means that the wind speed within the forest will be reduced as the closeness of the forest increases. In addition, an increase in the closeness of forest will increase the roughness of woodland which is from about 1/20 to 1/70 of the height of forest stand. In the grazing forest, as compared with open wildness, it was found that the evaporation was reduced by 12-20% while the transpiration was being increased by 7.3%.更多还原