一、研究的方法步骤(一)样地区划河南,防护林带一般是南北向每隔五百米左右设置一条主林带,东西向每隔五百米至一千米设置一条付林带。但张茹集林带设置恰相反:主林带距七、八百米左右,付林带距四、五百米。林带宽度五至三十米不等;付林带只有一行树,宽五米左右;主付林带结合路及排水沟,有二至六行树,宽度可达十至三十米左右。为计算方便:我们设置方形样地,面积为 First, the study methods and steps (a) sample area zoning, shelterbelt generally north-south every five hundred meters to set a main forest belt, east-west to every one hundred meters to one kilometer to set a pay forest belt. However, set Zhang Lin forest set the contrary: the main forest with a distance of seven or eight hundred meters, to pay Lin four, five hundred meters. The width of forest belt ranges from five to thirty meters. There is only one row of trees in the forest belt and about five meters in width. The main forest belt and drainage channel have two to six rows of trees with a width of about ten to thirty meters. For calculation convenience: we set the square plot, the area is