The wind-break potency & roughness of the trunk shelterbelt of Casuarina equisetifolia and engineering barrier in each season by the way of line transect method in Changjiang’ao wind-gap of Pingtan Island in Fujian Province was evaluated.The windproof potency index & measurable factors were conducted correlation analysis. Result shows that:①the air speed of trunk shelterbelt gradual decline with the distance from the windward side in-crease in each season,but the wind-break potency & roughness show opposite tendency;②within the range of 0-150 m in coastal trunk shelterbelt,it totally existed three,five & four wind gradient (P<0.05)with significant difference,and three,four and four windspeed reduction efficiency gradient(P<0.05)with significant difference, and four roughness gradient (P<0.05)with significant differences respectively in each season at the height of 2 m, 1.5 m and 0.5 m;③the engineering barrier existed quite obvious wind-break potency and roughness in each season;④the wind-break potency,roughness,tree height &DBH had a significant correlation with each other(P<0.01)in the whole year except the winter;the wind speed have negative correlation with the wind-break potency,roughness, tree height & DBH;R2≥|-0.680|(the coefficient of determination)and the wind-break potency,roughness, height of tree and DBH showed positive correlation with each other,the coefficient of determination is R2≥0.490;⑤it should build 150-m-wide trunk shelterbelt to effectively reduce the wind speed in the coast depending on the present operating mode for Casuarina equisetifolia.%采用样线法,对福建平潭长江澳木麻黄基干林带及工程沙障各季度防风效能和粗糙度进行评价,并将防风效能指标与测树因子进行相关性分析。结果显示：(1)基干林内各季度各梯度林带随着距迎风面距离的增加,风速逐渐下降,防风效能和粗糙度逐渐上升；(2)各季度基干林内0~150 m范围,在2 m、1.5 m 和0.5 m 高度处,总体上分别存在3个、5个和4个差异显著(P<0.05)的风速梯度,3个、4个和4个差异显著(P<0.05)的防风效能梯度,4个差异显著(P<0.05)的粗糙度梯度；(3)工程沙障各季度均存在较明显的防风效能和粗糙度；(4)除了冬季防风效能、粗糙度、树高和胸径相关性不显著外,其他各季度各指标间均存在极显著的相关性(P<0.01),风速与防风效能、粗糙度、树高和胸径呈负相关,可决系数R2≥|-0.680|,防风效能、粗糙度、树高和胸径间呈正相关,可决系数R2≥0.490；(5)根据目前木麻黄基干林带的经营方式,至少应营建150 m宽的基干林带,才能有效降低海岸风口风速。
展开▼
