黄土丘陵区油松人工林水分生态效益研究

Study on Water Ecological Benefits of Artificial Chinese Pine Stands in Loess Hilly Region

林内透过降水量占同期林外降水的 78.3% ,林冠截留量占 19% ,树干径流量占 2 .7% ,枯枝落叶层截留量占 9.5 %。林分密度对林内透过降水量影响很大 ,二者呈负相关关系。日平均相对湿度林外大于林内 ;日平均相对湿度垂直变化由大到小为冠层中部 >林内 1.5 m处 >林冠表层 ;坡向和坡位对相对湿度变化过程有显著影响。油松林地 3～ 10月的平均含水量为 11.4 6 % ,约相当于田间持水量的 5 0 % ;采伐 4年后的迹地的土壤水分恢复能力较强 。

The results of water ecological benefits of artificial Chinese pine stands in loess hilly region showed that precipitation under the canopies accounts for 78.3% of total in the open field,and similarly,the interception of the canopy is 19%,the stemflow is 2.7%,the interception of litter is 9.5%.The density of the stands has great influences on the precipitation under the canopies with a negative correlation. The daily average relative humidity in the stands is lower than that in field.The sequence of daily vertical variation of average relative humidity from large to little is the middle of the canopies>1.5 m high in the stands>the canopy surface.The direction and location on the slope have remarkable influences on the daily variational process of relative humidity in the stands.The average soil moisture during the period from March to October is 11.46%,which equals to 50% of field moisture capacity.The field which trees had been cut 4 years has better recovery capability for soil moisture and its monthly average soil moilture is higher than that in the stands.