Static Water-holding Capacity Of Water Conservation Forest In Upper Reach Of Ashi River Basin

Considering the increasing water demand of Harbin city and a remarkable importance of ecological function of water conservation forest, the forest ecosystem of upper reach of Ashi river basin should be recognized from a strategic level for water resource safety, located scientifically, utilized reasonably, and constructed in priority for the purpose of forest ecosystem environmental protection and sustainable development. An investigation on water-holding capacity was conducted for the forest ecological construction in upper reach of Ashi river basin from June to August in 2007, after cellecting the refernces about forest hydrology and the mechanism of water conservation forest at domestic and oversea. Different types of forest stands in two ditchs (Guangming and Yuchi) in upper reach of Ashi river basin, selected as the experimental area, were investigated by using forest image conbinated with field-investigation. 10 plots (20m×20m) with typical vegetigation feature were set in the experimental area. The characteristics of height, diameter, ages and vegetation types of stands were investigated, and structural characteristics of the two ditchs was also confirmed. It was foucsed on the three aspects of forest plant, litters and forest soils to investigate air drop, throughfall, stem flows, herbage layer, litters, and soil hydrology by using normal investigations and measurements. Static water-holding capacity in small river basins was analyzed by combination of quantification and quantity. Results showed that water-holding capacity of water conservation forest in yuchi ditch, dominated by natural second growth forest was significantly stronger than that in guangming ditch dominated by planted forest. Comparing the static water-holding capacity among different stands for planted forest, pine forest was the strongest, followed by larch and pinus sylvestris; for natural second growth forest, water-holding capacity of Mongolian oak was stronger than mixed confir-broad forest, and the sequences of others shaw from high to low was Fraxinus mandshurica, broad leaved community and Pinus sylvestris plantation var.mongolica, Korean pine plantation.The above difference was mainly caused by different stand types, thus a reasonable allocation of forest stands was the optimum choice for improving the ecology service function of water conservation forest.