| Forest ecosystem is the main part of the terrestrial ecosystem, in which core researches are launched on the temporal and spatial distribution of water, delivery and conversion of water, and hydrological cycle mechanism. The paper is based on Research on Deciduouse Forest Ecosystem at Genhe of the Greater Xingan Mountains, Inner Mongolia, the 9th Five-Year-Plan and the 10th Five-Year-Plan major project directed by the State Forestry Administration, and the Greater Xingan Mountains Larix gmelini Ecosystem research station. Typical watersheds were chosen at the northern, middle parts of the Greater Xingan Mountains to function as research sites. The paper mainly applies position research, assisted with the combination of typical regions' statistic analysis and model simulation. Atmosphere, plant and soil subsystems are three major research spaces, where the main research is oriented by the movement routes of precipitation, evaporation and runoff at the Greater Xingan Mountains. According to Larix gmelini Ecosystem' function in delivering and converting water, the following tasks are to be finished: (1) Research the laws of regulating and conserving precipitation by Larix gmelini forest ecosystem;(2) Research evapotranspiration and energy conversion laws of Larix gmelini forest, and forest evapotranspiration distribution model; (3) Define random laws of river runoff at the typical watersheds of the Greater Xingan Mountains, and artificially arrange the hydrological series; (5) Analyze impacts of the forest coverage rate of the Greater Xingan Mountains, forest fires, and forest felling, on river runoff, and make simulation model; (6) Analyze water chemical characteristics of Larix gmelini forest at cold temperate belt; (7) Research climatic changes' effect on frozen soil water and its ecological responses. The paper is aimed to disclose the relations between forest and hydrological functions at the Greater Xingan Mountains, eco-hydrological functions of Larix gmelini Ecosystem at the Greater Xingan Mountains, and mutually controlling mechanism of frozen soil and forest at the special forest environment of the Greater Xingan Mountains.These researches are conducive to the understanding of water movement processand mechanism of Larix gmelini Ecosystem at the Greater Xingan Mountains, the accurate appraisal of functions of forest at the Greater Xingan Mountains, the supply of theoretical proofs for natural forests protection project at the Greater Xingan Mountains, as well as technological supports for local forest management. Main research results:(1) Results indicate that the average crown interception storage rate is 16% to 19% of Larix gmelini Ecosystem at the Greater Xingan Mountains, which decreases with rainfall in creasing. Rainfall inside forest accounts for about 81% of rainfall outside forest. Moreover, there is an obvious linear correlation between them, which can be used to make simulation model or forecast rainfall inside forest. Stem runoff volume only accounts for 3.26% of the total rainfall.(2) Heat consumed by virgin Larix gmelini forest's transpiration and soil evaporation accounts for 82.3% of net radiation, exchanged heat by turbulence accounts for 12.84%, and retained heat by soil 3.53%. In the diurnal process of heat balance, latent heat flux approximately accounts for 64% of net radiation in forest function layer, sensor heat flux 25%, soil heat flux 9.9%. Forest land evaporation and forest transpiration at the southern Greater Xingan Mountains accounts for 60.57% of forest evapotranspiration. Moreover, evaporated interception accounts for 34.43% of forest evapotranspiration, and accounts for 29% of rainfall.(3) Situated at the upper reach of Genhe river, the northern Greater Xingan Mountains,/Wulikuma hydrological station has an steady, random annual runoff sequence, without any tendency and periodic. Annual and seasonal cycle models can produce good artificial runoff sequence.(4) With forest coverage rate increasing, river runoff obviously decreases. At the wa...
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