[Calculation method of ecological water requirement for forestland and its application to Huang-Huai-Hai region].

The evapotranspiration and soil moisture content of forestland were studied in relation to free growth. It was found that when the soil moisture content was about 45～100 % of field capacity and the actual evapotranspiration came up to 60～100 % of potential evapotranspiration,the growth of trees could be sustained. On the basis of our research,the grading standard and calculation method of ecological water requirement of forestland were established. Moreover,the ecological water requirement for forestland in Huang Huai Hai area was estimated by GIS technology,and its ecological water shortage was compared to its current water consumption. The results indicated of that the annual ecological water requirement of forestland in Huang Huai Hai region was 25.6～45.8 billion m 3,and its current water consumption was approximately 2.8 billion m 3 below the minimum of ecological water requirement,and 8.4 billion m 3 below the optimal ecological water requirement.