| The relationship between forest and water is always the focus of ecology, and water conservation function is one of the most important functions of forest. The analytic hierarchy process have been applied to the analysis of the hydrologic functions of forest canopy, litter and soil layers in Nenjiangs source. Based on the study of vegetation disposition of water and soil conservation forests, the optimum structure of 13 forest type in this catchment is established.(1) The forest litter maximum content is 33.40-130.86 t/hm2. Regular as the coniferous forest is greater than the broad-leaved forest. Broad-leaved forests are much smaller than coniferous forest.The relationships between water-holding rate and immersion time of whether semi-decomposed or un-decomposed litter in all different fir forests were significantly fitted by Logarithmic equation.13 kinds of forest litter water-holding capacity in different decomposition layer respectively has significant logarithmic relationship between with soaking time, the coniferous forest litter decomposition degree of different water-losing rate were higher than broad-leaved forest. Through the bibulous rate of saturated time fitting, the forest litter decomposition degrees of water absorption rate are saturated state about 6h.(2) The maximum moisture contents, soil available and soil capillary water holding capacity is 996.95-1656.16t/hm2,78.10-414.23t/hm2 and 918.85-1376.05 t/hm2. regular as the broad-leaved forest is greater than the Coniferous forest.(3) The stemflow of Larix gemelnii, Betula platyphylla, Populus davidiana, and Quercus mongolica outside of the rainfall quadratic function relation in different diameter class. Same diameter at breast height, the stemflow of Betula platyphylla and Populus davidiana, there was no significant difference and they were significantly higher than that of Mongolian Quercus mongolica and Larix gemelnii in different level of rainfall。(4) The throughfall of Larix gemelnii, Betula platyphylla, Populus davidiana, and Quercus mongolica are in power function relationship between the leaf area index, light rain when moderate rain, heavy rain and heavy rain when the relationship of a quadratic function(5) The results show that according to stemflow 1.9-12.4mm and throughfall is 162.4 362.1mm. The stemflow of broad-leaved forest a, throughfall were greater than coniferous forest.(6) The canopy interception rate in addition to Herbages-Betula platyphylla forest was 54.91% higher, broad-leaved forest and broad-leaved mixed forest canopy interception rate was 6.30%-54.91%%, and coniferous forest was 18.81%-42.00%。The canopy interception in addition to Herbages- Betula platyphylla forest was (212.8 mm) higher,, broad-leaved forest canopy interception (18.7-129.7 mm) below the coniferous forest (48.7-164.1 mm). The storm rainfall level instead of rainfall(rainfall>50mm), coniferous forest canopy interception quantity is greater than the broad-leaved forest.(7) The optimal vegetation structure should be 13.3% of Oak-Larix gemelnii forest, 10.65% of Corylus heterophylla-Larix gemelnii forest,9.8% of lespedeza oak forest,9.62% of Rhododendron dauricum-Betula platyphylla forest,9.09% of Grass-Populus davidiana forest, 8.59% of Herbages-Betula platyphylla forest,7.62% of Corylus heterophylla-Betula davurica forest,7.15% of Rhododendron dauricum-Larix gemelnii forest,5.99% of Ledum palustre-betula platyphylla forest,5.61% of Oak-betula forest,4.59% of Rhododendron dauricum-Populus davidiana forest,4.05% of Ledum palustre-Larix gemelnii forest,3.94% of Grass-Larix gemelnii forest, After optimization, the water conservation capacity of the watershed could be improved obviously, with maximum moisture contents and soil available increased by 3.1% and 10.0%... |
PDF Full Text Request