Study On Forest Structure And Soil & Water Conservation Function Of Shelterbelt Around LiaoDongDahuofang Reservoir

In this study,4 different kinds of typical shelterbelts such as Pinus tabulaeformis,Robinia pseudoacacia,Larch forest and coniferous&coniferous and broad-leaved mixed forest were selected as research objects,and the forest structure and soil&water conservation functions of 4 different forest stands were compared and analyzed.Subsequently,according to the relationship between the forest structure and the soil&water conservation function indices,the forest structure adjustment and optimization measures&plans based on the soil&water conservation function oriented type of the 4 forest stands were proposed,in order to provide a theoretical reference basis for improving the soil&water conservation function of typical shelterbelt through the adjustment of forest structure afterwards among the study area.The main findings are as follows:(1)Non-spatial structure:The DBH,crown width and tree height distribution of Pinus tabulaeformis forest all showed a single peak normal distribution;the DBH,crown width and tree height distribution of Robinia pseudoacacia forest showed a double peak distribution form;the DBH,crown width and tree height distribution of coniferous and broad-leaved mixed forest generally showed an"inverted J" type distribution state,and the forest trees in the stands showed a trend of decreasing from small-diameter small-height trees to large-diameter trees.(2)Spatial structure:The distribution pattern of Pinus tabulaeformis forests was randomly distributed,and the growth trend of forest stands was moderate and inferior;the distribution pattern of Robinia pseudoacacia forest stands was in a cluster-like distribution,the growth of forest showed a moderate state;the distribution pattern of the stand of the Larch forest was randomly distributed,and the growth trend of the forest was moderate to inferior;the distribution of forests in coniferous and broad-leaved mixed forests was mainly distributed randomly,the size ratio of coniferous and broad-leaved forests was small,and the growth was sub-dominant to moderate.There was a close positive correlation between the stand density and the forest competition indices.In general,the forest competition indices increased with the increase of forest density.That is to say,when the forest was sparse,the competition indices of the forests were small.(3)Soil&water conservation function:4 different forest stands had the functions of nourishing water source and conserving soil to various degrees.However,the effects of different functions under various forests were different.The soil&water conservation functions of the 4 forests were represented by their progress values.The smaller the progress value was,the better the function would be.The order of soil&water protection functions of the 4 forests was:Coniferous and broad-leaved mixed forest(0.436)>Robinia pseudoacacia(0.51 6)>Larch forest(0.6)>Pinus tabulaeformis(0.79).(4)Optimization of stand structure:Through correlation analysis of forest stand structure indices and soil&water conservation function indices in the study area,it was found that:The stand size of the stand structure and the maximum water holding capacity of the litter under the forest were significantly positively correlated(0.5 75*).There was a significant negative correlation between the height of forest tree and the capillary porosity of the soil under the forest(-0.768*).The stand angle scale was significantly negatively correlated with the soil bulk density under the forest stand(-0.678*),and was significantly positively correlated with soil maximum water holding capacity(0.547**).The size ratio of stands was significantly positively correlated with the soil bulk density under the stand(0.523*),and was significantly positively correlated with the soil organic matter content(-0.697*)and the soil steady rate(-0.609*).In addition to the soil bulk density,soil water holding capacity,pH and steady osmosis rate,the mixed degree showed significant correlation with other soil&water conservation function indices,indicating that the higher the degree of mixed forest was,the better the soil&water conservation function of the forests would be.The above research conclusions had positive reference significance for improving the forest stand structure of the study area and further improving the soil&water conservation function of the forest typical stand in the study area.