The Influence Of Water Conservation Forest Structure On The Function And Forest Health Assessment In Eastern Liaoning

Forest ecosystems,especially water conservation forests,play an important role in water conservation,and scholars have carried out many related studies and discussions,but the mechanism of the impact of main fore in st structure on water conservation in eastern Liaoning is not clear.Taking the typical water conservation forest of Dahuofang Reservoir in Liaodong as an object,this paper studied the structural characteristics of water conservation forest and the characteristics of water conservation function,and used path analysis to quantitatively analyze the mechanism of the effect of forest structure on the function of conservation water.Then this paper improved the health evaluation index system of water conservation forest,and carried out function-oriented water conservation forest health assessment,and it hopes to provide theoretical guidance for the management and management of water conservation forests,and promotes forest health and sustainable development.The main research results are as follows:(1)Analysis of forest structure characteristics of 5 typical water conservation forests(Pinus tabulaeformis,Larix gmelinii,Pinus koraiensis,Robinia pseudoacacia,coniferous and broadleaved mixed forest)in the water conservation area of Dahuofang Reservoir.The results showed that : the number of three coniferous pure forests showed a normal distribution trend of increasing first and then decreasing with the DBH,tree height and crown area..However,the three indicators showed a bimodal distribution trend of decreasing first and then increasing then decreasing in the Robinia pseudoacacia.The difference is that in coniferous and broad-leaved mixed forests,the three indicators are generally inverted “J” type distribution,and are smaller than the other four pure forests.The study of understory herb structure revealed that there were 89 species of 78 genera and 39 families in herbaceous species;Herbal biomass was negatively correlated with the four diversity indexes(P<0.05).In the later stages of Larix gmelinii forest development,the herb richness index(R)species number was basically stable,and the diversity index(H)decreased as the forest age increased.The spatial distribution pattern of the three coniferous forests is in a random distribution state,the growth trend is in a moderate to inferior state,and the forest tree competition index is between 1.14 and 1.93.Both are worse than Robinia pseudoacacia and the coniferous and broad-leaved mixed forest.(2)The order of the average canopy interception rates of the five forest stands was: Robinia pseudoacacia > coniferous and broad-leaved mixed forest> Pinus koraiensis > Larix gmelinii> Pinus tabulaeformis,and the variation range is between 15.46%—27.43%.The maximum water holding capacity of litter is the largest in coniferous and broad-leaved mixed forest,and the variation range is between 13.61-27.21t/hm2;there is a significant logarithmic function relationship between the maximum water holding capacity and the soaking time: Q = alnt + b(R2> 0.86).The initial soil infiltration rate of different forests is quite different,and the steady infiltration rate is the largest in the coniferous and broad-leaved mixed forest.(3)Quantitative and comprehensive analysis of forest water conservation function using comprehensive assessment method,and the results show that: the comprehensive score of water conservation function of different forests is between0.56—1.01,and the order of magnitude is: coniferous and broad-leaved mixed forest> Robinia pseudoacacia> Larix gmelinii> Pinus koraiensis> Pinus tabulaeformis.(4)Using multiple regression analysis and path analysis to explore the relationship between stand structure and water conservation function,it was found that the stand structure has a greater influence on the water conservation function.Among them,forest density,stand canopy closure,forest tree competition index and herbaceous species diversity have a greater impact,and the forest water conservation capacity can be improved by improving the forest structure.To construct a coupling model of water conservation forest structure and water conservation function of Dahuofang Reservoir,and calculate its standard deviation(RSD)to verify the credibility of the model.The results show that the model has high credibility.(5)In the forest health assessment,based on the conventional health assessment indicators,the functional indicators of water conservation are added to reflect the functional orientation of the forest health assessment,and the four criteria layers of "system vitality-organizational structuresystem resilience-water conservation" are determined,and 19 indicators were selected to build an evaluation indicator system.The comprehensive index method is used to quantify the health values of different forests.The results show that the water conservation forest in Dahuofang Reservoir is in three states: healthy,sub-healthy and unhealthy;the average health index of the plot is 5.86,which is in a sub-health state;forests with different forests The health index values are ranked as follows: coniferous and broad-leaved mixed forest> Robinia pseudoacacia > Larix gmelinii > Pinus koraiensis > Pinus tabulaeformist.For forests with lower health values,forest management and transformation need to be further strengthened.