| In the context of global warming and increasing environmental pollution,forest health is currently a controversial research area,and its importance is increasingly valued by forest workers.Assessment of forest health is conducive to a more comprehensive understanding of the current situation of local forest resources,so as to put forward scientific and rational management countermeasures,enhance the stability and biodiversity of forest ecosystems,and better play to the ecological,social and economic benefits of forests.Baoku River Basin is the main source of water resources of Heiquan Reservoir in Datong County.Heiquan Reservoir is an important source of water resources in Xining City,Qinghai Province.60%of the total water supply in Xining City comes from it.Forest plays an important role in water quality and water level of reservoir by retaining and purifying rainfall.In this study,the main forests in the Baoku River Basin were taken as the research objects.Based on the study of forest structure,site conditions,resistance and productivity,and on the basis of previous scholars,and combined with the current situation of local forest resources,the forest health assessment system of the Baoku River Basin was constructed,and the main forest health was evaluated,and the corresponding forest health management strategy were put forward.The main conclusions are as follows:(1)In this paper,the representative forests of Betula platyphylla forest,Larix principis-rupprechtii forest,Picea crassifolia forest,Populus cathayana forest and Picea crassifolia+Betula platyphylla mixed forest are divided into research objects,According to the principles of scientificity,representativeness,operability and systematicness,and from the four aspects of forest structure,productivity,resistance and site conditions,shrub cover,herb cover,canopy closure,species diversity,age group,natural regeneration,hierarchical structure,stand mixed degree,average tree height,The average diameter of the breast,the amount of accumulation,the annual net growth,the degree of pests,human disturbance,fire risk,soil thickness,sQil porosity,humus thickness,slope,slope direction and other 20 related indicators,The index is divided into quantitative index and qualitative index,respectively,using the difference normalization and rank scoring methods for standardization.(2)The expert consultation method(Delphi method)combined with the analytic hierarchy process(AHP method)is used to analyze the weights of each index.The weights of the index indicators are ranked as follows:forest structure(0.3905)>site condition(0.2761)>productivity(0.1953)>resistance force(0.1381).(3)According to the forest health assessment model,the forest health index of the Baoku River Basin is 0.56,which is generally in a healthy state.Among all the surveyed plots,the number of health status plots is the highest,with 19 plots,accounting for 63.3%of the total sample plots.There is 1 good healthy sample plot(3.3%)and 10 sub-healthy sample plots(33.3%),and 0 plot in unhealthy and high-quality health.In the health assessment criteria layer index,the health scores are ranked as:forest structure indicators>site condition indicators>resistance indicators>productivity indicators.The scores of different forest type health indexes were compared:Picea crassifolia+Betula platyphylla mixed forest>Picea crassifolia forest>Betula platyphylla forest>Populus cathayana forest>Larix principis-rupprechtii forest.(4)Person correlation analysis of forest health index and its influencing factors showed that shrub coverage,herb coverage,species diversity,humus thickness,slope direction,stock volume,average tree height and average DBH had greater impact on forest health.(5)Through the analysis of health assessment results and the current status of forest resources,it is indicated that the forests in Baoku River Basin currently have the following problems:single species structure,low proportion of plantation,unreasonable forest planning and excessive stand density,unreasonable forest structure and so on.In view of the corresponding problems,in the future forest health management,the forest structure adjustment,forest tending,planning timber forest and economic forest are proposed. |
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