Forest Health Assessment In The Upper Reaches Of The North Canal

In this paper,the forest in the upper reaches of the North Canal is taken as the research object.Remote sensing image interpretation is adopted on the Arc GIS platform.Research data are obtained through onsite verification and sample land investigation.Choose ten indicators based on the sustainable development theory and biodiversity theory with reference to the existing literature and combined with the actual situation of the research area.AHP and entropy weight method are used to determine the subjective and objective weights,and then the subjective and objective weights are weighted to obtain the comprehensive weights.On this basis,the forest health status in the upper reaches of the North Canal was comprehensively assessed,and the results of the assessment were analyzed to put forward the opinions on the forest health management and sustainable development and management in the upper reaches of the North Canal.The specific research results are as follows:(1)The weights calculated by AHP subjective weighting and entropy objective weighting.From the calculation results of weights,we can see that the near natural degree,the degree of diseases and insect pests,the structure of forest age,etc.are the main influencing factors of the forest health assessment index system in the upper North Canal.(2)According to the principle of basic equivalence and the principle of nearest rounding,forest health can be divided into five levels: morbid,unhealthy,general health,sub-health and health.Among the 41 forest plots investigated in the upper reaches of the North Canal,2 plots are in healthy state;12 plots are in sub healthy state;9 plots are in general healthy state;10 plots are in unhealthy state;8 plots are in abnormal state.(3)On the basis of sample survey,using Arc GIS obtain the vegetation distribution map of the study area.Combined with the evaluation results of the forest sample area,the spatial health of the upper canal is evaluated by spatial interpolation.It is concluded that morbid forests in the upper basin of the North Canal account for 0.89% of the total forest area,unhealthy forests account for 27.4% of the total forest area,general healthy forests account for 45.29% of the total forest area,and sub-health forests account for the total forest area 24.31%,healthy forests accounted for 2.11% of the total forest area.(4)To explore the impact of human factors on forest health,taking Yanshou Town as an example,on the basis of spatial interpolation analysis.The average distance between forest land of different health states and the urban center was compared.The farther away from the town,the healthier the forest.The low scores of indicators such as biomass,soil water holding capacity,forest age structure,and naturalness result in low overall forest health scores in the upper Canal,and the impact of diseases and insect pests on forest health is greater.In forest management,it is necessary to strengthen the prevention and control of pests and diseases,take appropriate measures to improve soil water holding capacity,adjust the age structure of the forest,and increase near-naturalness,and follow the "near-nature" management method to manage forest vegetation.It is the key to the health of the forest in the upper reaches of the North Canal.