Establishment Of Health Diagnosis And Rejuvenation Protection Plan For Ancient Sophora Japonica Trees In Chongxin County,Gansu Province

Ancient trees are precious ancient germplasm and cultural resources of tourism,which play an irreplaceable role in maintaining regional ecosystems,biodiversity,inheriting Chinese culture,and cohesion of the national spirit.Located in the hinterland of the Loess Plateau,Chongxin County,Gansu Province is rich in ancient locust trees,especially ancient locust trees,accounting for 41.45%of ancient Sophora japonica L.At present,although the county has completed the resource census of ancient trees and famous trees,it lacks understanding of the structural characteristics,health status,and habitat quality of ancient tree resources,and there is great blindness and arbitrariness in the protection of ancient trees,and it is urgent to carry out ancient tree health diagnosis according to the resource characteristics of ancient trees,follow the principle of“one tree,one policy”to formulate a restoration protection plan,and improve the scientific nature of ancient tree protection.Based on the in-depth analysis of the resource structure and distribution characteristics of ancient S.japonica,this article selects 10 aboveground health evaluation indicators of ancient trees based on the principles of comprehensiveness,objectivity,system and balance,and uses the principal component analysis method to evaluate the health status of the aerial parts of ancient trees,and completes the comprehensive diagnosis of the health of ancient ancient trees based on the evaluation of trunk stability.Based on the analysis of the habitat quality of ancient trees,a restoration and protection scheme for healthy damaged ancient trees of locust trees was studied and proposed according to the principle of“one tree,one policy”.The main results are as follows.(1)There are 80 ancient S.japonica in Chongxin County,including 29 first-class ancient first-classtrees(accounting for 36.25%),36 second-class ancient second-class trees(accounting for 45.00%)and 15 third-class ancient third-class trees(accounting for 18.75%).The average density of ancient trees/km~2 and 0.094 trees/km~2 of ancient locust trees in the county was 0.094 plants/km~2,of which the density of first-class ancient locust trees was0.037 plants/km~2,the density of second～class ancient trees was 0.046 plants/km~2,and the third-grade was 0.019 plants/km~2;According to the distribution of the number of plants,Jinping Town had the largest distribution,with 38 plants(approximately 47.50%),followed by Huanghua Township,with 19 plants(accounting for 23.75%),and only Mulin Township had no distribution of ancient acacia resources.The diameter of the breast of ancient trees increases with increasing protection level.(2)According to the health index,the health status of ancient S.japonica is divided into five grades:health[0～0.82),sub-health[0.82～1.41),decline[1.41～2.01),extreme decline[2.01～3.18)and dying(3.18～4].The health ancient S.japonica in the county was average,with healthy plants and sub-healthy plants accounting for 57.5%,while declining plants accounted for 23.750%and extremely declining plants accounted for 17.50%.Among them:the health of the tertiary ancient S.japonica is the best,almost 87%are in sub-health or healthy state;The health and sub-health status of subhealth of the secondary ancient trees accounted for 66%;Most of the first-class ancient trees of first class are in a state of decline to extreme decline,accounting for 65%.(3)Based on Tree Radar Unit Detection System(TRU),the stability evaluation method of ancient S.japonica was established and the stability of ancient S.japonica was divided into four grades:stable,basically stable,risky,and dangerous.Among the 47 ancient S.japonica detected,8 were stable,22 were basically stable,13 were at risk,and 4 were dangerous.The stability showed a trend of deterioration with increasing protection level of ancient trees.Therefore,in the health diagnosis of ancient trees(especially the large ancient trees of the millennium),based the health evaluation of the above-ground part,it is necessary to fully consider the potential threat of hollow decay of the trunk to the survival of ancient trees,comprehensively make the health judgment of ancient trees,and take scientific reinforcement measures in time to ensure the safety of ancient trees.(4)Habitat quality is the main cause of damage to the health of the ancient S.japonica.The decline in Sophora acaurica growth is closely related to the high compactness of the0-40 cm surface 0-40 cm soil,poor air permeability,lack of N elements,low organic matter content,insufficient growth space,and serious human interference.(5)Based on the comprehensive health diagnosis of the above-ground part and the assessment of trunk stability,according to the principle of“one tree,one policy”for the problems that exist in habitat quality,the rejuvenation protection scheme was formulated for four ancient S.japonica with decline in growth,and measures were presented from the aspects of habitat quality improvement,root recovery,prevention of trunk empty rot and tree reinforcement.