The Study Of The Health Assessment And Stand Structure Configuration Of Artificial Robinia Pseudoacacia In Yan’an Suburb

The Robinia Pseudoacacia, which was one of one of the most extensive forest plantingin Yan’an city and occupies an important place in the suburban forest configuration, plays animportant function of soil and water conservation. Some studies have shown that locustplantation community structure is unreasonable, forest stand development slow or evendegradation. Therefore, this study tries to discuss the health status of the RobiniaPseudoacacia and the factors which influence it, from the perspective of health evaluation ofRobinia Pseudoacacia. Besides, we also discuss the late reformation and technical measures,which will play its important role as a suburb forest to provide the reference to the health ofRobinia Pseudoacacia management.(1) According to the survey on the23representative standard lots in the suburb of Yan’an, the results show that the forest age was mainly between11to24years and focused onbetween mid-maturation forest and mature forest. In addition, The overall benefit of forest islow, and the average tree height is9.45m, average diameter at breast height is14.2cm, theaverage density is1121N/hm2, the canopy density is0.382on average, the average seedlingsupdated is805.8N/hm2.(2)To constructe the plantation health evaluation index system of Robinia Pseudoacaciain Yan ’an suburb, we set up two class indexes: one class index was productivity, communitystructure, resistance, and soil conditions and two class index was tree volume, shrub andherbaceous biomass,crown breadth, crown ratio, crown density, total coverage, communitystructure, Shannon-Wiener index, seedling density, degree of pests and diseases, forest firedanger, the degree of human disturbing internsity, soil moisture content, soil bulk density, pHvalue, organic matter, total nitrogen, available phosphorus and available potassium.(3) To learn about the health condition of the Robinia Pseudoacacia, we calculated thehealth composite index using analytic hierarchy process. The results show that most of thesample plots, about14, are under sub health standard, for60.87%of the total, the averagehealth index was0.483. There were9sample plots which were under the health standard, for39.13%of the total, the average health index was0.600. Overall, the artificial RobiniaPseudoacacia of Yan ’an suburb was in the sub-health state, and its health index was0.529. (4) Through the correlation analysis about the health index have very significantcorrelation to the tree volume, crown breadth, canopy density, the degree of pests anddiseases, soil rapidly available potassium, and have significant correlation to total coverageand the degree of human disturbance.(5) On the basis of predecessors’ research, based on the existing problems, we studiedabout the ideal plantation structure of Robinia Pseudoacacia, and proposed targetedconfiguration adjustment strategy, mainly including adjusting the goals, the principles, theunit, the measure and so on. The specific route of configuration is: classifiing site type,determining the classification of small classes, making measures which ajust each small classtype to the target state, formulate the installment adjustments plan, evaluate the configurationwhich formed after the adjustment stage.