Theory And Techniques Of Ecological Regulation Of Poplar Longhorned Beetle Disaster In Shelter-Forest

As for the poplar plantation, especially the "Three North" Shelterbelt Program, Poplar longhorned beetles (PLB) with a priority of Anoplophora glabripennis Motschulsky are the most important pest species that is extremely difficult to control.After briefly reviewing the evolutive history, developing background and features of the management strategy on forestry pests, the disaster outbreak and primary reasons caused by poplar longhorned beetles, and systematically synthesizing and commenting on the domestic & foreign research development of them, we expanded studies on theory and techniques of ecological management of poplar longhorned beetle disaster in Shelter-Forest in this paper. The main results are as follows:1. Base upon the existence of species diversity, structure complexity and space-time stability of forestry ecosystem, the concept and basic theoretic framework of "Sustainable Pest Management in Forest" were advanced.2. New ideas and foundations on classification of forest pest groups were firstly launched. According to quantity relationship between forest pests and species of their host trees in co-evolution process, forest pest groups were divided into Single Pest versus Single Tree (SPST) , Same Pest versus Different Tree (SPDT) and Different Pest versus Same Tree (DPST), respectively. According to the relationship between forest pests and their natural distribution areas, forest pest groups could be divided into Exotic Pest versus Exotic Tree (EPET ) , Exotic Pest versus Indigenous Tree (EPIT) , Indigenous Pest versus Exotic Tree (IPET) , and Indigenous Pest versus Indigenous Tree (IPIT). At last, the features and mutually internal relationships among the different groups were analyzed and discussed, their corresponding management strategies were then put forward .According to the disaster complex and distribution of A.glabripennis,in some area(such as north of China) ,the beetle disaster belongs to IPIT;but in other area,such as Heilongjiang,Ningxia and Qinghai etc,the beetle disaster belong to EPIT .Simultaneity,it is also SPDT.3. This paper put forward systematically and innovatively three key foundations forrationally allocating different tree species against pest disasters in artificial forest, namely: biodiversity causing stability of ecosystem, risk dispersing mechanism and relative resistance principle. Based on control technique levels and evaluation on PLB disasters, the strategies of rationally allocating different tree species against PLB disasters in shelter-forest were prominently analyzed, that is, from the view of controlling longhorned beetle disaster, according to the allocating structure of tree species and the defensive function against them, we defined in the paper the concept and traits of first-generation shelterbelt, second-generation shelterbelt and strengthened second-generation shelterbelt. Construction and scientific administration of the shelter forest system while rationally allocating different tree species is the fundamental measure to control the PLB disasters.4. This paper advanced the group division of major tree species in strengthened second-generation shelterbelt, defined the features of three kinds of trees: non-host trees, objective protection trees(=resistant tree) and luring trees, and their functions in ecologically regulating PLB disaster of shelter-forest for the first time. Furthermore, the principles of rationally allocating different tree species against PLB disasters in shelter-forest were systematically carried on, especially the principle of how to select luring trees, which includes site suitability, synchrony with the growth of objective protection trees, phase and relativity of attraction effect. Finally, luring effect and management techniques of luring trees were discussed, while the effect of rationally allocating different tree species against PLB disasters was also evaluated.5. The concept of Ecological threshold (ECT) in shelter-belt forest was expounded for the first time, and the distinctions between ECT and ET (econom...