Abstract:

The relation between the DTV (diversity threshold value) of artificial mixed forest and the percentage harm of Anoplophora glabripennis (Motschlsky) was analyzed by applying of the theory and technology of DTV, the diversity index of Margalef D_Ma, Shannon-wiener H, Pielon J_sw and the D_v of the value accumulated of diversity as the proportion of anti-pest tree species and pest infected tree' species changed from high to low. It showed that mixed forest of multiple tree species had a obviously resistance of pest damage of stem-borer, and the forest resistance ability was largely related to the pest resistance of the tree species and the percentage of the insect-resistant tree in the mixed forest. Under certain number of tree species in the mixed forest, the model of Logistic was accorded with the relation of the harm percentage P_z of A. glabripennis and D_v . The Logistic coefficient, α, was the starting value of the D_v and had a steady increase with the increased tree species; In the Logistic coefficient, the new meaning of r_m was that the force of resisting damage or potential pest-resistance for A. glabripennis, had a obviously increasing trend with, the increased tree species in the stands. Similarly, the same regularities were in maximum of D_ma , H and J_sw . In the mixed forest for 4～7 tree species, the increase of DTV followed the increase of tree species in the stands, on the contrary, the point of inflection of harm percentage L_vp decreased. Another value of the regularity was that the selection range of tree species of mixed forest will increase with the tree species' increasing in anti-pest forest which was designed or reformed.

Key words: mixed forest, Anoplophora glabripennis, diversity threshold value (DTV), pest resistance of the stands