松梢螟和云杉梢斑螟发生与林分及立地因子的关系OA

[Objective]This study aims to investigate the relationships between various stand and site factors and the occurrence of Dioryctria rubella and D.schuezeella larvae,so as to provide guidance for monitoring these two shoot moth species in forest areas.[Method]Field investigations were conducted on D.rubella larvae in Pinus tabuliformis forests and D.schuezeella larvae in Picea crassifolia forests in the Luoshan forests area of Ningxia.Nine stand factors were measured:stand density(x1),canopy closure(x2),tree height(x3),height under branch(x4),crown width(x5),DBH(x6),herb cover(x7),shrub richness(x8),and shrub diversity index(x9),along with five site factors:elevation(x10),humus layer thickness(x11),slope(x12),aspect(x13),slope position(x14),and corresponding larval population density.Stepwise regression analysis was used to identify the key factors influencing larval population density and to establish linear prediction models.Partial correlation analysis,analysis of variance(ANOVA),and multiple comparison tests were applied to analyze relationships between key factors and larval population density.[Result]Canopy closure,elevation,and slope were identified as the key factors affecting the occurrence of D.rubella larvae,while aspect,DBH,and shrub diversity index were the key factors affecting the occurrence of D.schuezeella larvae.The linear prediction models for larval population density were established as follows,for D.rubella:y1=208.565-0.075 x10-70.712 x2+0.865 x12,for D.schuezeella:y2=-100.995+17.268 x13+1.499 x6+60.596 x9.Elevation and canopy cover showed highly significant negative correlations with D.rubella larval population density(P＜0.01),whereas slope showed a highly significant positive correlation with it(P＜0.01).Aspect,DBH and shrub diversity index all exhibited a highly significant positive correlations with D.schuezeella larval population density(P＜0.01).[Conclusion]D.rubella larvae are more likely to occur in P.tabuliformis forests with canopy closure less than 0.62,elevation below 2 297 m,and slope greater than 39.1°.D.schuezeella larvae tend to occur in P.crassifolia forests on semi-shady slopes,with DBH greater than 24.83 cm and shrub diversity index greater than 0.33.These specific forest conditions should be prioritized for pest monitoring and control measures.