修枝高度对西南桦拟木蠹蛾为害的影响

Effects of Pruning Height on Trunk Borer(Arbela spp.) Damage to Betula alnoides

以广西百色5年生西南桦人工幼林为研究对象,设置系列修枝高度开展西南桦修枝试验,调查修枝前以及修枝后3年内西南桦林分的拟木蠹蛾(Arbela spp.)为害状况,揭示修枝高度对拟木蠹蛾为害的影响。结果表明:修枝前以及修枝后3年内不同处理间西南桦林分总体感虫株率和受害单株虫口数无显著差异(p>0.05),但修枝后修枝段的感虫率和虫口数均低于对照(未修枝)相应区段,其中6m和7m修枝高度处理中修枝段感虫率与对照组相应区段差异均达显著水平(p<0.05);而且使拟木蠹蛾在树干上的集中分布段提升1.5m以上;说明合理修枝能够显著减轻修枝段的拟木蠹蛾危害,从而提高修枝段的木材质量,为西南桦优质大径材培育提供依据。

A pruning trail was conducted with serials of pruning heights in a five-year-old plantation of Betula al- noides at Baise City, Guangxi to reveal the effect of pruning height on the tree damages by the trunk borer, an in- sect of Arbela （Metarbelidae）. No significant differences （p〉0.05） were found in the general rate of infected trees within the stand and in the number of borer in a single tree before and 3 years after pruning. However, the infec- tion rate and the number of borer occurring in pruned sections of the tree trunk was significantly lower （p〈0.05） than those of the same sections of the control （without pruning）, in which the difference was significant in the pruning sections with the tree height of 6.0 m and 7.0 m, indicating that the concentrated distribution sections of borer in the tree trunk lifted 1.5 m. It was concluded that pruning with reasonable heights could significantly re- duce the damage of trunk in pruning section. These findings could provide scientific evidence for producing large- scale high-quality timber of B. alnoides.