红脂大小蠹的危害与林分生境关系的研究

为进一步掌握红脂大小蠢在陕西的危害规律,制订合理的防治措施,在陕西黄龙林区设立20 m×30 m的样地81块,调查分析了红脂大小蠢的危害与林分环境之间的关系,结果表明,该虫在陕两黄龙林区主要 为害胸径为15~32 cm油松。其中油松纯林的受害重于混交林,海拔1 270～1 420 m范围内的油松最易被害, 坡度较平缓林分中的油松被害亦较重;在山坡林中,下坡位和林缘的危害最重、上坡位次之、山脊和中坡处的 最轻,半阴坡及阴坡危害重。其原因可能与该虫的习性及对林分的湿度要求相对较高有关。

Study on the Relationship between the Damage of Dendroctonus Valens LeConte and Forest Habitat Condition

Dendroctonus valens LeConte, was one of the most destructive pests to Finns tabulaeformis, it's damage to trees was tightly associated with forest habitat condition. The relationship between forest habitat condition and the damage of Dendroctonus valens LeConte was studied at 81 sample areas in Huanlong county, Yichuan county, Hancheng county during 2002 to 2003. The results showed that this pest destroyed mainly the pines which its chest-high diameter were between 15 cm~32 cm, and the damage in pure pine stand is more severe than mixed stands. The pine stands in 1 270 m~1 420 m altitudes and in fattish slope were damaged severely. While at hillslope forest, the trees in lower slope and forest edge were damaged most severely, and then were the trees in middle slope and upper slope. The trees in -shade-slope and semishade-slope were also damaged severely. All those damage conditions were associated with the pest's behavior and its preference to high humidity