一九八二年五月六日到六月十八日,我们在北山林场进行了有关蛀干害虫的专题调查,调查林分为约20年生的杉木纯林,海拔700—1100米。17块样地的杉木分别健康木和蛀干虫害木的胸径进行了实测,并对蛀干害虫危害后的杉木材积生长减少量作了估计。 From May 6 to June 18, 1982, we conducted a special survey of borers and pests in Beishan Forest Farm. The survey was conducted on pure Chinese fir forests of about 20 years old at altitudes of 700-1100 meters. The litter diameter of healthy and moth-eaten woods in 17 plots of Chinese fir was measured, and the reduction in the volume of Chinese fir after the damage of stem-borers was estimated.