马尾松树针叶立体分布和模拟为害对树木生长影响的研究

１９９３￣１９９４年，对马尾松树进行调查研究后表明，１株１５年生松树针叶平均鲜重为２１１８ｇ，其外层１年生针叶占总重数６１％，内层２年生针叶占总重数３９％，１￣３轮枝叶占２５％，１￣４轮枝叶占７５％；针叶被害２５％时，留４轮枝叶可承受松毛虫１９条，是留３轮枝叶的２．４倍。

Study on Stereoscopic Distribution of Masson Pine Needles and on Influenae of Simulated Damage on Tree Growth

Investigations and studies from 1993 to 1994 on Masson pine showed that one 15 - yearMasson pine had 2 118g mean fresh weight needles, among which 1 - year needles of outer layer took 61%,2 - year needles of inner layer took 39%; needles of let-3rd whorl took 25%, of 1st-4th took 57%,According to 25% needles damaged, 4 whorles branches and needles could endure 19 Dendrolimus punctatus.Simulated damage experiment indicated that when pine needles removed respectively 30%, 50%, 90%. newneedles of the next year were short thin and soft, yield decreased respectively 30%, 45% and 65%. Varianceanalysis demonstrated that the optimal whorls kept for 15 - year pine were 7, minimum 4 whorls.