修枝抹芽对红椿幼林生长及干形的影响

Effects of pruning and sprouting on the growth and stem form of young Toona ciliata plantation

对2年生红椿幼林开展了修枝抹芽试验:第1年修去全部侧枝,第2、3年分别修去树高1/2以下的枝条及霸王枝,修枝后均在树干上的萌芽不超过20 cm前进行抹除。3年修枝抹芽的结果表明:相对于不修枝,第1年修枝抹芽对胸径生长有一定的削弱作用,但从第2年开始可促进胸径的生长;修枝抹芽能促进树高、单株材积量和林分蓄积的生长,且促进作用有先增大后减小的趋势;第2年修枝的胸径、树高、单株材积量分别提高8.1%、5.7%、16.3%。第1-3年修枝抹芽对红椿幼林冠幅生长均有不同程度的削弱作用,冠长和冠长率显著降低,高径比略有增大,干形略为饱满,活枝以下树节的个数减少45.8%。综上所述,适度修枝抹芽能够促进红椿幼林的生长,有利于培养良好的干形及无节良材,该研究结果对红椿幼林侧枝管理提供了科学依据。

The experiment of pruning 2-year-old young Toona ciliata plantation was carried out.In the first year,all the lateral branches were removed.In the second and third years,the branches below 1/2 of the height and overlord branches were removed.The results of pruning for three years showed that pruning for the first year had a certain weakening effect on DBH growth compared with no pruning,but it could promote DBH growth from the second year.Pruning could promote the growth of tree height,individual volume and stand volume,and the promoting effect had a trend of increasing first and then decreasing.The DBH,tree height and individual volume of pruning for two years increased by 8.1%,5.7%and 16.3%respectively.Pruning and removing buds in the 1st to 3rd years all weakened the crown growth of the young Toona ciliata forest to varying degrees.The crown length and crown length rate were significantly reduced,the height-to-diameter ratio was slightly increased,the stem shape was slightly full,and the tree was below the live branches.The number of knots decreased by 45.8%.In conclusion,moderate pruning can promote the growth of young Toona ciliata forest,which is conducive to the cultivation of good stem shape and nodeless timber.The research results provide a scientific basis for the lateral branch management of young Toona ciliata forest.