红松果材兼用林适宜密度控制技术研究

Studies on Technique for Suitable Density Control of Pinus koraiensis Stand Used for Fruit and Wood

利用近50年的系统定位观测资料,分析红松果材兼用林不同林分密度与直径、树高、冠幅等主要测树因子的关系.结果表明：在中等立地条件下（14地位指数）,最佳的林分密度经验式为N=21 182×D^-1.1827.通过对现实林分的最佳密度调控,可改善林分质量,与对照比提高林木直径连年生长量15%～20%;提高树高连年生长量约5%左右,可大大缩短大径材的培育年限.通过对不同林分密度条件下的植被多项因子,土壤物理、化学性质测定与分析得出：林下植物物种多样性以及生物产量,随林分密度的增大而降低;土壤主要营养成分及土壤物理性状则有随林分密度降低而改善的趋势.历经20余年对红松果材兼用林和人工红松大径材培育的试验结果分析表明：林分结实量与林分密度、林龄有直接关系.在适宜的林分密度下,在丰年后的冬季对具备截干条件的林木截去3～4枝以上主干,可人为促使林木形成多头（叉干）,达到增加林木结实部位的目的,可明显提高林木结实量,改善林木质量,与对照比39年生林分一个丰年可提高结实量39 kg·hm^-2,净增产值约780元·hm^-2.

By using observation data over 50 years, the paper systematically analyzed the relations of different stand density with diameter, height, crown of trees and so on. The result showed that the suitable formula for stand density under moderate site condition （index of 14） was N = 21 182 × D^-1.1827. Stand quality was promoted by adjusting existing stand density. Compared with contrast, annual diameter and height increment were increased by 15% - 20% and 5%, respectively, which would greatly reduce the duration of breeding large pole. According to investigations of plant and analyses of physical and chemical property of soils under different density, species diversity and biomass were decreased with the increase of density. Conversely, the nutrition and soil physical property were enhanced with the decrease of density. Twenty years observation indicated that seed production had direct relations to stand density and age. Based on the standard of the research, under the conditions of suitable stand density, cutting 3 - 4 branches and trunk at the top of tree in the first winter after abundant year, multi-tips would be gotten. As a result, multiple coning branches would be reached. Combining with pruning, wood quality could be promoted and seed production would be greatly increased. In an abundant year, cones could be increased about 39 kg·hm^-2 and net benefit could be 780 yuan·hm^-2 in a 39 a stand.