| 摘要: |
| 【目的】揭示藏东南尼洋河流域高山松次生林的林分特征，研究主要林分因子与林龄的相互关系。【方法】以西藏林芝尼洋河流域17块高山松次生林样地实测数据为依据，测算林分密度、林分平均胸径、林分平均高、优势木平均胸径、优势木平均高、林分胸高断面积、林分蓄积量等主要林分因子，并按照五点取样法在每个样地内设置5个2 m×2 m的小样方进行林下更新苗调查。通过钻取标准木髓芯，运用LINTABTM6年轮分析仪确定林龄，采用回归分析等方法对尼洋河流域高山松次生林主要林分因子与林龄的相互关系进行分析。【结果】尼洋河流域高山松林属于优势种群，且种群稳定，各林分因子与林龄显著相关。林分的胸径分布随林龄增加呈现出中间高两边低的近似正态分布；林分密度与林龄之间存在极显著负相关关系（R2=0.816）；林分平均胸径、平均高、胸高断面积和蓄积量与林龄呈极显著正相关，R2分别为0.762，0.829，0.853和0.885，其与林龄之间的回归关系用幂函数方程拟合最好；优势木的平均胸径和平均高与林龄也具有极显著相关性，R2分别为0.790和0.914；林下幼苗更新数量变动较大（更新密度为0～9 000 株/hm2，平均为（2 912±2 986） 株/hm2），且与林龄无显著相关性。【结论】作为尼洋河流域主要建群种之一,该区域高山松次生林林分结构稳定，生长潜力大；主要林分因子与林龄之间存在显著相关性，林下更新苗数量差异较大且与林龄无显著相关关系。 |
| 关键词: 高山松次生林 林分因子 林龄 尼洋河流域 |
| DOI： |
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| 基金项目:西藏农牧学院高层次人才科研启动项目（RC201506）；西藏农牧学院林学专业卓越农林人才教育培养计划改革试点项目 |
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| Correlation between stand factors and stand age of Pinus densata secondary forest in the Niyang River watershed |
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WANG Xiaolan,CHEN Jiarui,YANG Xiaolin,et al
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| Abstract: |
| 【Objective】This paper aimed to explore stand characteristics of Pinus densata secondary forest in the Niyang River watershed in southeastern Tibet and understanding the relationships between main stand factors and stand age.【Method】Based on measured data of 17 sample stands in the Niyang River watershed,main stand factors including stand density,stand mean diameter,stand mean height,mean diameter and height of dominant tree as well as basal area and volume were estimated.In addition,5 sub-plots with size of 2 m×2 m were systematically installed in sample plot to collect the stand regeneration information.Cores at breast height of standard tree were taken using increment borer and the age of cores was analyzed by LINTABTM6 Tree Ring Analyzer at laboratory.Stand age was determined by the average of standard trees.Correlation between stand factors and stand age was obtained using regression analyses.【Result】The alpine pine forest was the dominant species in the Niyang River watershed.The population was stable and stand factors were significantly correlated with stand age.Diameter distribution of P. densata showed an approximately normal distribution characterized with high in middle and low in both sides,indicating that P. densata stands maintained a dominant and stable population.Stand density and stand age showed a significantly negative relationship with coefficient of determination (R2) of 0.816.Stand mean diameter,mean height,basal area and volume had significantly positive relationships with stand age with R2 of 0.762，0.829，0.853 and 0.885,respectively.The power equation fitted well to describe these relationships.Mean diameter and height of dominant tree were highly correlated to stand age with R2 of 0.790 and 0.914,respectively.Density of regeneration seedlings varied greatly among stands (0 to 9 000 individuals/hm2 with average of (2 912±2 986) individuals/hm2) and had no correlation with stand age.【Conclusion】As one of the constructive species in the Niyang River watershed,P. densata secondary forest had a stable stand structure and sustained a high growth potential.The main stand factors were significantly related to stand age.The seedling number varied greatly among stands with no significant correlation to stand age. |
| Key words: Pinus densata secondary forest stand factors stand age Niyang River basin |
