关帝山云杉次生林树木更新与土壤养分的空间关联性

Spatial associations between tree regeneration and soil nutrient in secondary Picea forest in Guandi Mountains,Shanxi,China

参照CTFS(Center for Tropical Forest Science)技术规范在山西关帝山4 hm^(2)样地(GDS样地)190个采样点进行调查,研究样地更新苗的分布,以及土壤有机质、有效氮、有效磷、有效钾等养分及pH值等14个土壤指标的空间格局,分析树木更新与土壤养分分布的空间关联性,探究云杉次生林树木更新格局的形成机制。结果表明:土壤有效氮、有效钾、有效铜、有效铁、有效锰、有效镍及有效锌含量低的斑块中更新苗存活数量较多,且除有效钾外其他6个土壤养分因子与地径(GD)相对较大的Ⅱ(2.5 cm<GD≤4 cm)、Ⅲ(4 cm<GD≤5 cm)径级更新苗数量的负相关性高于Ⅰ级(0 cm<GD≤2.5 cm)更新苗,表明这些土壤养分对较大径级的更新苗分布影响更大,更新苗在存活过程中表现出对土壤更强的依赖性。GDS样地土壤呈偏弱酸性(5.5<pH<6.8),pH值的增大伴随着有效铝含量的降低,有利于树木的更新和存活。土壤有效氮、有效钾、有效铜、有效铁、有效锰、有效镍、有效锌、有效铝及pH值9个土壤因子对GDS样地树种更新分布影响的总解释量为19.7%。

According to the technical specifications of CTFS(Center for Tropical Forest Science),190 sampling points of 4-hm^(2) plot(GDS plot)in Guandi Mountains of Shanxi Province,China were investigated to examine the spatial distribution pattern of seedlings and 14 soil indicators,including pH value and nutrient indicators.We analyzed the spatial associations between tree regeneration and soil nutrients,explored the mechanism of tree regeneration pattern of secon-dary Picea forest.The results showed that more seedlings survived in the patches with low contents of available N,available K,available Cu,available Fe,available Mn,available Ni and available Zn.Besides available K,the negative correlation between the other six soil nutrient factors and the number of regeneration seedlings of theⅡ(2.5 cm<GD≤4 cm)andⅢ(4 cm<GD≤5 cm)diameter classes with relatively large ground diameter(GD)was higher than that in theⅠdiameter class(0 cm<GD≤2.5 cm),indicating that soil nutrients had a greater influence on the distribution of regeneration seedlings in larger diameter class,and that the survival of regeneration seedlings was more dependent on soil condition.The soil of GDS was slightly acidic(5.5<pH<6.8).The increase of soil pH was accompanied by the decrease of available Al content,which was conducive to the regeneration and survival of trees.The total explanation of nine soil factors(including soil available N,available K,available Cu,available Fe,available Mn,available Ni,available Zn,available Al and pH value)on the regeneration and distribution of tree species in GDS plots was 19.7%.