长白山阔叶红松林主要树种凋落叶分解速率及其与叶性状的关系

Leaf litter decomposition rate of main tree species in broad-leaved Korean pine forest and its relationship with leaf traits

阔叶红松林是我国东北地区地带性顶级森林群落,对维持区域生态系统稳定性具有重要作用。对阔叶红松林内主要树种凋落叶分解过程及影响因素进行研究,有助于增加长白山阔叶红松林生态系统的基础数据,为明确阔叶红松林的养分循环和物质流动提供依据。选取了长白山阔叶红松林内30个常见乔灌树种和16个凋落叶性状,采用野外分解袋法和室内样品分析等方法研究了长白山阔叶红松林内主要树种凋落叶分解速率及其与凋落叶性状的关系。1年的野外分解实验表明,30个树种的凋落叶重量损失率表现出较大差异。不同树种凋落叶的重量损失率在20.56%—92.11%之间,以红松(Pinus koraiensis)质量损失率最低,东北山梅花(Philadelphus schrenkii)质量损失率最高。不同生活型树种的凋落叶在质量损失率上存在显著差异,以灌木树种凋落叶的质量损失率最高,小乔木次之,乔木树种质量损失率最低。Olson模型拟合结果表明,不同树种凋落叶的分解速率k以红松最低,瘤枝卫矛(Euonymus verrucosus)最高,分别为0.24和1.64。不同树种分解50%和95%所需的时间分别在0.43—2.86年,1.83—12.37年之间。相关分析表明,凋落叶初始物理性状、化学性状均能反映凋落叶的分解速率。其中以凋落叶厚度、氮含量(N)、磷含量(P)、木质素含量、木质素与氮含量的比值(L∶N)、木质素与磷含量的比值(L∶P)与凋落叶分解速率k的相关性较高,说明利用凋落叶的某些物理、化学性状在一定程度上可以预测凋落物的分解速率。

The mixed-broadleaved Korean pine forest is a typical forest in Northeastern China, which plays an important role in maintaining the stability of regional ecosystem. The researches on litter decomposition of broad-leaved Korean pine forest can enrich the basic data and provide reference for nutrient cycling in this area. In this study, we selected 30 tree species and 16 leaf litter functional traits. Using litter bag method in the field and laboratory analysis we study the leaf litter decomposition rate of main tree species in the mixed-broadleaved Korean pine forest and the relationships between leaf litter decomposition rates and the leaf litter functional traits. The main results are as follows.After 365 days of decomposition, the mass loss of 30 tree species ranged from 20.56% to 92.11%. The mass loss rate of Pinus koraiensis is the lowest while the mass loss rate of Philadelphus schrenkii is the highest. For the different life form tree species, there were significant differences in the mass loss rate among different life forms, with shrub species having the highest mass loss rate and arbor species having the lowest mass loss rate. The fitting results of Olson model showed the decomposition coefficients(k) of 30 tree species ranged from 0.24 to 1.64, with Euonymus verrucosus having the highest k and Pinus koraiensis having the lowest k. The time required for 50% decomposition takes 0.43—2.86 years for different species and the time required for 95% decomposition takes 1.83—12.37 years. Correlation analysis showed that 12 of the 16 traits were significantly correlated with leaf litter decomposition. Among them, leaf thickness, leaf N content, leaf P content, lignin content, lignin: N, lignin: P had a strong correlation with litter decomposition rate. Therefore, the decomposition rate of litter can be predicted by some physical and chemical properties of litter leaves.