沿海拔梯度武夷山3种典型森林凋落物及养分归还动态

为了解武夷山森林凋落物量和养分归还特征,对武夷山3个海拔典型森林的凋落物量和养分动态开展连续3年的监测。结果表明,常绿阔叶林(645 m)、针阔混交林(1 028 m)和针叶林(1 442 m)的凋落物总量分别为471.25、453.77和409.84 g/m~2,森林凋落物总量随海拔升高呈减少的趋势。武夷山3种典型森林的凋落物总量具有明显的季节变化,均呈双峰型,但常绿阔叶林与针阔混交林和针叶林的凋落物总量峰值和次峰值出现时间近似相反。3种典型森林凋落物中落叶占绝对优势(78.1%～87.6%),落枝和其他组分较少。武夷山3种典型森林凋落物的养分年归还量均表现为C N K P,且养分归还总量随海拔升高而减少。常绿阔叶林的凋落物量和养分归还量较高,可能与环境条件和植被特征相关。这为中亚热带森林生态系统养分循环和森林碳循环机理研究提供了理论依据。

Dynamics of Litterfall and Nutrient Return in Three Typical Forests of Wuyi Mountain along Altitudinal Gradient

To understand the characteristics of litterfall production and nutrient return in Wuyi Mountain forests, the litterfall production amount and nutrient return of three typical forests with different elevations were surveyed continuously for three years. The results showed that annual litterfall productions were 471.25, 453.77 and 409.84 g/m² in the evergreen broad-leaved forest (645 m), coniferous and broad-leaved mixed forest (1 028 m) and coniferous forest (1 442 m), respectively. Litterfall productions of three typical forests decreased along with the altitude. There were obvious seasonal changes in litterfall production of three typical forests with a bimodal pattern, which the occurrence time of peak and secondary peak in evergreen broad-leaved forest was approximately opposite to those in coniferous and broad-leaved mixed forest and coniferous forest. Among litterfalls, the leaves were dominant in three typical forests, accounting for 78.11%-87.55%, while twig and others were less. The total annual nutrient return from litterfall in three forests was C > N > K > P, and the total nutrient return was decreased along with the altitude. The amount of litterfall and nutrient return were high in the evergreen broad-leaved forest which might be related to environment conditions and vegetation traits. Therefore, these would provide the theoretical basis on researches in nutrient and carbon cycle in the subtropical forest ecosystem.