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马尾松(Pinus massoniana)是长江上游低山丘陵区退耕还林的一个主要造林树种。为了解林窗调控下,马尾松人工林更新优势种在化学计量特征水平上受边缘效应的影响,该文选取四川省宜宾市高县马尾松人工林人工砍伐形成的7种面积不等的林窗,以林下为对照,分析了人工更新优势植物油樟(Cinnamomum longepaniculatum)叶片化学计量特征及其季节动态。结果表明:马尾松人工林林下与不同面积林窗边缘相比,不同季节各林窗边缘油樟叶片碳(C)含量、碳氮比(C:N)和碳磷比(C:P)均显著高于林下。随着林窗面积增大,油樟叶片C含量、C:N、C:P和N:P均先升后降,在中型林窗(400–900 m~2)边缘出现最大值。从春季到冬季,油樟叶片N、P含量显著下降后上升,C:N和C:P显著上升后下降,均在夏季有拐点。夏秋季林窗边缘油樟对养分吸收利用优于春冬季,边缘效应更显著。主成分分析结果显示,马尾松人工林不同大小林窗边缘油樟化学计量特征主要受林窗面积、相对光强及月平均气温影响。研究结果表明:625 m~2林窗边缘油樟有机质储存及养分利用效率在不同季节均有最大值,在化学计量特征水平上具有更显著的边缘效应。
Pinus massoniana (Pinus massoniana) is a major afforestation species in the lowland and hilly region of the upper reaches of the Yangtze River. In order to understand the effect of edge effect on the stomatal characteristics of regenerated Pinus massoniana plantations under the control of gap windows, seven kinds of forest with different areas were planted by artificial cutting of Pinus massoniana plantation in Yixian County, Sichuan Province. Under the forest, the stoichiometric characteristics of leaves of Cinnamomum longepaniculatum and its seasonal dynamics were analyzed. The results showed that the carbon (C) content, carbon to nitrogen ratio (C: N) and carbon to phosphorus ratio (C: P) of Pinus massoniana var.mongolica leaves in different seasons, Significantly higher than under the forest. With the increase of Gap size, C content, C: N, C: P and N: P in C. camphora first increased and then decreased, and the maximum appeared at the edge of 400-900 m ~ 2. From spring to winter, the contents of N and P in C. camphora decreased significantly and then increased. The C: N and C: P increased significantly and then decreased, both in inflexion in summer. Campanulaceae at the edge of summer and autumn gaps in the window absorb and utilize nutrients better than spring and winter, and the edge effect is more significant. The principal component analysis showed that the stoichiometric characteristics of oil camphora of Pinus massoniana plantation at the edge of Gap plantation were mainly affected by the area of Gap, relative light intensity and monthly mean temperature. The results showed that the organic matter storage and nutrient use efficiency of Oil Palm at the edge of 625 m ~ 2 gap had the maximum value in different seasons and had more significant edge effect on the stoichiometric level.