三個相鄰人工林分主要樹種葉部養分及枯落物養分研究

Foliar Nutrients of Major Tree Species and Nutrient Return by Litterfall in Three Adjacent Plantations

鹿兒陽(Erh-Yang Lu) ； 張愛華(Ay-Hwa Chang) ； 呂德霖(Te-Lin Lu)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 18卷4期 (2004/12) Pp. 303-319

https://doi.org/10.6542/EFNTU.200412_18(4).0005

摘要

本研究在2001年10月至2002年10月間，於台大實驗林清水溝營林區木荷(Schima superba)、杉木(Cunninghamia lanceolata)、孟宗竹(Phyllostachys pubescens)三個人工林分進行枯落物收集及分析，藉以了解三個林分枯落物動態及其養分回歸狀況。三個主要樹種木荷、杉木、孟宗竹新鮮葉子的養分濃度具顯著差異，其氮、磷、鉀濃度隨葉齡增加而明顯下降，而鈣、錳、鋁濃度則隨葉齡增加而上升。三個林分的枯落物養分濃度亦具明顯差異，枯落物中落葉的養分濃度一般比枯枝（孟宗竹則是竹鞘加竹枝）為高。年枯落物最高的木荷林其桔落物養分含量最高，杉木林及孟宗竹林則依元素不同而其含量次之或最低；三個林分均以落葉對枯落物養分含量的貢獻最大。森林地表氮、磷、鉀、鐵濃度在三個林分間無顯著差異，而鈣、鎂、錳、鋅、鋁濃度在不同林分間差異顯著。木荷林的森林地表養分含量最多，杉木林次之，孟宗竹林最低，這與三個林分森林地表的乾物重高低順序一致。在枯落物中重量遠低於落葉的枯枝，在森林地表的養分含量所佔的比例大為增加。以木荷林為例，其森林地表中枯枝乾重及其所含養分甚至高過落葉，其主因為枯枝分解不易，大量累積地表所致。綜合上述結果，可知在同一地區種植不同樹種對養分循環影響極大，可能因此造成土壤性質的差異。

關鍵字

養分 ； 葉部養分 ； 枯落物 ； 養分回歸 ； 森林地表

並列摘要

To understand the litterfall dynamics and nutrient return into the soils, we analyzed the litterfall and forest floor collected from three adjacent plantations of Schima superba, Cunninghamia lanceolata, and Phyllostachys pubescens from October, 2001 to October, 2002. The nutrient concentrations in fresh leaves differed significantly among three major tree species (S. superba, C. lanceolata, and P. pubescens). The concentrations of N, P, and K in fresh leaves decreased significantly with increasing leaf age, whereas those of Ca, Mn and Al increased with increasing leaf age. In all three stands, the fallen leaves usually had the higher nutrient concentrations than the fallen branches (or fallen branches plus fallen leaf-sheaths in the case of P. pubescens stand). The elemental concentrations of fallen leaves differed among three major tree species, and the differences were not necessarily related to the differences in the fresh leaves. Since S. superba stand had the greatest amount of annual litterfall among three stands, it also had the highest nutrient content in the litterfall. Compared to the other components, the fallen leaves consistently contributed more to the nutrient content of the annual litterfall in three stands. The concentrations of N, P, K, and Fe in the forest floors did not differ significantly among three stands, whereas the concentrations of Ca, Mg, Mn, Zn and Al differed among three stands. The nutrient content was largely determined by the dry weight of the forest floor. Therefore, the nutrient content in the forest floor was the highest in S. superba stand, followed by C. lanceolata and P. pubescens stands. While the importance of the fallen branches in the annual litterfall was far lower than that of the leaf-fall, the proportion of the fallen branches in the forest floor increased considerably and so did the nutrient content of the fallen branches in the forest floor. The low concentrations of nutrients, especially N, in the fallen branches were probably one of the main reasons why the branches decomposed slowly and thus accumulated in the forest floor. These results suggest that different tree species planted on the same site could result in the great differences in nutrient cycling and in soil properties.

並列關鍵字

Nutrients ； foliar nutrients ； litterfall ； nutrient return ； forest floor