臺灣中部山區天然林更新為孟宗竹林和柳杉林後之枯落物動態變化

Changes of Litterfall Dynamics after Converting Natural Forest to Moso Bamboo and Japanese Cedar Plantations in the Montane Area of Central Taiwan

鄭智馨(Chih-Hsin Cheng) ； 陳勇至(Yung-Chih Chen) ； 陳秋萍(Chiou-Pin Chen)

《國立臺灣大學生物資源暨農學院實驗林研究報告》 34卷3期 (2020/09) Pp. 245-268

https://doi.org/10.6542/EFNTU.202009_34(3).0005

摘要

本研究自2016年3月至2018年2月兩年期間，每月收集一次國立臺灣大學實驗林管理處溪頭營林區鳳凰山天然林及相鄰之孟宗竹林（Phyllostachys pubescens）及柳杉林（Cryptomeria japonica）之枯落物並加以分類，以了解天然林更新為人工林後，枯落物量、枯落物組成及其月變化。研究結果發現，三個林分第一年之枯落物量在統計上無顯著差異，第二年柳杉林之年枯落物量為三個林分中最低，且第一年之年枯落物量顯著高於第二年。除第一年9月因颱風干擾使柳杉林之枯落物量劇增外，天然林和孟宗竹林所有月份之枯落物量多顯著高於柳杉林。三個林分之枯落物皆具有季節性，但天然林和孟宗竹林之季節變化較柳杉林明顯。三個林分之枯落物組成以落葉為主，占全年枯落物比例之48.2±14.6%-71.2±6%。第一年天然林之次要組成為枝條（17.6±8.2%）、孟宗竹林為葉鞘（13.1±2.3%）及竹籜（14.5±9.7%）、柳杉林為繁殖體（20.5±3.7%）；第二年天然林之次要組成為繁殖體（21.7±1.7%）、孟宗竹林為葉鞘（21.1±1.5%）、柳杉林為繁殖體（24.8±8.4%）。天然林和孟宗竹林兩年之春、夏季因換葉皆出現落葉高峰，另第二年5－8月大量的降雨亦貢獻了孟宗竹林部分春、夏季落葉量。2016年9月的颱風不但造成三個林分當月落葉量及枝條量增加，也提升柳杉林繁殖體及孟宗竹葉鞘量。第二年春、夏季的連續降雨則對孟宗竹林之落葉、枝條、葉鞘及天然林的繁殖體有部分貢獻。

關鍵字

枯落物 ； 天然林 ； 孟宗竹林 ； 柳杉林

並列摘要

To understand the changes of litterfall production, major components and their seasonality after conversion of the natural broad-leaved forest to plantations, the litterfall under the natural broad-leaved forest and the adjacent Moso bamboo (Phyllostachys pubescens) and Japanese cedar (Cryptomeria japonica) plantations in Fenghuang montane area in Xitou tract of the Experimental Forest, National Taiwan University (NTU) was collected and classified once a month for two years from March 2016 to February 2018. The results indicated that the annual litterfall of three forests in the first year revealed no statistically significant difference. In the second year, the Japanese cedar plantation had the lowest litterfall production among three forests, and the litterfall of the Japanese cedar forest was significantly higher in the first year than the second. Except in September, when three typhoons caused the drastic increase in the litterfall of Japanese cedar plantation to increase the litterfall of Japanese cedar forest sharply, the monthly litterfall production of natural broad-leaved forest and Moso bamboo plantation were mostly significantly greater than that of the Japanese cedar plantation. The litterfall of three forests all showed the seasonality; however, the seasonal variation of the natural broad-leaved forest and Moso bamboo plantation seemed to be more significant than that of the Japanese cedar forest. The differences in leaf litterfall and annual litterfall production between two years were greater in the Japanese cedar plantation than in the other two forests. Leaf litterfall was the dominant component in all forests, ranging from 48.2±14.6% to 71.2±6%. In the first year, the second most important component was branches (17.6±8.2%) in the natural broad-leaved forest, leaf-sheathes (13.1±2.3%) and sheathes (14.5±9.7%) in the Moso bamboo plantation, and propagules (20.5±3.7%) in the Japanese cedar plantation. In the second year, the second most important components were propagules (21.7±1.7%) in the natural broad-leaved forest, leaf-sheathes (21.1±1.5%) in the Moso bamboo plantation, and propagules (24.8±8.4%) in the Japanese cedar plantation. In spring and summer, when the new leaves opened and the old leaves shed, there was a greater amount of leaf litterfall under natural broad-leaved and Moso bamboo forests. Besides, the high precipitation from May to August 2017 also contributed to the more leaf litterfall in Moso bamboo plantation. Typhoons that occurred in September 2016 increased not only the leaf and branch litterfall production of three forests but also the propagule litterfall in Japanese cedar plantation and leaf-sheath litterfall in the Moso bamboo plantation. The high precipitation from May to August 2017 increased the leaf, branch, and leaf-sheath litterfall in the Moso bamboo plantation and the propagule in the natural broad-leaved forest.

並列關鍵字

Litterfall ； Natural broad-leaved forest ； Bamboo plantation ； Japanese cedar plantation