森林復育個案研究：鑑定與減緩原生闊葉樹種的建立限制

Abstract

生態復育之目的乃為加速恢復目標生態系其組成與功能。為達到復育之目標， 進行原生森林植群重建時，首先考慮的問題為組成演替晚期樹種可能面臨的傳播 與建立限制。傳播限制包括缺乏種子供應源或傳播者，傳播途徑受阻等因素。建 立限制為影響種子發芽，及小苗後續存活及生長狀況的因子。本試驗於臺灣大學 實驗林和社營林區25 林班地柳杉人造林進行相關復育試驗，試圖探討欲恢復當地 原生植群時，殼斗科樹種面對之建立限制。試驗地進行不同林地處理，包括疏伐 與未疏伐，地被清除與保留地被，試驗方法為苗木栽植與種子直播，苗木栽植包 括一年生苗木及三個月苗木，種子直播則有新鮮種子及發芽種子。試驗結果顯示 若殼斗科種子能順利傳播至試驗地，則種子被移除乃為主要的建立限制，最終存 活率由高至低依序為一年生苗木、三個月苗木、發芽種子、新鮮種子。 本研究進一步嘗試種子直播是否可為森林復育方法，2009 至2012 年間直播試 驗，不同種類、不同發芽程度種子於不同林地處理樣區中均迅速被移除，僅2010 年青剛櫟及三斗石櫟發芽種子於疏伐樣區中保留地被穿越線上有成苗，成苗率分 別為1.8 與2.3%。架設圍網進行野外發芽試驗，瞭解種子未被移除，則能順利在 野外發芽成苗。本研究也針對主要取食者－囓齒目動物，嘗試減少種子被移除的 物理及化學方法，物理方法包括埋土及覆蓋凋落物僅能延遲種子被移除，未能促 使種子順利成苗，化學方法為噴灑肉桂酰胺及桂皮醛忌避劑則未看出效果。試驗 結果顯示欲減緩建立限制，栽植一年生苗木為最有效方法。

Ecological restoration is an intentional activity to accelerate the recovery of health, integrity, and sustainability of a deteriorated ecosystem. When restoring native forest vegetation, we usually face two limitations, namely, dispersal and establishment limitations. The former would occur when the dispersal path is blocked(e.g., lack of seed sources or dispersal agents). Establishment limitations refer to the factors that hinder the germination of the dispersed seeds, as well as the survival and growth of seedlings. Based on direct seeding and seedlings planting experiments, the objectives of this study are to identify and alleviate the likely factors affecting the establishments of native Fagaceae species during the restoration of a Japanese cedar plantation to native forest vegetation in a site located at the Heshe District of NTU Experimental Forest. After four years of direct seeding and seedling planting, this study found that, if seeds are able to disperse into the study site, acorn predation is the most important establishment limitation for the target Fagaceae species. Different site preparation methods, such as thinning and vegetation removing, have no significant effects in reducing acorn predation rate. Plating one-year-seedlings has the highest success rate, followed by planting three-month-seedlings and direct seeding of germinating acorns, whereas direct seeding of fresh acorns has the lowest success rate. Plastic nets can iv effectively deter acorn predators and enhance acorn germination and seedling survival rates. The physical and chemical methods that the study experimented to prevent seed predation are not effective. The results of this study suggest that planting one-year-old seedlings will be the best way to alleviate the establishment limitations when restoring the Japanese cedar stands to native forest vegetation in the study area.