台灣杉人工林內已更新闊葉樹之經營策略

依據現場作業經驗，台灣杉人工造林地進入期中撫育階段(15~20年生，平均DBH約20cm )時，林下經常已有闊葉樹天然更新幼樹之出現。這些珍貴的原生闊葉樹種，正是目前生態系經營行動中的重要復育對象，如能配合恰當的期中撫育及相關育林作業，理應成為台灣杉人工造林地後續經營之重要資產。傳統之人工造林地期中撫育作業，多將其重點置於造林木之生長促進與形質改善，直到最近，方將研究及作業重點，擴及疏伐與修枝作業對生物多樣性與水土保持之影響，至於前項已天然更新闊葉樹資產之經營策略，則仍付闕如。本研究之目的乃針對此一珍貴資產進行經營策略規畫及現地驗證，除對台灣杉人工造林地內經由天然更新途徑發生之闊葉樹植群進行解析之外，亦將就不同型態與強度之期中撫育作業，對天然更新幼樹之影響進行監測，期能找出恰當的作業時機與作業模式，並擬訂台灣杉人工造林地已更新闊葉樹之經營策略。

Based on field operational experience, when artificial Taiwania afforestation stands enter the intermediate tending stage (15–20 years old, with an average diameter at breast height (DBH) of approximately 20 cm), naturally regenerated broadleaved saplings frequently emerge in their understories. These valuable native broadleaved tree species represent important restoration targets in current ecosystem management initiatives, and, when paired with appropriate intermediate tending and related silvicultural operations, they should serve as a critical asset for the subsequent management of Taiwania artificial afforestation stands. Traditional intermediate tending operations for artificial afforestation stands have primarily focused on promoting the growth and improving the stem form of planted trees. It was not until recently that the focus of research and operational practices expanded to the impacts of thinning and pruning on biodiversity and soil and water conservation, yet management strategies for the aforementioned naturally regenerated broadleaved tree assets remain scarce. The purpose of this study is to develop management strategies and conduct field validation for this valuable asset. In addition to analyzing the broadleaved vegetation naturally regenerated within Taiwania artificial afforestation stands, this study will also monitor the impacts of intermediate tending operations with varying types and intensities on naturally regenerated saplings, with the goal of identifying appropriate operational timing and models, and formulating management strategies for the regenerated broadleaved trees in Taiwania artificial afforestation stands.