台灣中部地區天然闊葉林生態服務價值之評估

Abstract

近年來生態系服務功能逐漸被重視，隨著自然資源利用以及社會需求的轉變，生態系提供的服務漸漸的不只是有形的材料，更多的是無形的功能，包含大氣調節、水資源調節、水資源供給等等。因為許多生態系服務功能難以估計，因此被廣泛的討論，進而產生出許多研究方法，利用現有的數據去推估某地的生態系服務功能的價值。 本文針對臺灣中部林業試驗所蓮華池三號試驗集水區進行木材蓄積量、碳吸存量及水資源涵養量項生態系服務功能之評估。蓮華池三號集水區之面積為3.40ha，透過市場價格法及替代成本法作生態系服務功能單價的估算，而生態系服務功能的供給量則分別以不同的方法評估，木材蓄積量以立木材積回歸式計算，碳吸存量以碳濃度換算，水資源涵養量以水平衡收支法計算，最後將生態系服務功能的供給量乘上單價便可算出生態服務價值。 本文研究結果的生態系服務功能價值範圍約為新台幣19.2~39.0萬元/ha/yr，功能價值由高到低分別為、水資源涵養新台幣17.5~32.5萬元/ha/yr、木材蓄積量新台幣1.8~2.5萬元/ha/yr、碳吸存新台幣0.02~4.1萬元/ha/yr。顯示出在蓮華池三號集水區內，隱藏的生態服務價值遠大於林木直接使用的價值，然而在尚未討論全部生態系服務功能的情況下，所得結果是被低估的，但仍可作為最小價值參考。未來若用於實際經營管理上，可藉由此結果和預期收穫作比較，決定經營管理手段是否有必要且有能有收穫。

In recent years, ecosystem services have gradually drawn people’s attention. Due to the changes in natural resources usage and needs of society, ecosystem services provide not only tangible materials, but also intangible functions including regulation of air, water and climate, and water supply etc. Since many ecosystem services are hard to estimate its values, the methodologies are widely debated and many research methods have been developed to evaluate values of ecosystem service including using existing data. The research site is the Lienhuachih Experimental Watershed No.3, a 3.40 ha evergreen broad-leaved forest. The valuation of ecosystem services is based on the market price method and the shadow project. However, the supply of ecosystem service functions can be evaluated in many different ways. Timber volume is estimated by volume equation. Carbon sequestration is derived from timber volume and carbon concentration. Conservation of water resources is estimated by water budget method. Finally, the total values of ecosystem services can be calculated by multiplying the individual value of ecosystem services functions with its corresponding price. The range of values of ecosystem services in this research is from 192 thousand to 390 thousand NT$/ha/yr. The order of the values of ecosystem services from high to low is conservation of water resources (175 thousand to 325 thousand NT$/ha/yr), timber volume (18 thousand to 25 thousand NT$/ha/yr) and carbon sequestration (0.2 thousand to 41 thousand NT$/ha/yr). This research showed that values of the intangible ecosystem services were higher than that of tangible forest products in the Lienhuachih Experimental Watershed No.3. However, there were many ecosystem services excluded from this research; hence, the value of the ecosystem services in this research was conservative. Nonetheless, the results can be regarded as the minimum value for this forested area. The applied valuation methods can be used in the management of forests in the future. Whether management of a forest area is necessary can be determined by comparing the values of ecosystem services and expected rewards.