在台灣的自然環境分布當中，森林覆蓋的面積佔全部土地總面積的一半以上；而台灣的年平均降雨量也高達2500公釐以上，是全球平均降雨量的2.6倍之多，由此可見，台灣的自然資源豐富不致匱乏；但台灣每年平均每人的可用水量相對於全球人平均來說卻相對的少，夏季缺水的狀況也時有所聞；森林也因為缺乏相關完整的政令保護之下而遭到破壞，造成土石流等災害頻傳；因此，相關森林及水資源的研究一直是相當重要的議題。研究指出，森林與水資源間並無一致的關聯性，但卻明確的證實改變植生覆蓋率或組成會影響集水區的出水量；而集水區出水量受林木變更影響的程度隨雨量、優勢樹種、砍伐面積等因素的不同而有所不同。本研究將探討植相改變對於逕流型態的影響，研究採用福山試驗林2004及2006年的颱風季降雨資料，以及觀察葉面積指數的變動情況，討論植相的改變對於集水區流量的影響。研究結果將可應用在集水區林地土地利用規劃，以及水土保持措施的效益評估，並利用林地變遷及逕流的改變來判別災害敏感地，作為防災依據及災前防範措施。
The characteristic of the natural environment of Taiwan is abundant forest and precipitation; forest covers more than half of Taiwan. Although the annual rainfall is high, per capita water use is much less than the world average. Therefore, ongoing relevant research on forest and water resources should be emphasized. Many studies point out that forest and water resources have different relationships. However, changes in tree cover or pattern will affect runoff from forest watershed. Discharge will differ according to precipitation, trees and even planting areas. This study aims at assessing the influence of tree pattern on runoff using typhoon season rainfall records since 2000 at Fushan forest experiment station. Results may be applicable in watershed management as well as assessment of soil and water conservation benefits. It can be used in disaster sensitivity analysis and also as a basis for selecting appropriate disaster prevention measures.
