火燒嚴重度之界定與評估：以武陵森林火災為例

Identifying and Evaluating Fire Severity: A Case Study of the Wulin Fire

林朝欽(Chau-Chin Lin) ； 邱祈榮(Chyi-Rong Chiou) ； 周巧盈(Chiao-Ying Chou)

《台灣林業科學》 20卷3期 (2005/09) Pp. 203-213

https://doi.org/10.7075/TJFS.200509.0203

摘要

本研究主要目的為找出森林火災跡地之地面因子與植生指數(NDVI)間之關係，發展出以植生指數作為界定與評估火燒嚴重度之客觀依據。以2002年武陵森林火災跡地為研究對象，依不同海拔高度，設置樣區20個進行地面調查，並配合SPOT衛星影像進行植生指數分析。火災跡地之火燒嚴重度分級判別依樹圍焦黑百分比、樹冠被燒百分比、地表枯枝落葉層殘存百分比、樹幹平均焦黑高、林木胸高直徑等5項作為依據，利用雙光譜圖區分樣區分佈趨勢，再聯結植生指數，可將植生指數值-0.055~0.013界定為重嚴重度級；其次植生指數界於0.014~0.103者為中嚴重度級；植生指數大於0.104~0.339者為輕嚴重度級。最後透過植生指數推估不同火燒嚴重度分級區域，結果顯示武陵火燒跡地受影響屬於重嚴重度級面積約7.84ha，中嚴重度級之面積約106.73ha，輕嚴重度級者面積約為236.35 ha。

關鍵字

火強度 ； 持續延燒 ； 雙光譜分析 ； 衛星影像 ； 植生指數

並列摘要

The main purpose of the present study was to develop a methodology to classify fire severity in a very short period following a fire. The methodology developed here correlates the relationship between ground data and Normalized Difference Vegetation Index (NDVI) from the SPOT satellite image. We surveyed the burned she of the Wulin fire, central Taiwan in 2002 and set up 20 plots at the different elevations. Flit severity was evaluated by determining the amount of stems charred, crowns consumed, and litter remaining, as well as scorch height and diameters of the trees. The results showed that fire severity consisted of 3 classes. All of them have high correlations with MDVI values. Among the 3 classes, the severity of the heavy class was related to MDVI value of -0.055~0.013. The moderate class was identified by MDVI value of 0.014~0.103, and the light class was associated with MDVI value of 0.104~0.339. Using the above criteria, only 7.84 ha was estimated as being in the heavy class, 1/3 of the total burned area (106.73 ha) was classified as being moderate, while most of the burned areas (236.35 ha) had just been lightly influenced.

並列關鍵字

fire intensity ； residence time ； bi-spectral analysis ； satellite image ； NDVI