Modeling Probability of Ignition in Taiwan Red Pine Forests

台灣二葉松林燃燒機率之模式推導

林朝欽(Chau-Chin Lin)

《台灣林業科學》 14卷3期 (1999/09) Pp. 339-344

https://doi.org/10.7075/TJFS.199909.0339

摘要

本研究主要目的在於推導台灣二葉松林地模擬人為林火之燃燒機率與氣象、燃料因子間之關係式。試驗於1998年8月至12月間在國有林大甲溪事業區進行，每月逢機選取3-5天進行燃燒試驗，方式為每一試驗日上午9時至下午4時間，採取台灣二葉松林地表燃料每隔一小時以家用火柴進行點燃試驗。燃燒試驗共計進行109次，其中46次燃燒成功。所得資料運用logistic模式進行迴歸分析，燃燒機率之迴歸分析首先採單因子推導，結果顯示燃料濕度及大氣相對濕度為最好之預測因子，判定係數分別為R^2=0.83（燃料濕度）、R^2=0.82（大氣相對濕度）；其次為複因子之迴歸式推導，結果顯示以燃料濕度、風速及燃料遮陰度三因子最能預測燃燒機率，其判定係數為R^2=0.93。本研究結果顯示上述之迴歸式可提供台灣二葉松林林火危險預測參考，但整體性之燃燒機率公式尚須在不同林型之林地進行相似試驗。

關鍵字

燃燒機率 ； logistic迴歸 ； 林火危險

並列摘要

The main purpose of this study is to model the relationship between simulated human-caused fires and biophysical variables related to meteorological factors and fuel properties in Taiwan red pine forests. The experiment was carried out from August to December 1998 in the Dajashi National Forest. Three to 5 days were randomly selected to conduct the experiment monthly. Ignitions were performed hourly by igniting wooden matches and dropping them simultaneously onto a fuel bed within the period from 9 a.m. to 4 p.m. on each sampling day. A logistic model was chosen to analyze the tests. One hundred and nine trials were conducted, and 46 of these trials were successful ignitions. Univariate and multivariate regression analyses were used respectively to fit the model. Results show that the best individual predictors were moisture content of pine needles (R^2=0.83) and relative humidity (R^2=0.82) in univariate regression analysis. Three variables, fuel moisture content of pine needles, wind speed, and fuel shading, fit the multivariate model (R^2=0.93). Results indicate that the equations can be used to help predict fire danger in Taiwan red pine forests.

並列關鍵字

ignition probability ； logistic regression ； fire danger