台中大肚山台地土地利用及地覆變化趨勢之分析

Trend Analysis of Land-Use and Land-Cover Changes in Dadu Hill, Taichung

土地利用及地覆變遷的觀察，是研究人類在都市社會發展中的重要一環；透過對同一地區不同時期土地利用類型的分類及分析，進而瞭解變遷於何時發生、何處發生、以及如何發生。本研究嘗試以台中大肚山台地不同時期的土地利用類型資料，利用面積轉入及轉出量分析整體及個別土地利用類型變遷趨勢的研究。結果得知研究區的森林及農耕地面積量有逐漸減少的趨勢，森林的面積從1977年的2305.5公頃，到2002年已減少到808.3公頃，共減少了1497.2公頃；農耕地的面積從1977年的5893.6公頃，到2002年已減少到4274.6公頃，共減少了1619公頃；而開發地及草生地面積則是有逐年增加的趨勢，開發地的面積從1977年的2473.2公頃，到2002年已增加到3851.4公頃，共增加了1378.2公頃；草生地的面積從1977年的434.4公頃，到2002年已增加到1755.9公頃，共增加了1321.5公頃；且森林有逐漸轉變為草生地的趨勢，農耕地也有逐漸轉變為開發地的趨勢，再與前人於大肚山研究成果比較，推測其主要影響變遷的因素，前者可能在於林火干擾，後者則是人為開發。林火使得森林退化到疏林及草生地的土地利用類型，疏林亦有進一步退化成草生地的現象，雖然大肚山台地的原始植相為森林，有經自然演替回復至森林土地利用類型的可能，但因為火災干擾頻繁的關係，其回復的情形並不明顯。而農耕地轉入為開發地的原因，應該是跟台灣的經濟主軸由農業轉向工商業，造成農業及農耕地普遍式微有關。

Studies on land-use and land-cover change are important in rural, suburban, and urban areas. Classifying and analyzing land-use types during different periods clarifies the drivers of landscape change. This study applied 4-period land-use data in Dadu Hill to analyze changes in total landscape and individual land-use type. The result of this study showed that the total area of forest land and agricultural land gradually decreased, while that of developed land and grassland gradually increased. Forest land became grassland, and agricultural land became developed land. The area of forest land was 2,305.5 ha in 1977 and 808.3 ha in 2002, representing a 1,497.2 ha decrease. The area of agricultural land was 5,893.6 ha in 1977 and 4,274.6 ha in 2002, representing a 1,619 ha decrease. Furthermore, the area of developed land was 2,473.2 ha in 1977 and 3,851.4 ha in 2002, representing a 1,378.2 ha increase. Finally, the area of grassland was 434.4 ha in 1977 and 1,755.9 ha in 2002, representing a 1,321.5 ha increase. This study also compared its findings with the previous literature and concluded that the most likely explanations for the changes were forest fires and human construction. Forest fires led to forest land reverting savanna and grassland, after which savanna once again reverted to grassland. Agricultural land became developed land mainly through the Taiwanese economy evolving from being agricultural to industrial.