Rapacious logging of the coniferous forests of Mount Ali continued throughout the Japanese colonial period and on into the 1960s. When a heavy rain fell in the high mountains 50 years ago, it took a week for the water to arrive at the lower reaches of the various drainage basins. Today, however, a mountain downpour can cause a flood in Chiayi within two hours.
當阿里山針葉林從日據時代一路至六○年代被砍伐殆盡，也才會五十年前山區大雨，洪水經過一星期才到得了下游，現在兩小時就直抵嘉義，都會常成淹水區。