日治時期，臺灣有七成以上的土地屬於林野，林業在臺灣產業上的重要性不言而喻。然而，至1930年代前，林業表現並不出色，殖民林業學者甚至稱之為「臺灣之恥」。不過，當臺灣進入戰時體制後，林業卻一反疲態，躍升為臺灣工業化研究者所說的「發展最速的產業」。本文旨在回答如此急遽地轉型是如何可能。本文的分析顯示，殖民林業家之所以會把1920年代的臺灣林業視為「臺灣之恥」，理由在於，日治初期以來，總督府林業部門一直努力打造一套能合理、有效率地經營臺灣闊葉林的體系，卻一直收到反效果，甚至是引火自焚。1925年，林業部門決定改弦更張，推動以科學林業為基調的森林計畫事業，希望透過高強度的伐木與造林，以達到臺灣闊葉林的法正化。即便如此，由於林業部門錯估國際木材市場的波動，讓此耗費11年的計畫險以失敗告終。所幸，進入戰時體制後，在木材統制及軍部對闊葉材的高昂需求下，該計畫有了轉機。成立於昭和16年（1941）的南邦林業株式會社即是此轉機的產物。不過，即便總督府在南邦成立之際予其種種便利，期待可一舉達成闊葉林業的垂直整合，一方面為軍部提供量多質優的闊葉材，另方面完成臺灣闊葉林的法正化（即所謂的「保育」），經營初期的南邦卻因此蒙受極大損失。一直要到昭和18年（1943），當南邦逐步轉化為以在臺日本與臺灣業者為主體的本土會社，放棄不可行的垂直整合之法，轉而仰賴本島業者為中心的闊葉材生產網絡，林業部門構思的「保育」與開發的兩全之道方能實現。要之，本文嘗試同時打開殖民科學及資本主義此兩大黑箱，由此解開殖民統治、近代科學、工業化及環境變遷間錯綜複雜的關聯，從而對臺灣環境史做出貢獻。

During Japanese colonial rule, seventy percent of Taiwan's land was officially categorized as ＂rinya＂, literally meaning ＂forest and uncultivated land.＂ Hence, forestry would undoubtedly have played an important role in Taiwan's industrialization. However, until the late 1930s, the performance of forestry in colonial Taiwan had been so unimpressive that scholars in colonial forestry called it the ＂shame of Taiwan.＂ The rise of forestry occurred in the 1940s when the Japanese empire began its mobilization for military invasions; and forestry thus transformed into the ＂fastest-developing industry＂ in colonial Taiwan. This essay aims at answering how this remarkable transition could be made possible. The reason why colonial foresters deemed Taiwan's forestry the ＂shame of Taiwan＂ had everything to do with the failures or the ＂backfiring＂ of an array of seemingly rational and efficient policies implemented or imposed on Taiwan's broadleaf forests. As a result, from 1925 onward, colonial foresters endeavored to introduce the so-called ＂scientific forestry＂ from Germany to manage and conserve Taiwan's broadleaf forests through a project called shinrin keikaku jigyō. Nevertheless, the project was almost another failure owing to their underestimating the fluctuations of international market of timber. The favorable turn came when Japan mobilized for war, resulting in rising demand of broadleaf timber to meet military needs. In 1941, the Nanpō Corporation was established, comprising forestry entrepreneurs from both Japan and Taiwan, with the aim of finding a balance between military-oriented industrialization and conservation of Taiwan's broadleaf forests. Despite privileges offered by the colonial government, Nanpō suffered great initial losses when implementing national policies on vertical integration of forestry resources. By 1943, Nanpō switched to emphasize horizontal integration, relying on cooperation among local networks of timber production in Taiwan through distributing privileges it received from the colonial government among its stockholders. Discussion in this essay opens two black boxes tagged with ＂science＂ and ＂colonialism＂ respectively; untangling the network that involved colonial governance, modern science, industrialization, and environmental changes, thus contributing to our knowledge of Taiwan's environmental history during Japanese colonial rule.