Human activities have changed forest composition of northeastern North America since European settlement by increasing the importance of pioneer shade-intolerant species, at the expense of shade-tolerant and long-lived species. This study used tree taxa lists from land survey archives (1842–1935) to document the pre-settlement forest composition in a heavily transformed region at the temperate-boreal interface in eastern Québec (Canada). Pre-settlement forests were dominated by a spruce-fir-white birch assemblage. Two additional assemblages were characterized by high relative frequency of the fire-adapted jack pine and poplar, suggesting that fire was an important factor of pre-settlement forest dynamics. Comparison with modern forest inventories (1980–2010) showed that trembling aspen, jack pine and red maple increased to the detriment of spruce, yellow birch, and white and red pines. The spruce-fir-white birch assemblage is now confined to high elevations and steep slopes, while the jack pine assemblage has extended its distribution and strengthen its association with sandy deposits. Surveyors’ fire observations revealed a high fire activity during the settlement period (1842–1971) and human ignitions were probably the predominant cause. While settlement fires are a likely explanation for the post-settlement increase of jack pine and trembling aspen, industrial logging and land clearing are important factors that could explain the decline of spruce and pines (red and white). Ecosystem-based forest management should aim to increase spruce frequency and dominance over disturbance-adapted (shade intolerant and fast-growing) species, and to restore yellow birch, cedar, white, and red pines in the plains sector where forest transformation has been the most important.

中文翻译：

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加拿大东部魁北克省 Saguenay-Lac-St-Jean 山谷欧洲人定居后的森林改造

自欧洲定居以来，人类活动以牺牲耐阴和长寿物种为代价，增加了先驱不耐阴物种的重要性，从而改变了北美东北部的森林组成。本研究使用土地调查档案（1842-1935 年）中的树木分类群列表来记录魁北克东部（加拿大）温带-北方交界处严重转变区域的定居前森林组成。定居前的森林以云杉-冷杉-白桦组合为主。另外两个组合的特点是适应火的长针松和杨树的相对频率较高，这表明火是定居前森林动态的一个重要因素。与现代森林清单（1980-2010 年）的比较表明，颤抖的白杨、杰克松和红枫增加了对云杉的损害，黄桦、白松和红松。云杉-冷杉-白桦组合现在仅限于高海拔和陡坡，而长针松组合扩大了其分布范围并加强了与砂矿床的联系。测量员的火灾观察显示，定居时期（1842-1971 年）火灾活动频繁，人为点火可能是主要原因。虽然定居火灾可能是定居后长针松和白杨增加的原因，但工业采伐和土地开垦是可以解释云杉和松树（红色和白色）数量减少的重要因素。基于生态系统的森林管理应旨在增加云杉的频率和对干扰适应（不耐荫和快速生长）物种的支配地位，并恢复黄桦、雪松、白、