Forest Centers of Eastern America
Forest Centers of Eastern America
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东美洲森林中心
DOI：
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发表时间：
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影响因子：
2.9
通讯作者：
E. N. Transeau
中科院分区：
文献类型：
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作者：
E. N. Transeau
可以说，通过总结，北美东部被四大森林中心所占据：（1）东北针叶林，以圣劳伦斯盆地为中心，（2）落叶林，以俄亥俄州盆地和皮埃蒙特高原为中心，（3）东南针叶林，以南大西洋和海湾沿岸平原为中心，（4）以西印度群岛为中心的佛罗里达半岛南部的岛屿热带森林。这里所用的中心一词，意味着植物在一个地区达到最佳发展的分布思想。这种植被分区不是固定的，而是随着大陆的演变和气候变化而移动和增减。每一个地层都由许多社会组成，它们彼此之间具有一定的演替关系，这种演替关系取决于土壤因素，而土壤因素与地文变化的关系最密切。在两个中心之间的中间地带，当地的继承秩序是由来自每个相邻地层的社会组成的。已经发现，如果将同一测站的降雨量除以蒸发深度所产生的比值绘制在地图上，它们所显示的气候中心通常与植物分布中心相对应。此外，草原，草原，疏林和密林区的分布也清楚地表明。这是由这样一个事实来解释的，即这种比率涉及对植物生命最重要的四个气候因素，即温度，相对湿度，风速和降雨量。
It may be stated, by way of summary, that eastern North America is occupied by four great forest centers: (1) the Northeastern Conifer forest, centering in the St. Lawrence basin, (2) the Deciduous forest, centering in the lower Ohio basin and Piedmont plateau, (3) the Southeastern Conifer forest, centering in the south Atlantic and Gulf coastal plain, and (4) the Insular Tropical forest of the southern part of the Florida peninsula, centering in the West Indies. The term center as here used, implies the idea of distribution about a region where the plants attain their best development. Such vegetation divisions are not fixed, but move and increase or decrease in extent depending upon continental evolution and climatic change. Each formation is made up of many societies, bearing a definite successional relationship to one another, which being dependent upon soil factors may be best correlated with physiographic changes. In regions intermediate between centers, the local order of succession is made up of societies from each of the adjoining formations. It has been found that if the ratios produced by dividing the amount of rainfall by the depth of evaporation for the same station, be plotted on a map they exhibit climatic centers which correspond in general with the centers of plant distribution. Further, the distribution of grassland, prairie, open forest, and dense forest regions is clearly indicated. This is explained by the fact that such ratios involve four climatic factors which are of the greatest importance to plant life, viz temperature, relative humidity, wind velocity, and rainfall.