Regional legacies of logging: Departure from presettlement forest conditions in northern Minnesota
Regional legacies of logging: Departure from presettlement forest conditions in northern Minnesota
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DOI：
10.1890/04-0748
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发表时间：
2005-04-01
影响因子：
5
通讯作者：
Reich, PB
中科院分区：
文献类型：
--
作者：
Friedman, SK;Reich, PB
加拿大和美国五大湖地区的森林100多年来一直是重要的木材生产资源。伐木和灭火对这些森林造成了重大但无法量化的变化，其中包括组成变化的幅度及其空间格局。因此，一个空间上明确的区域尺度变化分析进行了使用一般土地办公室调查记录从19世纪末和1990年美国林务局库存和分析调查，在美国明尼苏达州东北部的320万公顷的研究区域。这些数据文件改变物种丰度，比例断面积和空间分布格局。在区域上，比例最丰富的物种转移到定居前时期（云杉，21%;落叶松，15%;和纸桦，15%），白杨（30%），云杉（16%），香脂冷杉（16%）在1990年。在比例断面积优势度方面，白松从20%下降到5%，桦树从16%下降到13%，云杉从14%下降到9%，落叶松从12%下降到2%，而白杨从8%上升到35%。基于排序的物种丰度和比例断面积，不同的地质和水文的自然地理区的特点是不同的物种组成，在19世纪，经历了很大程度上平行，而不是收敛的变化，自那时以来，在社区compositions.Maps开发的区域研究领域使用10 × 10公里的空间分辨率，以文件的空间格局的物种比例断面积。白松在253个100 km（2）的移民安置区中占45%，但在1990个移民安置区中没有白松。由赤松、短叶松和落叶松共同占据的森林地带也基本消失。这些森林在很大程度上被白杨共同占主导地位的社区所取代，占1990年森林区的82%，代表了区域景观多样性的减少。尽管1990年和19世纪森林中的物种相同，但它们的相对丰度和优势度发生了深刻的变化，253个区域中的85%现在包含群落类型（即，优势物种对），在定居前的时代没有占主导地位的任何地方。
Forests in the Great Lakes region of Canada and the United States have been important timber producing resources for more than 100 years. Logging and fire suppression have caused major, but unquantified change in those forests, which includes both the magnitude of compositional change and its spatial patterns. Hence, a spatially explicit regional-scale change analysis was conducted using General Land Office Survey records from the late 1800s and the 1990 U.S. Forest Service Inventory and Analysis Survey, for a 3.2 million hectare study area in northeastern Minnesota, USA. These data document altered species abundance, proportional basal area, and spatial distribution patterns. Regionally, the proportionally most abundant species shifted from the presettlement period (spruce, 21%; larch, 15%; and paper birch, 15%) to aspen (30%), spruce (16%), and balsam fir (16%) in 1990. In terms of proportional basal area dominance, white pine declined from 20% to 5%, birch from 16% to 13%, spruce from 14% to 9%, and larch from 12% to 2%, while aspen increased from 8% to 35%. Based on ordination of species abundance and proportional basal area, physiographic zones varying in geology and hydrology were characterized by different species composition in the 19th century and experienced largely parallel rather than convergent shifts in community composition since that time.Maps were developed for the regional Study area using a 10 X 10 kin spatial resolution to document spatial patterns of species proportional basal area. White pine co-dominated (was ranked first or second in proportion of basal area) 45% of the 253 100-km(2) presettlement zones, but none of the 1990 zones. Forest zones co-dominated by red pine, jack pine, and larch also largely disappeared. These forests were largely supplanted by aspen co-dominated communities, which accounted for 82% of the 1990 forest zones and represent diminished regional landscape diversity. Although the same I I species made up the 1990 as well as the 19th century forest, change in their relative abundance and dominance was profound such that 85% of the 253 zones now contain community types (i.e., dominant species pairs) that did not dominate anywhere in the presettlement era.