A Systems Analysis of the Global Boreal Forest: Fire as a controlling process in the North American boreal forest
A Systems Analysis of the Global Boreal Forest: Fire as a controlling process in the North American boreal forest
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全球北方森林的系统分析：火灾作为北美北方森林的控制过程
DOI：
10.1017/cbo9780511565489.006
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发表时间：
1992
期刊：
影响因子：
8.8
通讯作者：
S. Payette
中科院分区：
文献类型：
--
作者：
S. Payette
引言 植物群落和物种分布的主要模式是由在不同空间和时间尺度上运行的各种扰动机制引起的（Loucks 1970；White 1979；Bormann & Likens 1979 b；Delcourt、Delcourt & Webb 1983）。温带森林的发展受到与单个和多个树木倒塌相关的树冠扰动的控制，树冠扰动会产生小间隙（Henry & Swan 1974；Oliver & Stephens 1977），并且偶尔会沿着暴风雨路径产生较大间隙（Canham & Loucks 1984）。相比之下，北方森林的火灾干扰会产生各种大小的树冠间隙，并构成复杂环境梯度植被发育中最重要的群落过程之一（Heinselman 1981 b）。在景观层面，生态干扰导致植被镶嵌的时空发展，该镶嵌植被由不同年龄、面积范围和植物区系组成的林分斑块组合组成（Pickett & White 1985）。北方森林是世界上两大森林带之一；它覆盖超过 12·6 km 2 (Baumgartner 1979)。北美洲的环北森林部分在地理和生态上都构成了一个明确的生物群落（图 5.1），这里将就火灾干扰进行分析。北方森林（不包括科迪勒拉地区）横跨加拿大东部和西部纬度10°以上；它在哈德逊湾和詹姆斯湾以南以及阿拉斯加有所收缩。在大陆范围内，北方森林是一个植物区系贫乏的生物群落（Takhtajan 1986），只有九种树种在区域或整个范围内占主导地位，与密集林分中的弱树冠植物群和开放林分中普遍存在的隐花植物群共存。
Introduction Major patterns of plant communities and species distribution are induced by various disturbance regimes operating at different spatial and temporal scales (Loucks 1970; White 1979; Bormann & Likens 1979 b ; Delcourt, Delcourt & Webb 1983). The development of temperate forests is controlled by canopy disturbance associated with single and multiple treefalls creating small gaps (Henry & Swan 1974; Oliver & Stephens 1977) and, occasionally, larger gaps along windstorm tracks (Canham & Loucks 1984). In contrast, fire disturbance in the boreal forest creates all sizes of canopy gap, and constitutes one of the most important community processes in vegetation development along complex environmental gradients (Heinselman 1981 b ). At the landscape level, ecological disturbances result in the spatiotemporal development of the vegetation mosaic composed of an assemblage of stand patches of different age, areal extent, and floristic composition (Pickett & White 1985). The boreal forest is one of the world's two largest forest belts; it covers more than 12 6 km 2 (Baumgartner 1979). The North American segment of the circumboreal forest, which constitutes a well-delineated biome both geographically and ecologically (Fig. 5.1), will be analyzed here with respect to fire disturbance. The boreal forest (excluding the Cordilleran region) spans more than 10° of latitude in eastern and western Canada; it is somewhat contracted south of Hudson Bay and James Bay, and in Alaska. At the continent scale, the boreal forest is a floristically poor biome (Takhtajan 1986) with only nine tree species dominating regionally or throughout the range, in coexistence with a subdued under-canopy flora in dense stands and an ubiquitous cryptogamic flora in open stands.