The disturbance regime of an old‐growth forest in coastal California
The disturbance regime of an old‐growth forest in coastal California
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加利福尼亚沿海古老森林的干扰状况
DOI：
10.2307/3235729
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发表时间：
1993
影响因子：
2.8
通讯作者：
V. T. Parker
中科院分区：
文献类型：
--
作者：
J. Hunter;V. T. Parker
本研究涉及一种古老的常绿混交林的干扰机制，其树冠由杨梅、石果、门氏假杉、金索栎、威斯利泽尼栎和红杉组成。从整个 230 公顷的流域中随机选择 80 个树冠间隙。在抽样土地面积中，11.1% 至 16.6% 处于差距范围内。间隙面积的众数为 < 50m2，范围为 6–3437 m2。间隙是由障碍、折断、尖端和斜坡破坏形成的。尽管不到 10% 的抽样间隙是由于斜坡失稳造成的，但这些间隙占间隙内总土地面积的 43%。所有障碍均由黄杉属或杨梅属个体的死亡造成，其中大部分不规则形状的间隙是由杨梅属个体的广泛分枝的树干造成的，而由黄杉属和红杉个体死亡造成的间隙更大，平均分别为 119 平方米和 111 平方米，比石果属或杨梅属死亡造成的间隙更大，平均为 54 平方米和 52 平方米。斜坡凹形部分的间隙更常见，而朝北的斜坡上大间隙更常见。间隙的产生增加了对相邻树冠的干扰，一半的间隙是通过不止一次干扰形成的。
干扰机制与地形的关系、冠层物种生物学对间隙特性的影响以及间隙形成中涉及的重复事件都表明间隙模式及其特征存在细微的尺度变化。
This study deals with the disturbance regime of an old-growth, mixed-evergreen forest with a canopy composed of Arbutus menziesii, Lithocarpus densiflora, Pseudotsuga menziesii, Quercus chrysolepis, Q. wislizenii, and Sequoia sempervirens. 80 canopy gaps were randomly selected from throughout a 230-ha watershed. Of the land area sampled, 11.1 to 16.6 % was within gaps. Gap area had a mode of < 50m2 and a range of 6–3437 m2. Gaps were formed by snags, snaps, tips, and slope failures. Although < 10 % of the gaps sampled were due to slope failures, these accounted for 43 % of the total land area within gaps. All snags resulted from the death of a Pseudotsuga or Arbutus individual, the widely branched trunks of Arbutus individuals accounted for most of the irregularly shaped gaps, and larger gaps resulted from the death of Pseudotsuga and Sequoia individuals, averaging 119 and 111 m2 respectively, than from the death of Lithocarpus or Arbutus, averaging 54 and 52 m2. Gaps were more frequent over concave sections of slopes and large gaps were more frequent on north-facing slopes. The creation of a gap increased disturbance to the adjacent canopy, with half of the gaps formed through more than one disturbance.
The relationship of disturbance regime to topography, the influence of canopy species biology on gap properties, and the repeated events involved in gap formation all indicate a fine scale variation in the pattern of gaps and their characteristics.