大直径树的种群在美国各地正在增加
Paul J Chisholm1, Andrew N Gray2
1Clearwater Forest Analytics, Rapid City, SD 57702.
概括
大直径的树木对生态系统至关重要. 虽然大多数大树种群正在增长,但一些物种和地区,如内华达山脉,正在经历下降.
科学领域:
- 森林生态 森林生态
- 树种群动态 树种群动态
- 气候变化影响 气候变化影响
背景情况:
- 大直径的树木对于生态系统的健康和功能至关重要.
- 之前对大树种群的研究在地理上受到限制.
- 老大树可能容易受到气候相关的死亡.
研究的目的:
- 为了描述美国各地大直径树的种群.
- 分析中型 (50-100厘米DBH) 和大 (>100厘米DBH) 树木的分布和趋势.
- 评估大树的碳储存和种群变化.
主要方法:
- 美国的利用森林库存和分析 (FIA) 数据.
- 将树木分为中等 (50-100厘米直径的乳房高度 (DBH)) 和大 (>100厘米DBH) 的大小类.
- 分析了地块重新测量数据,以确定人口趋势和增长率.
主要成果:
- 大型树种群集中在西海岸;中型树更为普遍.
- 大型树木 (>50厘米DBH) 储存大量的活树碳:约75%在西方和约20%在东方.
- 总体而言,大型和中型树木种群正在增加,东部的增长率更高,除了塞拉内华达山脉的大型树木和几种个体物种的下降.
结论:
- 虽然大直径树种群显示出积极的整体趋势,但特定物种和地区的局部下降值得关注.
- 这些下降可能会导致局部环境影响显著.
- 持续监测对于了解和减轻对大树的威胁至关重要.
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