森林是陆地最大也是最重要的生态系统,森林生态系统提供了木材供给、固碳、水源涵养等多种类型的服务,通过量化森林生态系统服务有利于决策者管理实现精准管理的目标,从而达到提高森林质量和缓解气候变化的作用。森林生态系统过程的复杂性和时空变异性为该领域的研究提供了丰富的研究内容,近几年来该领域的文献发表量增长迅速,为了了解当前森林生态系统服务价值评估研究进展情况,文章使用文献计量学分析法对国内外相关研究进展进行了分析总结。结果显示,中国在该领域研究的国际影响力逐年提升,在Web of Science数据库中,中国科学院在该领域具有最多的文献量;生态系统服务制图、文化服务、生态系统价值、森林景观资源恢复等九类是当前该领域研究的主要研究类别;国内外研究热点大体一致,主要可分为影响因素、评价类型、评价对象、评价方法与指标4个热点类型。文章基于文献聚类和热点分布,提出未来研究的发展方向主要是:气候变化和土地利用变化的影响;多类型的覆盖;方法优化与模型的开发与应用。
The response and recovery mechanisms of forests to damage from freezing rain and snow events are a key topic in forest research and management. However, the relationship between the degree of damage and tree age, i.e., whether seedlings, young trees, or adult trees are most vulnerable, remains unclear and is rarely reported. We investigated the effect of tree age on the degrees of vegetation damage and subsequent recovery in three subtropical forest types-coniferous, mixed, and broad-leaved —in the Tianjing Mountains, South China, after a series of rare icy rain and freezing snow events in 2008. The results showed that damage and recovery rates were both dependent on tree age, with the proportion of damaged vegetation increasing with age(estimated by diameter at breast height, DBH) in all three forest types and gradually plateauing. Significant variation occurred among forest types. Young trees in the coniferous forest were more vulnerable than those in the broad-leaved forest. The type of damage also varied with tree age in different ways in the three forest types. The proportion of young seedlings that were uprooted(the most severe type of damage) was highest in the coniferous forest. In the mixed forest, young trees were significantly more likely to be uprooted than seedlings and adult trees, while in the broad-leaved forest, the proportion of uprooted adult trees was significantly higher than that of seedlings and young trees. There were also differences among forest types in how tree age affected damage recovery. In the coniferous forest, the recovery rate of trees with broken trunks or crowns(DBH > 2.5 cm) increased with tree age. However, in the mixed and broad-leaved forests, no obvious correlation between the recovery rate of trees with broken trunks or crowns and tree age was observed. Trees with severe root damage did not recover; they were uprooted and died. In these forests, vegetation damage and recovery showed tree age dependencies, which varied with tree shape, forest type, and damage type. Unde
