Determinants of Forest Recovery from Local to Regional Scales

近年来，全世界对促进迅速和广泛的重新造林的兴趣激增。在全球范围内，30%的森林被砍伐，另外20%的森林退化，导致生物多样性丧失，气候变化和其他关键生态系统服务的下降。为了应对这些问题，波恩挑战制定了到2030年在3.5亿公顷土地上重新造林的宏伟目标。但是，尽管科学家和实践者在恢复小面积土地方面非常成功，但如何将恢复规模扩大到如此大的面积的科学仍然缺乏。为了扩大重新造林的规模，我们首先需要更好地了解哪些因素促进了最快和最好的森林恢复。土地使用历史、景观中残留森林的类型和位置以及生物物理因素都很重要，但这些因素的相对重要性尚不清楚。此外，我们如何评估恢复取决于我们衡量的方面;树木可以迅速恢复，但原始森林的生物多样性需要更长的时间才能恢复。 除了生物多样性，重新造林有望恢复一系列其他生态系统服务。其中的关键是碳，许多通过碳信用额资助或旨在恢复木材供当地使用的重新造林项目优先考虑生物量的快速增长。但是，优先考虑一种生态系统服务如何影响其他生态系统服务？虽然我们对生态系统服务的时间动态和相互作用的理解仍处于初级阶段，但现有的少数研究表明，随着生态系统服务以不同的速率变化，非线性响应和长期权衡是常见的。（2）在地方一级，评估土地使用历史、恢复类型和景观背景对不同森林恢复措施的相对影响;（3）确定森林恢复过程中生态系统服务和生物多样性之间的权衡和协同作用;（4）扩大这些结果，以开发在区域一级优先考虑重新造林的模型。实地工作将在两个国家进行，即撒哈拉以南非洲的马拉维和厄瓜多尔;这两个国家都有很高的森林砍伐率，大量依赖森林的人口，该研究的结果将有助于阐明地块和区域层面森林恢复的一般原则，并开发优先造林的软件方法穿越了不同的风景全球范围内雄心勃勃的恢复目标是恢复生态系统功能的绝佳机会，但需要充分知情和深思熟虑的方法，以确保在景观水平及其他方面取得成功。

In recent years, there has been a surge of interest worldwide in promoting rapid and widespread reforestation. Across the planet, 30% of forests have been cleared and another 20% degraded, leading to biodiversity loss, climate change, and decline in other critical ecosystem services. In response to these issues, the Bonn Challenge has set the ambitious goal of reforesting 350 million hectares of land by 2030. But while scientists and practitioners have been very successful at restoring small areas of land, the science of how to scale restoration up to such large areas is still lacking. To scale up reforestation, we first need a better understanding of what factors promote the quickest and best forest recovery. Land-use history, the type and location of remnant forest in the landscape, and biophysical factors matter, but the relative importance of these is not clear. Moreover, how we assess recovery depends on what aspect we measure; trees can grow back quickly, but the biodiversity that characterized the original forest can take much longer to recover. Beyond biodiversity, reforestation promises to restore a suite of other ecosystem services. Key among these is carbon, and many reforestation projects, financed through carbon credits or aiming to restore timber for local use, prioritize the quick growth of biomass. But how does prioritizing one ecosystem service impact others? While our understanding of the temporal dynamics and interactions among ecosystem services is still nascent, the few existing studies suggest that non-linear responses and long-term trade-offs are common as ecosystem services change at differential rates.To address these challenges, here I am proposing to: (1) use satellite imagery to examine spatial patterns and drivers of reforestation at the regional scale; (2) at the local scale, assess the relative effects of land-use history, restoration type, and landscape context on different measures of forest recovery through time; (3) determine the trade-offs and synergies among ecosystem services and biodiversity as forests recover; and (4) scale up these results to develop models prioritizing reforestation at the regional scale. Fieldwork will be conducted in two countries, Malawi, in sub-Saharan Africa, and Ecuador; both countries have high rates of deforestation, large numbers of forest-dependent peoples, and have been planting millions of trees annually to meet their ambitious reforestation commitments.The results of this study will help elucidate general principles of forest recovery at the plot and regional levels and develop software approaches for prioritizing reforestation across landscapes. The ambitious restoration targets across the planet are a remarkable opportunity to restore ecosystem function but require well-informed and thoughtful approaches to ensure success at the plot to landscape levels and beyond.