LTREB Renewal: Drivers of temperate forest carbon storage from canopy closure through successional time

森林干扰，如砍伐和火灾，通常会导致森林及其土壤中碳和养分的大量损失。几乎美国东部的所有森林都在从这样的干扰中恢复，无论是自然的还是人为的。然而，目前还不清楚是什么机制控制了干扰后森林碳和养分储量的恢复时间。同样不为人所知的是，植物生长、土壤发育和气候变化如何相互作用地调节老化森林中碳和养分的恢复。该项目使用密歇根大学生物站(密歇根大学生物站)(密歇根北部一个有110年历史的野外站)的长期试验田来调查森林变化如何导致整体碳捕获和储存。在全球范围内，森林从化石燃料燃烧中去除了大约四分之一的碳排放，而温带森林，如这里研究的那些，负责从大气中去除近一半的碳。然而，在过去的大规模干扰之后，随着森林的老化和成熟，森林是否会继续部分抵消人类产生的碳排放，目前还不确定。该项目提供了预测持续温带森林碳吸收的规模和持续时间，以及森林为社会提供纤维、燃料、栖息地和许多其他好处的能力所需的关键数据和机制理解。这一长期(10年)项目在其富有成效的头5年开始回答全球重大问题。研究人员正在对6个林地的森林和土壤进行测量。分别在1936、1948、1954、1980、1998或2017年被实验性砍伐和焚烧。这些砍伐和焚烧处理复制了20世纪初在实验林所在的五大湖区发生的更大规模的砍伐和焚烧。森林结构测量包括树木、树叶和树枝密度和排列的模式。土壤测量包括养分分布和有效性以及土壤碳通量。通过使用附近未被严重砍伐和焚烧的老森林(130年至200年)作为参照点，该团队正在将干扰、气候、土壤和植被控制与森林中代表美国北部以及加拿大、欧洲和亚洲类似地区其他森林的碳固存的长期模式联系起来。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Forest disturbances, such as clear-cutting and fire, typically lead to large losses of carbon and nutrients from forests and their soils. Virtually all forests in the Eastern US are recovering from such disturbances, whether natural or human-caused. It is, however, not well understood what mechanisms control recovery times of forest carbon and nutrient stocks following disturbance. Also not well known is how plant growth, soil development and climate variation interactively regulate recoveries of carbon and nutrients in aging forests. This project uses long-term experimental plots at the University of Michigan Biological Station (a 110-year-old field station in northern Michigan) to investigate how changes in forests lead to overall carbon capture and storage. Globally, forests remove approximately 1/4 of carbon emissions from fossil fuel combustion, with temperate forests, like those studied here, being responsible for almost half of that carbon removal from the atmosphere. However, it is uncertain whether forests will continue to partially offset human-derived carbon emissions as they age and mature following past large-scale disturbances. This project provides critical data and mechanistic understanding needed to predict the magnitude and duration of continued temperate forest carbon uptake, and the ability of forests to provide fiber, fuel, habitat, and many other benefits to society.This long-term (10-year) project began to answer globally significant questions in its productive first 5 years. Researchers are measuring the forests and soils in 6 forest stands (approx. 2 acres each) that were experimentally cut and burned in either 1936, 1948, 1954, 1980, 1998, or 2017. These cutting and burning treatments replicate larger-scale cutting and burning that occurred in the early 1900s across the Great Lakes region within which the experimental stands are nested. Forest structural measurements include patterns of tree, leaf, and branch density and arrangement. Soil measurements include both nutrient distribution and availability and soil carbon fluxes. By using nearby old forests (130- to 200-yr-old) that were not severely cut and burned as reference points, the team is linking disturbance, climate, soil, and vegetation controls to long-term patterns of carbon sequestration in forests that are representative of other forests across the northern U.S. and similar regions in Canada, Europe and Asia.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.