Consequences of seasonal snow cover for carbon cycling of world forests: direct and legacy effects

季节性积雪对世界森林碳循环的影响：直接影响和遗留影响

• 批准号: 1929709
• 负责人: David Bowling
• 金额: $ 52.53万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1929709&HistoricalAwards=false
• 关键词: Consequences; seasonal; snow; cover; carbon

Forests are host to much of the world's biodiversity, and also provide many benefits to society, including the provisioning of clean air and water, opportunities for recreational activities such as hiking and the acquisition of valuable resources including timber and medicines. Forests also provide a less-appreciated benefit to humans through the cycling of carbon dioxide (CO2) between the air and the trees. As humans add CO2 to the air through the combustion of fossil fuels for energy, the amount of carbon in the atmosphere accumulates. This extra CO2 in the air alters the natural greenhouse effect, and is changing temperature and weather conditions across the planet. Part of the CO2 added to the air by human activities remains in the atmosphere, while some of it is absorbed by the oceans and land, especially by our vast forests. As a result, forests currently provide an important mitigating effect for climate change, slowing the rate of change. Seasonally snow-covered forests cover a large amount of land around the world, storing carbon in both the trees and soils. However, these areas are being modified by changing climate conditions and it is unclear how changes in snowpack will affect the ability of forests to store carbon. This project will investigate the unique influence of the snowpack on carbon cycling by using data collected across the northern hemisphere at research flux tower sites. The results of this project will advance scientific understanding of snow and tree interactions and will also be shared with the public through many activities at the Natural History Museum of Utah, allowing visitors to engage with and ask questions about the project. Forests play a critical role in the global carbon cycle, exchanging large quantities of carbon with the atmosphere. World ecosystems release an order of magnitude more CO2 to the atmosphere via respiration on an annual basis than humans do via combustion of fossil fuels and land use change. However, forests remove just a bit more CO2 via photosynthesis than they release via respiration, and the annual net uptake of CO2 by land ecosystems is smaller than the human CO2 production. This provides an important mitigating benefit to the rate of atmospheric CO2 increase and associated climate change. However, there are many uncertainties about forest carbon cycling that prevent robust forecasts of ecological processes into the future. This project will provide mechanistic insight into carbon cycling in snow-covered forests worldwide. The project will investigate the role of snowpack in forest carbon cycling to uncover the mechanisms behind both direct biophysical and indirect controls that reflect cross-season biophysical and biogeochemical legacies. Nearly 600 site years of carbon cycle data at over 60 unique seasonally snow-covered forests available from the worldwide FLUXNET and Fluxnet-Canada flux tower networks will be used. These sites represent a broad range of climate conditions and will provide fundamental information on the controls of snow-mediated carbon cycle processes across seasonally snow-covered forests globally. This information is crucial for the advancement of terrestrial biosphere models, improving our understanding of carbon flux response in seasonally snow-covered ecosystems.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.

森林是世界上许多生物多样性的所在地，也为社会提供了许多好处，包括提供清洁的空气和水，提供远足等娱乐活动的机会，以及获得木材和药品等宝贵资源。 森林还通过空气和树木之间的二氧化碳（CO2）循环为人类提供了一个不太受重视的好处。随着人类通过燃烧化石燃料向空气中添加二氧化碳，大气中的碳量就会积累。空气中额外的二氧化碳改变了自然温室效应，并正在改变地球上的温度和天气状况。 人类活动增加到空气中的二氧化碳一部分留在大气中，另一部分被海洋和陆地吸收，特别是被我们广阔的森林吸收。 因此，森林目前对减缓气候变化具有重要作用，减缓了变化速度。 季节性积雪覆盖的森林覆盖了世界各地的大量土地，将碳储存在树木和土壤中。然而，这些地区正在受到气候条件变化的影响，目前还不清楚积雪的变化将如何影响森林储存碳的能力。该项目将通过使用在研究通量塔站点收集的北方半球的数据来调查积雪对碳循环的独特影响。该项目的成果将促进对雪和树木相互作用的科学理解，并将通过犹他州自然历史博物馆的许多活动与公众分享，让游客参与并询问有关该项目的问题。森林在全球碳循环中发挥着关键作用，与大气交换大量的碳。 世界生态系统每年通过呼吸向大气中释放的二氧化碳比人类通过燃烧化石燃料和土地利用变化释放的二氧化碳多一个数量级。 然而，森林通过光合作用去除的二氧化碳比通过呼吸释放的二氧化碳多一点，陆地生态系统每年净吸收的二氧化碳比人类产生的二氧化碳少。 这为减缓大气中二氧化碳的增加速度和相关的气候变化提供了重要的好处。 然而，森林碳循环存在许多不确定性，阻碍了对未来生态过程的可靠预测。 该项目将为全球冰雪覆盖的森林中的碳循环提供机械见解。 该项目将调查积雪在森林碳循环中的作用，以揭示反映跨季节生物物理和地球化学遗产的直接生物物理和间接控制背后的机制。 将使用全球FLUXNET和Fluxnet-Canada通量塔网络提供的60多个独特的季节性积雪森林近600个地点年的碳循环数据。 这些地点代表了广泛的气候条件，并将提供关于全球季节性积雪覆盖森林中雪介导的碳循环过程控制的基本信息。这一信息对于陆地生物圈模型的发展至关重要，可以提高我们对季节性积雪覆盖生态系统中碳通量响应的理解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Forests for forests: combining vegetation indices with solar-induced chlorophyll fluorescence in random forest models improves gross primary productivity prediction in the boreal forest

• DOI: 10.1088/1748-9326/aca5a0
• 发表时间: 2022-11
• 期刊: Environmental Research Letters
• 影响因子: 6.7
• 作者: Z. Pierrat;J. Bortnik;Bruce Johnson;A. Barr;T. Magney;D. Bowling;N. Parazoo;C. Frankenberg;U. Seibt;J. Stutz