Quinquennial (half-decadal) carbon and nutrient dynamics in temperate forests: Implications for carbon sequestration in a high carbon dioxide world

温带森林五年（半十年）碳和养分动态：对高二氧化碳世界中碳封存的影响

• 批准号: NE/S015744/2
• 负责人: Douglas Clark
• 金额: $ 51.8万
• 依托单位: UK CENTRE FOR ECOLOGY & HYDROLOGY
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FS015744%2F2
• 关键词: Quinquennial; half; decadal; carbon; nutrient

Having more carbon dioxide (CO2) in the atmosphere has increased rates of photosynthesis, promoting greater tree growth and carbon storage in forests. This process is called 'CO2 fertilisation' and results in 2-3 billion tonnes of carbon being removed from the atmosphere each year, which is 25-30% of the carbon put into the atmosphere by human activity annually. CO2 fertilisation, thus, greatly reduces rates of global warming. The fight against climate change relies on CO2 fertilisation continuing into the future; the Paris climate agreement emphasises that global efforts are required to limit the amount of carbon we release to that which trees, soil, and oceans can absorb naturally. Increased carbon storage in mature forests, due to CO2 fertilisation, is considered to be the most important reason for the current carbon uptake. But, looking forward, it is highly uncertain whether such high rates of uptake will continue, because the production of plant biomass also requires the uptake of nutrients from soils. The availability of key nutrients (especially nitrogen and phosphorus) may severely limit the ability of trees in mature forests to continue to grow more rapidly. Studying mature forests is particularly important when determining whether nutrient availability may limit future carbon uptake by land ecosystems. Firstly, as discussed above, mature forests are likely the most important absorbers of carbon on land; secondly, nutrient availability is generally low in mature forests because the roots of mature trees may have already fully explored their soils in their search for key nutrients. If mature forests are unable to access more nutrients in the future and maintain their carbon uptake, then this would have major implications for our society. It would mean that we would have to reduce our carbon dioxide emissions by a greater extent, and more rapidly than currently expected, if we are to avoid the most serious consequences of climate change. Temperate forests currently absorb almost as much carbon as the emissions from all EU nations. While tropical rainforests are, of course, important, mature temperate forests are calculated to be fourfold more efficient at absorbing carbon, and so merit special attention. To be able predict how mature temperate forests will respond in the future, it is critical that we determine whether greater carbon dioxide concentrations in the atmosphere will allow mature trees in temperate forest to:1) take up more nutrients from soils, and/or,2) increase the efficiency with which they use available nutrients to produce new plant tissue.Manipulating CO2 for whole stands of mature forest is challenging and expensive, and until now there has been no experiment that would have allowed us to address the uncertainties discussed above. All this has changed with the establishment of a new experimental facility in mature oak forest in central England. Leveraging a £15m philanthropic gift and an equivalent University of Birmingham investment, a whole-ecosystem free-air carbon dioxide enrichment (FACE) experiment has been set-up, which is successfully forest patches to CO2 concentrations more than one third higher than current levels. In the FACE ecosystem, the canopy trees are at least 160 years old and the site has been forested for the last 400 years. QUINTUS aims to carry out the detailed measurements of nutrient cycling (more than 20,000 analyses) that are required to answer the two key processes outlined above and, thus, determine how a mature temperate forest responds to rising atmospheric CO2. This new experimental understanding will then be used to develop and test the next generation of the computer models which are used to predict future rates of climate change. QUINTUS will deliver a foundational change in our understanding of future C uptake in temperate forests, and in mature forests generally. Such an advance is urgently required and has major societal relevance.

大气中二氧化碳 (CO2) 的增加会提高光合作用的速度，促进树木生长和森林碳储存，这一过程称为“二氧化碳施肥”，每年会从大气中去除 2-30 亿吨碳。每年，人类活动排放到大气中的碳量有 25-30%，因此，应对气候变化的速度将持续到未来。巴黎气候协议强调，需要全球努力限制我们释放的碳量，使树木、土壤和海洋能够自然吸收，由于二氧化碳施肥，成熟森林中碳储存量的增加被认为是最重要的原因。但是，展望未来，这种高吸收率是否会持续存在很大的不确定性，因为植物生物质的生产还需要从土壤中吸收关键养分（尤其是氮和磷）。可能会严重限制在确定养分可用性是否会限制陆地生态系统未来的碳吸收时，研究成熟森林中树木继续快速生长的能力尤为重要。其次，成熟森林中的养分利用率通常较低，因为成熟树木的根可能已经在寻找关键养分时充分探索了土壤，如果成熟森林未来无法获取更多养分并维持其碳吸收量。 ，那么这将对这意味着，如果我们要避免气候变化造成的最严重后果，我们就必须比目前预期更大幅度、更快地减少二氧化碳排放量。尽管热带雨林当然很重要，但据计算，成熟的温带森林吸收碳的效率高出四倍，因此值得特别关注，以便能够预测成熟的温带森林将如何应对。未来，至关重要的是我们确定是否更大大气中的二氧化碳浓度将使温带森林中的成熟树木能够：1）从土壤中吸收更多的养分，和/或，2）提高它们将可用养分用于新植物组织的效率。控制整个林分的二氧化碳成熟森林的研究具有挑战性且成本高昂，到目前为止，还没有任何实验可以让我们解决上述不确定性，但随着在英格兰中部成熟橡树林中建立一个新的实验设施，这一切都发生了变化。 1500万英镑的慈善礼物伯明翰大学也进行了相应的投资，建立了一个全生态系统自由空气二氧化碳富集（FACE）实验，该实验成功地将FACE生态系统中的二氧化碳浓度提高了三分之一以上。树冠树龄至少有 160 年，该地点在过去 400 年里一直被植被覆盖。 QUINTUS 旨在进行养分循环的详细测量（超过 20,000 次分析）。回答上述两个关键过程，从而了解成熟的温带森林如何应对大气中二氧化碳浓度的上升，然后将利用这一新的实验理解来开发和测试下一代计算机模型，该模型用于预测未来的气候变化率。 QUINTUS 将为我们对温带森林和成熟森林未来碳吸收的理解带来根本性的改变，这种进步是迫切需要的，并且具有重大的社会意义。

项目成果

Representation of phosphorus cycle in Joint UK Land Environment Simulator (vn5.5_JULES-CNP)

英国联合陆地环境模拟器 (vn5.5_JULES-CNP) 中磷循环的表示

• DOI: 10.5194/gmd-2021-403
• 发表时间: 2021-12-07
• 期刊: Geoscientific Model Development
• 影响因子: 5.1
• 作者: M. Nakhavali;L. Mercado;I. Hartley;S. Sitch;Fern;a V. Cunha;a;Raffaello di Ponzio;L. F. Lugli;C. Quesada;K. Andersen;S. Chadburn;A. Wiltshire;D. Clark;G. Ribeiro;Lara Siebert;A. M. Moraes;Jéssica Schmeisk Rosa;R. Assis;J. Camargo
• 通讯作者: J. Camargo

Representation of the phosphorus cycle in the Joint UK Land Environment Simulator (vn5.5_JULES-CNP)

英国联合陆地环境模拟器 (vn5.5_JULES-CNP) 中磷循环的表示

• DOI: http://dx.10.5194/gmd-15-5241-2022
• 发表时间: 2022
• 期刊: Geoscientific Model Development
• 影响因子: 5.1
• 作者: Nakhavali M