Can nutrients put the breaks on forest carbon capture?

由于森林是碳的净汇，增加森林覆盖被广泛宣传为有助于减缓气候变化的全球解决方案。在加拿大，联邦政府的目标是在未来10年内种植20亿棵树，以帮助实现温室气体减排目标。然而，森林生长和森林土壤碳固存高度依赖于氮和钙等其他养分的生态地球化学循环，而这些养分已被数百年的人类活动所干扰。此外，气候变化可能会影响森林的健康和组成，进一步影响净碳储存。这项研究计划将氮和钙的土壤地球化学变化与森林生长和健康联系起来，重点是安大略南部，该地区由于酸性沉积而经历了广泛的土壤退化，该地区也是加拿大氮沉积水平最高的地区。作为安大略南部的关键物种，糖枫的健康和生长将成为研究的目标，但研究将包括安大略的一系列其他常见硬木树种。这项研究将包括四个补充项目，将提高我们对氮和钙在森林生长中的作用以及气候变化可能对森林健康产生的影响的理解。研究计划将问：1。大气氮沉降和土壤盐基阳离子状况如何影响树木生长和森林健康？2.气候变化如何影响树木健康？3.生长在贫基土壤上的森林对钙和/或氮的短期生物地球化学反应是什么？和4.土壤钙水平在收获和不收获的情况下会如何变化？这项研究将利用现有的10，000多棵树木的数据库，这些树木每年在100多个长期森林监测地块进行监测，并利用稳定同位素等创新技术来解开潜在的生物地球化学机制。它将联合收割机将广泛的实地采样和实验性实地研究与最先进的生物地球化学模型相结合，以评估当前的森林状况并预测未来在不同气候和管理情景下森林生长和健康的变化。这项工作将由一个多元化和包容性的HQP团队进行，该团队由3名博士生，2名硕士生，4名本科荣誉学生和一名研究技术人员组成，所有这些人都将与利益相关者合作，以确保这些研究的结果将直接传达并用于为政策决策提供信息。这项工作将能够更准确地估计硬木森林的未来健康和增长，这是政府应对气候变化政策的重要组成部分。它还将确定有助于森林管理决策的潜在缓解措施，这些决策可能包括需要修正、调整采伐做法和/或改变树种组成。

Increasing forest cover is widely promoted as a global solution to help mitigate climate change as forests are net sinks of carbon. In Canada, the Federal Government's objective is to plant two billion trees within the next 10 years to help meet greenhouse gas emission reduction targets. Forest growth and forest soil carbon sequestration, however, are highly dependent on the biogeochemical cycling of other nutrients, like nitrogen and calcium, which have been perturbed by centuries of anthropogenic activities. Furthermore, climate change will likely impact the health and composition of forests with further implications for net carbon storage. This research program will connect changes in nitrogen and calcium biogeochemistry with forest growth and health, focusing on southern Ontario, which has experienced widespread soil degradation because of acidic deposition and this region also receives the highest levels of nitrogen deposition in Canada. As the keystone species in southern Ontario, sugar maple health and growth will be targeted, but studies will include a range of other common hardwood tree species in Ontario. This research will encompass four complimentary projects that will enhance our understanding of the role of nitrogen and calcium in forest growth and what impact climate change may have on forest health. The research program will ask: 1. How are tree growth and forest health affected by atmospheric nitrogen deposition and soil base cation status?; 2. How is tree health affected by climate change?; 3. What are the short-term biogeochemical responses of forests growing on base-poor soil to calcium and/or nitrogen additions?, and 4. How will soil calcium levels change under harvest vs. no harvest scenarios? This research will utilize an existing database of more than 10,000 trees that are annually monitored at more than 100 long term forest monitoring plots and utilize innovative techniques like stable isotopes to disentangle potential biogeochemical mechanisms at play. It will combine extensive field sampling and experimental field studies with state-of-the-art biogeochemical models to assess the current forest condition and forecast future changes in forest growth and health under different climatic and management scenarios. The work will be conducted by a diverse and inclusive HQP team consisting of 3 PhD students, 2 MSc students, 4 undergraduate honors students and a research technician, all of whom will work with stakeholders to ensure that findings from these studies will be directly communicated and used to inform policy decisions. This work will enable a more accurate estimation of the future health and growth of hardwood forests, which is a vital component of government policy to combat climate change. It will also identify potential mitigation measures that will aid forest management decisions that may include the need for amendments, adjusted harvesting practices and/or changes in tree species composition.