Understanding mycorrhizal associations to ensure the best start in life for trees, their carbon balance and future resilience

一个功能良好的森林生态系统是气候和土壤因素的融合，在树冠、林下和土壤层面具有生物多样性。高度的生物多样性和与土壤条件的兼容性大大增强了森林的复原力和适应能力。这增加了未来稳定的可能性，尽管气候变化带来了不确定性。在英国，要想成功地扩大森林覆盖率，必须了解一些制约因素，这样才能确保实现生物多样性、碳储存和功能目标。我们的战略是，通过了解和探索地下土壤、根系健康和地上树木健康之间的联系，从头开始建立有弹性的树木。外生菌根树不直接与土壤相互作用，而是通过真菌组织调节它们与养分、碳、水和微生物的地下相互作用。要了解树木如何与土壤相互作用，我们必须了解它们的菌根。树木将高达20%的碳分配给菌根真菌，作为回报，这些真菌几乎提供了树木宿主所需的所有常量营养素、微量营养素和水分。(Smith&Read，2008年菌根共生第三版)。最近的证据表明，在欧洲范围内，外生菌根多样性、树木生长、树木营养状况、氮沉积和土壤碳循环之间存在很强的联系，从而能够确定明确的环境阈值和指标(van der Linde等人，2018年《自然》；Suz等人，2021年新植物学家；Anthony等人，2022年isme J.)。这一新的理解如何转化为树木健康的局部和精细分辨率尺度，特别是在英国的背景下，并参考树木建立和未来的树木弹性需要进行调查。该项目将研究英国主要树种和混合树种的菌根协会与它们的生长、碳平衡、健康和弹性之间的联系。该项目将利用1,500个林地碳代码项目站点的子集，将一组树种和土壤类型的地下土壤碳和健康与地上森林碳和健康联系起来。该项目旨在：1.评估不同树种和混合物生长前20年的菌根真菌；2.比较生长在不同土壤类型(从营养贫乏到营养丰富)上的同一树种的菌根真菌群落及其功能探索类型；3.比较生长在相同土壤类型上的不同树种的菌根真菌和功能探索类型；以及4.测试菌根真菌与测量土壤和树木健康性状之间的关系。

A well-functioning forest ecosystem is an amalgamation of climatic and soil factors, with biodiversity at the canopy, understory and soil levels. The resilience and adaptive capacity of a forest is greatly enhanced by high biodiversity and compatibility with soil conditions. This increases the likelihood of future stability despite the uncertainty introduced by climate change. Much needed successful expansion of forest cover in the UK must be based on an understanding of a number of constraints, so the pathways to sustainable and resilient new planting of trees ensure that biodiversity, carbon storage and functional targets are achieved.Our strategy is based on building resilient trees from the ground up by understanding and exploring the links between belowground soil and root health and aboveground tree health.Ectomycorrhizal trees do not interact directly with soil, instead their belowground interactionswith nutrients, carbon, water and microbes are mediated through fungal tissue. To understand how trees interact with soils, we must understand their mycorrhizas. Trees allocate up to 20% of their carbon to mycorrhizal fungi and in return these fungi provide nearly all macronutrients, micronutrients and water needed by their tree hosts. (Smith & Read, 2008 Mycorrhizal Symbiosis 3rd ed). Recent evidence shows strong European-scale links among ectomycorrhizal diversity, tree growth, tree nutritional status, N deposition and soil C cycling, allowing the identification of clear environmental thresholds and indicators(van der Linde et al., 2018 Nature; Suz et al., 2021 New Phytologist; Anthony et al., 2022 ISME J.). How this emerging understanding translates to local and fine-resolution scales for tree health, particularly in UK settings, and in reference to tree establishment and future tree resilience needs investigation.This project will study links between mycorrhizal associations of the main British tree species and mixtures to their growth, carbon balance, health and resilience from the onset of tree establishment. This project will link belowground soil carbon and health with above ground forest carbon and health for a set of tree species and soil types using a subset of the 1,500 Woodland Carbon Code project sites. This is linked to an England Tree Planting Programme's Forest Research project assessing soil carbon change at Woodland Carbon Project Sites.This project aims to: 1. assess the mycorrhizal fungi of different tree species and mixtures in their first 20 years of growth, 2. compare mycorrhizal fungal communities as well as their functional exploration types for the same tree species growing on different soil types (ranging from nutrient-poor to nutrient-rich), 3. compare mycorrhizal fungi and functional exploration types for different tree species growing on the same soil type, and 4. test relationships between mycorrhizal associations with measured soil and tree health traits.