Limitations to sub-boreal forest growth and carbon sequestration from tree to forest scale before and after natural and anthropogenic disturbances.

不列颠哥伦比亚省中部的森林一直是并仍然是就业、地方经济、生物能源、纤维和木材产品生产和出口、生物多样性、娱乐、非木材产品和温室气体减排等方面极其重要和可持续的资源。 然而，这些森林的未来取决于我们对森林健康、生长和不断变化的环境（例如气候变化：特别是温度和水）之间关系的理解。 同样重要的是森林多样性的变化以及树木和非树木物种内部和之间的相互作用、养分动态（例如来自固氮生物的氮（N）投入）、干扰机制（例如火灾）、收获系统等。 我提出的研究将解决一系列问题，这些问题对于了解过去，现在和未来的限制和变化如何影响/影响/将影响重要的亚寒带森林类型及其生产力至关重要。我的研究目标是：**1。利用林分水平的CO2和H2O交换来证实和校准亚寒带森林的树木到林分水平的生长和生产力。将测量树木水平的CO2和H2O交换，每日至每年的茎直径变化（径向生长），以及关键的地上和地下植物茎的CO2和H2O通量测量（例如液流和/或气体交换）。 这些措施将扩大到林分水平（例如，使用Bowler等人2012年采取的方法）。 到2016年，我将有9到10年的连续森林尺度涡动协方差CO2和H2O通量测量，树冠测量（例如活树与死树，死树的下降率）和地下呼吸的涡动协方差通量塔网站，测量持续我提议的研究期间，基于2015年CFI奖给UBC的合作者。*2。通过研究径向生长（例如树木年代学和/或树木测定器），研究树栖固氮蓝藻（从低到高的树级丰度）对云杉和冷杉生长的影响。 树到立场水平的增长和N含量将检查相对于附生蓝藻生物量负载和树水平的N输入和土壤和宿主树木的N条件。 落叶（非作物）物种的重要性，如在属杨毗邻针叶树种将检查他们的作用，促进cyanolichen加载和针叶树的生长速度从树景观尺度。 大气氮沉降（湿和干）将在实验树和网站或景观水平。 我计划使用稳定同位素（天然丰度和/或可能的富集）来阐明营养交换的方向和幅度。 将在实地建立对树木上的真菌负荷，特别是氰地衣的长期操纵，并评估N输入的变化以及随后的真菌演替。

Forests in central British Columbia have been and remain a tremendously important and sustainable resource for employment, local to national economies, bioenergy, fibre and wood product production and export, biodiversity, recreation, non-timber products, and greenhouse gas mitigation to name a few. However, the future of these forests is dependent upon our understanding of the relationships between forest health, growth, and a changing environment (e.g. climate change: notably temperature and water). Also important are changes in forest diversity and interactions in and between tree and non-tree species, nutrient dynamics (e.g. nitrogen (N) inputs such as from N2-fixing organisms), disturbance regimes (e.g. fire), harvesting systems, and others. My proposed research will address a range of questions that will be critical for understanding how limitations and changes in past, present and future have affected/affect/will affect important sub-boreal forest types and their productivities. My research objectives are:***1. To use forest stand-level CO2 and H2O exchange to corroborate and calibrate tree- to stand-level growth and productivity of sub-boreal forests. CO2 and H2O exchange at the tree-level, daily to annual stem diameter changes (radial growth), and CO2 and H2O flux measurements for stem (e.g. sap flux and/or gas-exchange) for key over- and under-story plants will be measured. These will be scaled up to stand-level (e.g. using approaches taken in Bowler et al. 2012). I will have 9 to 10 years of continuous forest-scale eddy-covariance CO2 and H2O flux measurement, canopy measurement (e.g. live versus dead, fall-down rates of dead trees) and belowground respiration for the an eddy-covariance flux tower site by 2016, with measurements continuing for the duration of my proposed research based on a 2015 CFI award to collaborators at UBC. ***2. To examine the impact of arboreal N2-fixing cyanolichens (low to high tree-level abundance) on growth of spruce and fir by examining radial growth (e.g. dendrochronology and/or dendrometer). Tree- to stand-level growth and N content will be examined relative to epiphytic cyanolichen biomass loading and tree-level N inputs and N conditions of the soil and host trees. Importance of deciduous (non-crop) species such as in the genus Populus adjacent to conifer species will be examined for their roles in facilitating cyanolichen loading and conifer growth rates from tree to landscape scale. Atmospheric N deposition (wet and dry) will be determined at the experimental tree and site or landscape level. I plan to use stable isotopes (natural abundance and/or possibly enrichment) to clarify directions and magnitudes of nutrient exchanges. Long-term manipulations of epiphyte loadings on trees, particularly cyanolichen, will be established in the field and changes to N inputs evaluated, as well as subsequent epiphyte succession.**