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而且仍然是极为重要的可持续资源，对就业、地方经济、国家经济、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缓解等都是如此。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种和非树种之间的相互作用、营养动态（如氮(N)输入，如来自固氮生物）、干扰制度（如火灾）、采伐系统等。我提出的研究将解决一系列问题，这些问题对于理解过去、现在和未来的限制和变化如何影响/影响/将影响重要的亚北方森林类型及其生产力至关重要。我的研究目标是：1。利用森林林分水平的CO2和H2O交换来确证和校准亚北方森林的树到林分水平的生长和生产力。将测量树级的CO2和H2O交换、茎直径每日到每年的变化（径向生长），以及茎的CO2和H2O通量测量（如树液通量和/或气体交换）。这些将扩大到林分水平（例如，使用Bowler等人2012年采用的方法）。到2016年，我将有9到10年的连续森林尺度涡旋协方差CO2和H2O通量测量，冠层测量（例如活的与死的，死树的倒下率）和涡旋协方差通量塔站点的地下呼吸，在我提出的基于2015年CFI奖给UBC合作者的研究期间，测量将继续进行。2. 通过检查径向生长（例如树木年代学和/或树木计）来检查树木固氮蓝藻对云杉和冷杉生长的影响（从低到高的树木水平丰度）。树到林分水平的生长和氮含量将与附生蓝藻生物量负荷、树水平的氮输入和土壤和寄主树的氮条件有关。与针叶树物种相邻的落叶（非作物）物种（如杨树属）的重要性将被研究它们在促进蓝绿苔藓负荷和针叶树从树木到景观尺度的生长速率方面的作用。大气氮沉降（干湿）将在实验树和场地或景观水平上确定。我计划使用稳定同位素（自然丰度和/或可能的富集）来阐明营养交换的方向和幅度。将在田间建立对树木附生菌负荷的长期控制，特别是蓝藻，并评估氮输入的变化，以及随后的附生菌演替。

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.