Collaborative Research: P2C2--Growth Dynamics in the Climate Control of Tree-Ring Variability for Paleoclimatology

树木年轮是历史环境的重要自然档案。尽管这些记录具有巨大的价值和潜力，但关于年际生长层（树木年轮）碳储存速率和模式的重要细节仍然知之甚少。这些知识上的空白涉及到构成木材的组织的基本自然史。这项研究由亚利桑那大学和落基山树木年轮研究公司的科学家领导，旨在通过汇编数据集来改善树木年轮记录使用的科学基础，这些数据集包括每年关键树木生长过程开始的时间、每个过程的速度和持续时间，以及气候条件的日季节性变化与每个过程的时间、速度和幅度的关系。这将是美国西部首次进行此类研究。研究小组将在怀俄明州、科罗拉多州和亚利桑那州的四个地点收集数据，所有这些都集中在现有的通量塔设施上，包括在这一大地区用于树木气候学的主要树木类型。然后，他们将把树木的生长数据与空气、茎和土壤温度、水分有效性、树流和其他因素，以及物候事件（如梢伸长和针叶伸长）进行比较。这些数据和比较对于改进树木年轮生长控制的正演模型至关重要。这些方法基于树木年轮形成的良好气候控制过程模型，具有提高鲁棒性、扩展通用性和更好地评估基于树木年轮的气候重建的生物学有效性的潜力。这些方法也是新兴的贝叶斯古气候重建技术的核心，也是尝试使用合成代理记录测试重建方法的核心。这项研究的更广泛影响包括提高对过去气候的认识，提高对西部森林木材生长对最近或可能的未来气候的响应的认识和预测。后者是一个重要的实际问题，因为森林中的大部分碳都储存在木材中，这项研究的结果将进一步为预测应对气候变化的碳分配和储存提供信息。该项目将涉及本科生研究人员的实地和实验室工作，并发表结果。pi将直接通过公开演讲和媒体采访以及通过亚利桑那大学推广服务进行外联。

Tree rings are an important natural archive of past environments. Though these records have great value and potential, important details about rates and patterns of carbon storage in annual growth layers (tree rings) remain poorly understood. These gaps in knowledge concern the basic natural history of the tissue that forms wood. This research, led by scientists from the University of Arizona and Rocky Mountain Tree-Ring Research, Inc., aims to improve the scientific basis for the use of tree ring records by compiling data sets of when key tree growth processes start each year, the rate at which each proceeds and for how long, and how daily to seasonal variations in climate conditions relate to the timing, rate, and magnitude of each process. This will be the first such study in the Western US. The research team will collect data at four clusters of sites in Wyoming, Colorado and Arizona, all centered on existing flux tower facilities and including the major tree types used in dendroclimatology in this large region. They will then compare the tree growth data with air, stem and soil temperature, water availability, sapflow and other factors, as well as phenological events such as shoot extension and needle elongation. These data and comparisons are essential for improving forward models of tree ring growth control. The methods, based on and informed by sound process models of the climate control of tree ring formation, have the potential to improve robustness, extend generality, and better assess the biological validity of climate reconstructions based on tree rings. Such methods are also central to emerging Bayesian techniques of paleoclimate reconstruction, and to attempts to test reconstruction methodologies using synthetic proxy records.The broader impacts of this research include improved understanding of past climates and improved understanding and prediction of responses of wood growth in western forests to recent or possible future climates. The latter is a significant practical concern, as much of the carbon in forests is stored in wood, and the results of this research will further inform projections of carbon allocation and storage in response to climate change. The project will involve undergraduate researchers in field and lab work and the publication of results. The PIs will engage in outreach both directly through public talks and media interviews as well as through the University of Arizona Extension Service.