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

树木年轮是过去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。这些知识上的空白与构成木材的组织的基本自然历史有关。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的使用的科学基础，这些数据集包括每年何时开始关键的树木生长过程，每个过程进行的速度和持续时间，以及气候条件的每日到季节变化与每个过程的时间、速度和大小相关的程度。这将是美国西部的第一次这样的研究。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，所有这些地点都以现有的通量塔设施为中心，包括这一大片地区树种气候学中使用的主要树种。然后，他们将把树木生长数据与空气、树干和土壤温度、水分可获得性、气流和其他因素以及枝条伸长和针叶伸长等物候事件进行比较。这些数据和比较对于改进树木年轮生长控制的正演模型是必不可少的。这些方法基于合理的年轮气候控制过程模型，具有提高稳健性、扩展普适性和更好地评估基于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改善对过去气候的理解，以及改善对西部森林木材生长对最近或可能的未来气候的反应的理解和预测。后者是一个重大的实际问题，因为森林中的大部分碳储存在木材中，这项研究的结果将进一步为应对气候变化的碳分配和储存预测提供信息。该项目将让本科生研究人员参与现场和实验室工作，并发布结果。私人投资机构将直接通过公开谈话和媒体采访以及通过亚利桑那大学推广服务处开展外联活动。

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.