Collaborative Research: P2C2--Does Liebig's Law Allow for Capturing More Signal from the Forest?

本项目旨在开发和应用树木生长模型，以加强树木年轮宽度记录的气候信号（温度和湿度）的恢复。这种树木生长模式具有改善大规模气候重建的潜力，并将有助于理解和改善仪器和树木年轮气候重建之间的系统差异。生长模型基于李比希最小定律，该定律描述了树木的生长如何受到最具限制性因素（如阳光、营养、水分）的支配。研究人员将：1)对来自国际树木年轮数据库的4213个树木年轮站点进行全面分析，以了解李比希定律如何影响林内变异；2)描述李比希定律在模式和观测环境下影响树木间气候信号分布的方式。该项目的目标是发展重建技术，在存在局部生长限制的情况下，反演温度或降水的生长。这些重建技术有可能大大改善局部和区域气候变率的重建。潜在的更广泛的影响包括使用树木生长和树木年轮代用物进行气候重建的新方法。将为旧金山州立大学（教育部指定的少数民族服务机构）的一年级学生开设一门基于野外的树木气候学课程，目的是招收少数民族和经济条件较差的学生学习地球科学。该项目将支持两名研究生的教育和培训。研究人员将把这个项目的概念和结果纳入他们各自的课程和外展活动中。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project aims to develop and apply a tree growth model in order to strengthen the recovery of climate signals (temperature and moisture) recorded in the width of tree-ring. This tree growth model has the potential to improve large-scale climate reconstructions and will be useful for understanding and ameliorating systematic differences between instrumental and tree-ring climate reconstructions. The growth model is based on the Liebig's law of the minimum which describes how tree growth is dictated by the most limiting factor (e.g. sunlight, nutrients, moisture). The researchers will: 1) conduct a comprehensive analysis of 4,213 tree-ring sites from the International Tree Ring Data Bank to understand how Liebig's Law influences within-stand variability; and 2) characterize the ways that Liebig's Law influences the distribution of climate signal across trees in both a model and observational context. The goal of this project is to develop reconstruction techniques for inverting growth for temperature or precipitation in the presence of local limitations on growth. These reconstruction techniques have the potential to result in substantially improved reconstructions of local and regional climate variability. The potential Broader Impacts include new methodologies to use tree growth and tree-ring proxies for climate reconstructions. A dendroclimatology field-based class to first-year students at San Francisco State University (a designated Minority Serving Institution by the Department of Education) will be developed, with the goal of recruiting minority and economically disadvantaged students to the Earth Sciences. The project will support the education and training of two graduate students. The researchers will incorporate concepts and results from this project in their respective classes and outreach activities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.