Modelling the effects of environmental conditions on wood physico-mechanical properties

木材物理力学性质是影响木材结构抗机械性和木质部液流传导性的重要功能性状。木材细胞生产的发展限制，以及优化树木的机械稳定性和水力效率的需要，导致木材特性（即幼龄和成熟木材）的独特径向模式，影响最终产品的性能。然而，环境条件的影响，其潜在的相互作用与造林治疗，对这些模式的变化仍然知之甚少。这项研究计划的长期动机是开发模型，可以帮助理解和预测木材特性的茎内分布，其目的是表征当前森林资源对各种最终用途的适用性，并预测环境条件和造林实践对木材产品流动和价值的影响。基于对木材形成的环境驱动因素的更好理解，我们的目标是产生新一代模型，该模型可以在与森林管理者相关的尺度上预测木材性质的变化。具体来说，我们的目标是：1）了解森林干扰（如火灾）和林分动态对木材特性的影响; 2）量化木材特性对气候变量的响应; 3）扩大从树木年轮到森林景观的层次变化之间的预测。为了实现这一目标，我们的整体方法包括分区的木材性能的变化来源，从细胞壁的规模，树木，林分和森林景观。我们将采用随机抽样方法，检查树木的生长历史，以量化树木所处环境条件的影响。我们将在从北方安大略到纽芬兰的五个地区采集树木样本，这将使我们能够调查北美北方森林的水资源对黑云杉木材性能的影响。木髓到树皮模型将产生木材特性，如密度，尺寸稳定性，强度和刚度，这是木质部结构的生理和最终用途的适用性方面的关键决定因素。这笔赠款将用于资助加拿大缺乏合格人才的一个领域的学生培训。随着森林部门目前从商品生产转向增值生产，人们对使用能够在多个尺度上预测木材质量变化的模型很感兴趣。该计划中开发的模型和软件工具不仅将为我们最新的知识整合提供一个可识别的位置，而且还将有助于在价值链的早期为决策提供信息，从而提高加拿大经济这一重要部门的未来效率。

Wood physico-mechanical properties are key functional traits of trees that influence both their structural resistance to mechanical stimuli and the conductivity of sap in the xylem. Developmental constraints on wood cell production, and the need for optimising both the mechanical stability of trees and their hydraulic efficiency result in distinctive radial patterns of wood properties (i.e. juvenile and mature wood) that influence end-product performance. However, the effects of environmental conditions, and their potential interactions with silvicultural treatments, on these patterns of variation remain poorly understood. The long-term motivation for this research program is to develop models that can help understand and predict the within-stem distribution of wood properties with the aim of characterizing the suitability of the current forest resource for various end-uses and anticipating the impact of environmental conditions and silvicultural practices on wood product flows and value. Based on an improved understanding of the environmental drivers of wood formation, we aim to produce a new generation of models that can predict the variation of wood properties at a scale that is relevant to forest managers. Specifically, we will aim to 1) understand the effects of forest disturbances, such as fire, and stand dynamics on wood properties; 2) quantify the response of wood properties to climatic variables, and 3) scale up predictions between the hierarchical levels of variation, from the tree-ring to forest landscapes. To achieve this, our overall approach consists of partitioning sources of variation in wood properties from the scale of the cell wall to that of trees, stands and forest landscapes. We will use an opportunistic sampling approach whereby we will examine the growth history of trees to quantify the effects of the environmental conditions to which they were exposed. We will sample trees in five regions spanning from Northern Ontario to Newfoundland, which will allow us to investigate the effects of water availability on black spruce wood properties across the North American boreal forest. Pith-to-bark models will be produced of wood properties such as density, dimensional stability, strength and stiffness, which are key determinants of xylem structure both physiologically and in terms of the suitability for end-use. The grant will be used to fund student training in a field which has a shortage of qualified personnel in Canada. With the forest sector currently shifting from commodity to value-added production, there is significant interest in using models that can predict wood quality variation at multiple scales. The models and software tools developed within this program will not only provide an identifiable locus for the integration of our most up-to-date knowledge, but they will also help inform decision-making earlier in the value chain, and thus improve the future efficiency of this important sector for the Canadian economy.