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

模拟环境条件对木材物理机械特性的影响

• 批准号: RGPIN-2017-05891
• 负责人: Achim, Alexis
• 金额: $ 2.84万
• 依托单位: Université Laval
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=643416
• 关键词: Modelling; effects; environmental; conditions; wood

Atmospheric CO2 concentrations and nitrogen (N) deposition rates have increased substantially over the last century due to human activities and are expected to continue unabated. At the same time, forest management practices are also changing, mainly because of an increased necessity for immediate returns on investment. There is thus considerable pressure to understand and predict how tree growth, carbon storage and wood quality will be affected by changes environmental conditions and management practices in the future. Given that wood is the principal merchantable product derived from harvested forests, wood formation is arguably the most economically important process associated with perennial growth in forest trees. This research program is dedicated to developing models that can help predict and understand the within-stem distribution of wood properties, and that can be linked to tree growth simulators to predict the impact of silvicultural practices on wood product flows and value. Over the next five years, the development of our models will focus on obtaining an improved fundamental understanding of the effects of environmental factors on wood physico-mechanical properties. This will be achieved by pursuing three specific objectives: 1) to investigate the effects of climate and the potential interaction with elevated CO2 on wood properties 2) to understand the effects of changes in site characteristics and stand dynamics after major disturbances, such as fires or clearcut, and 3) to test the impact of biomechanical stimuli on the between-tree variation in wood mechanical properties. Wood samples from contrasted growing environments will be used to study the inter-relationships between forest disturbance, tree growth, wood properties, climate and atmospheric conditions. The key species that will be studied are black spruce (Picea mariana) from the boreal forest of Quebec where growth is temperature-limited and 2) loblolly pine (Pinus taeda) trees from the FACE experiment at Duke University in North Carolina exposed to enriched CO2 levels (+200 PPM) for 15 years and Nitrogen fertilisation for 5 years. The radial patterns of variation of different wood properties, such as density, mechanical stiffness and strength, chemical composition and cell dimensions, will be measured on more than 4000 wood discs. The developed models will not only provide a common platform for the integration of our most up-to-date knowledge on the long-term effects of changing environmental conditions on wood structure, they will also help inform decision-making earlier in the forest value chain, and thus improve the future efficiency of this important sector for the Canadian economy.

大气二氧化碳浓度和氮（N）沉积率在上个世纪由于人类活动而大大提高，预计将继续不减弱。同时，森林管理实践也在发生变化，这主要是因为立即获得投资回报的必要性增加。因此，有很大的压力来理解和预测将来环境条件和管理实践的变化将如何影响树木生长，碳储存和木材质量。鉴于木材是源自收获森林的主要商品产品，因此木材形成可以说是与林木多年生生长相关的最重要的过程。该研究计划致力于开发可以帮助预测和理解木质特性的茎内分布的模型，并且可以与树木生长模拟器相关联，以预测造林实践对木材产品流和价值的影响。在接下来的五年中，我们的模型的发展将集中于对环境因素对木材物理机械特性的影响的基本了解。这将通过追求三个特定目标来实现：1）研究气候的影响以及与二氧化碳对木材特性的潜在相互作用2）了解现场特征变化和重大干扰后的动态变化的影响，例如火灾或清晰度和3）测试生物力学刺激对木材机械性能中树间变化的影响。对比增长环境中的木材样本将用于研究森林干扰，树木生长，木质特性，气候和大气条件之间的相互关系。将要研究的关键物种是魁北克北方森林中的黑云杉（Picea Mariana），那里的生长是温度限制的，2）北卡罗来纳州杜克大学的脸部实验中的Loblolly Pine（Pinus taeda）树木暴露于富集的CO2 15年的水平（+200 ppm）和5年的氮肥。不同木材特性的变化的径向模式，例如密度，机械刚度和强度，化学成分和细胞尺寸，将在4000多个木盘上测量。开发的模型不仅将为整合我们关于改变环境条件对木材结构的长期影响的最新知识的共同平台，而且还将帮助较早的森林价值链中的决策告知决策，从而提高了这一重要部门对加拿大经济的未来效率。