Effects of diversity on forest production and wood properties and implications for forest management practices

多样性对森林生产和木材特性的影响以及对森林管理实践的影响

• 批准号: RGPIN-2014-05946
• 负责人: Schneider, Robert
• 金额: $ 1.89万
• 依托单位: Université du Québec à Rimouski
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=681468
• 关键词: Effects; diversity; forest; production; wood

Forest management decisions take many factors into account. One of these factors is how the forest will react to the decision taken in terms of growth. More fundamentally, even if tree growth and development have been studied for over a century, a lot of questions remain on how trees interact. For example, several studies have shown that forests with several tree species can grow more than forests composed by only one of the species. If we can understand why multi-species forests grow better, management practices could be redefined in order to take advantage of the increased growth. Researchers have however only proposed hypotheses to explain these observations, without thoroughly testing them. The long term objective of this research programme is thus to improve management practices in multi-species forests by understanding how trees interact.**Among the ressources used by trees, light is important as it determines the amount of carbon dioxide gas that is transformed into sugars which are used for growth. The amount of light a tree receives is influenced by its neighbours' size and species. For example, the crown of deciduous species such as sugar maple will not intercept light in the same way that evergreen species like balsam fir do. Trees also need nutrients and water that are picked up by the roots, the availability of both which are influenced by the soil processes. These processes are affected by the forest tree composition since the forest litter, made up by tree leafs and other organic material, will differ in nutrient composition between single species forests and multi-species forests. **Within this research programme, the interaction between trees will be studied by looking at both aboveground and belowground dynamics. Using terrestrial laser scanners, which yield high precision 3D information, the interaction between trees will be quantified in order to assess how efficiently trees transform light to biomass growth, and how this efficiency changes from forests with only one species to multi-species forests. Nutrient availability and cycling will also be investigated as to evaluate the differences between single and multi-species forests. The light use efficiency will then be related to soil characteristics in order to fully understand why mixed forests have better growth.*Finally, the growth allocation between each compartment of a tree (e.g. stem, branches, foliage, roots) will also be examined within this programme since the forest industry has historically been interested in the stem of the tree, and not the parts such as the branches, foliage or roots. With the development of other industries such as biofuels and biochemicals using the forest as a supply sources, there will be an increase in the need for knowledge on how much biomass is available from each compartment.**The findings on aerial interactions, soil processes and allocation will be synthesized into a modeling framework based on the metabolic theory of ecology and biomechanics. The theory relates the metabolic rate of an organism to its size. When applied to forest ecosystems, the metabolic theory does not seem to hold. The underlying hypotheses of the theory will be adapted in light of the results obtained from each component of the programme. This adaptation will then be included in a tree growth simulator which will be developed in order to help forest managers take sound decisions when managing multi-species forests. These results will thus help the Canadian forest industry stay competitive. Furthermore, the programme will help to identify the processes which explain why multi-species stands have better growth, and if the increased biomass growth of multi-species stands can lead to increases in forest industry timber supply.

森林管理决定考虑了许多因素。这些因素之一是森林将如何对生长的决定做出反应。从根本上讲，即使已经研究了一个多世纪的树木生长和发育，也有很多关于树木相互作用的问题。例如，几项研究表明，拥有几种树种的森林比仅由其中一个物种构成的森林还要多。如果我们能够理解为什么多物种森林生长更好，则可以重新定义管理实践，以利用增长的增长。但是，研究人员仅提出了假设来解释这些观察结果，而无需对其进行彻底测试。因此，该研究计划的长期目标是通过了解树木的相互作用来改善多物种森林的管理实践。用于生长的糖。一棵树收到的光量受邻居的大小和物种的影响。例如，落叶物种（例如糖枫）的冠无法像诸如Balsam fir一样的常绿物种拦截光。树木还需要树根所吸收的营养和水，这两者都受土壤过程影响。这些过程受到森林树成分的影响，因为树叶和其他有机材料组成的森林垃圾在单个物种森林和多物种森林之间的营养成分会有所不同。 **在该研究计划中，通过查看地上和地下动态，将研究树木之间的相互作用。使用陆地激光扫描仪（产生高精度3D信息），将量化树木之间的相互作用，以评估树木如何有效地转化光线为生物量的生长，以及这种效率如何从只有一个物种的森林变为多物种森林。还将研究营养物的可用性和骑自行车，以评估单物种和多物种森林之间的差异。然后，光的利用效率将与土壤特征有关，以便充分了解混合森林的生长更好。该计划自从历史上对树的茎而不是树枝，叶子或根部等部分感兴趣，既然森林行业一直对树的茎感兴趣。随着其他行业的发展，例如使用森林作为供应源的生物燃料和生化物，将增加有关每个车厢可获得多少生物质的知识的需求。基于生态学和生物力学的代谢理论，分配将合成为建模框架。该理论将有机体的代谢率与其大小有关。当应用于森林生态系统时，代谢理论似乎并不成立。该理论的基本假设将根据程序的每个组成部分获得的结果进行调整。然后，这种适应将包括在树木生长模拟器中，该模拟器将在管理多物种森林时做出明智的决定，以帮助森林经理做出明智的决定。因此，这些结果将有助于加拿大森林行业保持竞争力。此外，该计划将有助于确定流程，以解释为什么多种物种的增长更好，并且如果多种物种的生物量增长增加可能会导致森林行业木材供应的增加。