Complementarity of gymnosperm and angiosperm trees in space and time

裸子植物和被子植物在空间和时间上的互补性

• 批准号: RGPIN-2020-04670
• 负责人: Nock, Charles
• 金额: $ 2.4万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=764528
• 关键词: Complementarity; gymnosperm; angiosperm; trees; space

Forests provide a multitude of essential services to humanity. Forest productivity has long been of interest due to the value of wood as a commodity, and more recently due to the central role of forests in the global carbon cycle. Enhanced productivity of mixtures of tree species, or overyielding, has often been linked to the complementary use of light or nutrients by different tree species possessing different traits or characteristics. In particular, complementarity in mixtures of conifer (evergreen) and deciduous (broadleaf) species has been linked to overyielding in both managed forests and in field experiments. The long-term objective of the proposed research program is to improve our understanding of the relationships among tree diversity, productivity and the resilience of tree growth. In the short-term, existing field experiments will be used to address the following objectives (1) to determine the influence of allometric uncertainty of tree biomass estimation on diversity effects, (2) to quantify the roles of spatial and temporal complementarity for overyielding in tree communities, and, (3) to test how diversity influences the resilience and temporal stability of community productivity. To address (1), allometric equations that relate tree dimensions (diameter, height) to biomass will be developed for each species in a mixture, and how the precision of these equations influence interpretations of selection and complementarity effects will be examined. To address (2) we will quantify complementarity in canopy space by measuring the overlap of tree crowns and then calculating an index of the overlap for the community. We will also extend this index to include temporal complementarity, by also quantifying when tree crowns flush leaves in the spring and shed leaves in the autumn. Finally, we will test if including the flushing and shedding information helps us make better predictions of the growth of functionally diverse tree communities. To address (3), the effects of within-species and between-species competition on the level of tree growth and the variability tree growth will be studied in a long-running experiment with aspen-spruce mixtures. The proposed research will contribute new knowledge to fundamental questions that are central to understanding relationships between tree diversity and forest productivity. Practical knowledge resulting from these studies will help manage forests in the face of stress due to global warming, by informing what stand compositions should be promoted to reduce drought impacts on tree growth.

森林为人类提供多种基本服务。由于木材作为商品的价值，以及最近由于森林在全球碳循环中的核心作用，森林生产力长期以来一直受到关注。混合树种的生产力提高或丰产往往与具有不同性状或特点的不同树种互补利用光照或养分有关。特别是，针叶树（万年青）和落叶（阔叶）物种的混合物的互补性已被链接到管理的森林和实地实验中的丰产。拟议的研究计划的长期目标是提高我们对树木多样性，生产力和树木生长的恢复力之间的关系的理解。在短期内，现有的现场实验将用于解决以下目标：（1）确定异速生长的不确定性的树木生物量估计的多样性效应的影响，（2）量化的空间和时间的互补性的作用，在树木群落的丰产，和（3）测试多样性如何影响社区生产力的恢复力和时间稳定性。为了解决（1），异速生长方程，树木的尺寸（直径，高度）的生物量将开发为每个物种的混合物，以及这些方程的精度如何影响选择和互补效应的解释将被检查。为了解决（2），我们将通过测量树冠的重叠来量化树冠空间的互补性，然后计算群落的重叠指数。我们还将扩展这个指数，包括时间的互补性，也量化时树冠冲洗树叶在春天和秋天落叶。最后，我们将测试包括冲洗和脱落信息是否有助于我们更好地预测功能多样的树木群落的生长。为了解决（3），种内和种间竞争对树木生长水平和树木生长的变异性的影响将在长期运行的实验与白杨云杉混合。拟议的研究将为理解树木多样性和森林生产力之间关系的核心问题提供新的知识。从这些研究中获得的实用知识将有助于在面临全球变暖压力时管理森林，告知应促进何种林分组成以减少干旱对树木生长的影响。