The role of root grafting in competitive/cooperative relationships between trees

根嫁接在树木竞争/合作关系中的作用

• 批准号: RGPIN-2017-05532
• 负责人: Desrochers, Annie
• 金额: $ 2.33万
• 依托单位: Université du Québec en Abitibi-Témiscamingue
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711457
• 关键词: role; root; grafting; competitive; cooperative

Natural root grafting (anastomosis) challenges the notion of plant individuality and the consideration of forests as groups of individual trees competing with each other for resources. The sharing of substances (e.g. water, sugars) between trees, allows for cooperative relationships to occur. The long term objective of this research program is to demonstrate the ecological significance of root grafting. In the short term, I want to answer the following question: are root-grafted trees better competitors? First, occurrence, timing and effect of spacing on root grafting will be assessed in monospecific plantations of hybrid poplar, white and Norway spruce. Root grafts will be collected and brought to the lab for dendrochronological analysis. Size and age of roots at grafting, and distance between grafted trees will be determined and linked to root grafting frequency and timing. Then, using densely planted plots, inter- vs intraspecific competition/facilitation relationships will be evaluated in mixed-species plots in relation to root grafting. Relationships between trees will be characterized using distance-dependent and independent competition indices. Using dendrochronology techniques, timing of root grafting will be determined and linked with chronological competition index values throughout the lifespan of the stands. This will enable us to determine if stand development exhibited a predictable time-sequence spatial pattern resulting from competition for resources or if root grafting stalled stand development by allowing trees to respond (and compete) as a group rather than as individual stems. The different spacings and mixed species plantations will also allow us to examine stand development sequence to see if competition forces act as a trigger for root grafts to form between neighboring trees. Ecological significance of root grafting forces us to reconsider traditional forest stand dynamics concepts such as competition, dominance and succession, concepts on which modern forestry is based on. The proposed research will throw light on the role that root grafting plays in tree-to-tree interactions during stand evolution by looking at stand-level grafting in plantations and in balsam fir natural forests. So far, my research has shown a general positive impact of root grafting on growth of connected trees, and suggests that grafted groups of trees benefit from each other to confront stress. From an applied perspective, few practitioners have associated successful or unsuccessful silvicultural operations to root connections. For example, it is often said that some suppressed trees are unable to respond to thinning (reduced competition), while the answer lies in skewed root-shoot ratios created by reducing leaf area of stands sharing communal root systems. Our work in plantations thus has the potential to impact how intensively managed plantations are established.

自然根嫁接（吻合）挑战了植物个体性的概念，也挑战了将森林视为相互竞争资源的单个树木群体的观点。树木之间的物质（如水，糖）共享，允许合作关系的发生。这项研究计划的长期目标是证明根嫁接的生态意义。在短期内，我想回答以下问题：根嫁接树更好的竞争对手？首先，发生，时间和间距对根嫁接的影响将在杂交白杨，白色和挪威云杉单种人工林进行评估。根移植将被收集并带到实验室进行树木年代学分析。嫁接时根的大小和年龄以及嫁接树之间的距离将被确定，并与根嫁接频率和时间相关联。然后，使用密集种植的地块，种内与种间竞争/促进关系将在混合种地块进行评估，根嫁接。树木之间的关系将使用距离依赖和独立的竞争指数的特点。使用树木年代学技术，根嫁接的时间将被确定，并与时间竞争指数值在整个生命周期的立场。这将使我们能够确定，如果林分发展表现出可预测的时间序列的空间格局，导致资源的竞争，或者如果根嫁接停止林分发展，让树木响应（和竞争）作为一个群体，而不是作为个人的茎。不同的间距和混合物种的种植园也将使我们能够检查林分的发展顺序，看看竞争力是否作为一个触发器的根嫁接形成相邻的树木之间。 根嫁接的生态学意义迫使我们重新考虑传统的林分动态概念，如竞争，优势和演替，现代林业的基础上的概念，拟议的研究将通过观察人工林和香脂冷杉天然林的林分水平嫁接，揭示根嫁接在林分进化过程中树与树的相互作用中所起的作用。到目前为止，我的研究已经表明，根嫁接对相连树木的生长有着普遍的积极影响，并表明嫁接的树木群体在面对压力时相互受益。从应用的角度来看，很少有从业者将成功或不成功的造林作业与根联系联系起来。例如，人们常说，一些被抑制的树木无法应对间伐（减少竞争），而答案在于通过减少共享公共根系的林分的叶面积而产生的倾斜的根冠比。因此，我们在种植园的工作有可能影响如何建立集约管理的种植园。