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

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。

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.