Connections Between Processes, Transport and Structure

Tree structure forms the physical framework for processes and transport to take place. It also forms the means for the tree to reach towards resources provided by its environment. Thus structure, processes and transport, but also the mechanical stability and long term survival, are strongly interconnected, and the efficiency of whole-tree functioning in terms of energy and raw material use is dependent on how well these components are balanced with each other. Imbalance would be wasteful with respect to both energy and raw material and would result into worse performance in competitive environment. Therefore balanced connections between structure, processes and transport can be assumed to be subjected to strong selective pressures. Since long in botanical literature, number of different observations of regular structural features has been reported (MacCurdy, 2002). A claim can be made that efficient and balanced structures adapted to different environments have emerged in the course of evolution of organisms (see Section 1.2: Basic idea 6).

In this chapter, we review some of the most important interactions between structure, processes and transport from the point of view of understanding whole-tree growth and efficient allocation developed in evolution. We first discuss the functional role of structure in trees, and how it relates to tree growth, and then formulate some connecting principles and present quantitative evidence related to these.