Structure

Abstract

The scope of our considerations in the present book covers a wide area from subcellular plant parts to a global vegetation zone, in particular the boreal forest. There are, however, natural hierarchical levels in the structure which are necessary to understand in the study of natural phenomena in such a zone. The hierarchical structure we will describe here will be utilized later in our discussion in Chapters 7–10. A central challenge in ecology and forest growth studies is to understand the emergence of ecosystem behavior from the interaction of its components. For example, a forest stand can be regarded as an assemblage consisting of living organisms, especially trees, their organs and ultimately molecules at different levels of structural hierarchy. Since evolutionary selection mechanisms act upon individual organisms, these organisms are the basic building blocks of any ecosystem. The success of an individual organism in dealing with its environment determines its capacity to survive and spread its off-spring. Individuals have to accomplish multiple tasks such as photosynthesis, nutrient and water uptake, water transport, growth and mechanical support. Specialized organs (vegetative or reproductive) have developed to perform these tasks. For example, leaves perform photosynthesis, fine roots take up water and nutrients, and stems transport water and assimilates. All organs include several tissues, involved in specialized functions within the organ.