FOREST SUCCESSION AND GAP DYNAMICS

In this chapter, we review forest successional processes at a global scale covering forests in tropical, subtropical, temperate and boreal regions. The chapter provides a brief history of the concept, discussing the contributions of authors such as Gleason, Clements and Watt. Historical treatment of the topic sets the stage for an overview of common themes in forest succession. Themes include compositional and structural change; mechanisms of succession such as facilitation, tolerance and competition; the relationship of succession to diversity; and the importance of stochastic processes, complexity and disturbance interactions. Gap dynamics are covered for those forests where they are an integral aspect of succession. We explore the role of gaps and gap size in creating a mosaic of resource availability for light, water and nutrients, which help maintain diversity by allowing mid-tolerant species to persist, as well as allowing shade-tolerant species accession to the canopy. Finally, we address challenges associated with global change.