This book is a consideration of the dynamics of forested systems at the time and spatial scales that 1 feel are implied by our present-day use of the term "succession." The investigation will be conducted by exercising a set of ecological models called "gap models," which have been in a state of development and improvement for the past 15 years. It is the intent of this book to use these models as tools for exploring theories of ecological succession. Ecological succession is one of the most obvious and demonstrable features of natural systems when viewed from outside the field of ecology. Succession is used by teachers as a theory that introduces young people to the interactive and dynamic nature of ecosystems. Succession theory and examples of succession are proclaimed from legions of nature trail guidebooks and placards. It is a pleasant classroom exercise to discuss how ecological systems change as the product of internal mechanisms that can be demonstrated by observaaon. The deductive explanation of how a particular place came to have a given assemblage of tree species has a pleasing "Sherlock Holmesian" touch that can be challenging to puzzle through.