Chapter One - Forests and global change: an overview

Summary

Introduction

Forests provide a range of goods and services upon which humanity depends, from local (e.g. flood prevention) to global (e.g. carbon sequestration). Yet some 13 Mha of forest is lost each year, mostly in the tropics (Canadell & Raupach 2008). Considerable political, media and scientific attention has focused on this forest destruction and fragmentation and its implications for livelihoods, biodiversity and ecosystem services. However, human influences on forests now go beyond deforestation and degradation, to changing the states of atmosphere and climates and altering biogeochemical cycles, which in turn bear heavily on the functioning and composition of forest ecosystems. A range of disciplines are required to chart such change, understand how it works and predict where it is going. They span a broad range of scales from photosynthetic machinery in leaves, to the dynamics of forests across wide regions, to global atmospheric circulation. Integration of these multiple strands and scales of investigation has only recently begun, and this volume makes an important contribution to weaving them together into a more cohesive, albeit still incomplete, picture.

The story is told in three parts, beginning with a collection of perspectives on the global environmental drivers of forest change, the complexity of their interaction and effects, and important feedbacks. The second section concentrates on species-level traits and trade-offs, and how these explain the composition and dynamics of forests in a changing world. Finally, a number of approaches and tools are presented for measuring forest change and forecasting its future direction.