Climate change and forest insect pests

Climate change and the underlying causal factors have been thoroughly described in the scientific literature. Although well understood and documented in general, we are only beginning to understand the effects of climate change on biotic systems, such as insect communities. It seems obvious that insect pest problems should be be more important in a warmer climate; temperature has a strong impact on insect physiology and demography. It must be remembered, however, that insect distribution and abundance are controlled by many factors other than temperature, e.g. host plant, natural enemies. This chapter summarizes empirical evidence for climate change-induced insect pest problems, i.e. changed distribution range and frequency of insect outbreaks. The chapter reviews cases of forest pests for which there is sufficient scientific evidence of climate change-effects on their population dynamics leading to outbreaks, strong enough to be a concern for forest ecology and management.