Tree Responses to Environmental Cues

Trees use environmental cues such as drought, temperature and light to synchronize growth and development with seasonal changes, and to compete for resources with other plants. The ability of trees to effectively sense and respond to these signals requires molecular programs to enable them to track change rapidly and adapt accordingly. Advances in genomics, transcriptomics and metabolomics have improved our understanding, but there are still considerable gaps and for trees in particular. This chapter reviews recent advances in understanding tree responses to episodes of drought, elevated temperature, low temperature and photoperiod, because these cues are amongst the most important environmental factors affecting tree performance over the course of the season and in a changing climate. For example, trees are expected to suffer more from extreme low temperature events during winter or increased frequency of heat waves during summer and, in many regions, from longer periods of drought. In addition, elevated temperature is expected to extend the length of the growing season, while responses to photoperiod might constrain positive responses to warmer spring or autumn. Finally, the interaction of multiple cues is reviewed and emerging areas of research are discussed such as the role of natural variation, adaptation, plasticity and epigenetics.