ABSTRACT
Temperate perennials, such as trees, must have a physiological mechanism for anticipating seasonal changes in order to enter dormancy prior to winter and resume growth in the spring. Proper timing of the onset and release of dormancy impacts the productivity, survival, and spatial distribution of temperate perennials. Models of continued global warming (Serreze et al. 2000) and climate change predict that temperate regions will experience the greatest changes in winter temperature (IPGC 1997). This increase in winter temperature will cause delayed and erratic fl ower development in tree species with a large chilling requirement, as well as early spring bud break and an increased risk of frost damage in species with low chilling requirements (Heide 2003). In addition, anticipated north/south plant migration in response to changing temperatures will challenge ecotypes because this movement also imposes different seasonal daylengths. Dormancy also plays a critical role in determining the degree to which invasive perennials survive the winter and thus these changes may also affect agricultural productivity and ecosystem biodiversity.
