Data and code for: Adaptive evolution of freezing tolerance in oaks is key to their dominance in North America

Freezing tolerance plays a pivotal role in shaping the distribution and
diversification of organisms across diverse habitats and was likely
crucial to the expansion and adaptive radiation of the American oaks. We
investigated the dynamics of adaptation to climate and potential
trade-offs between stem freezing tolerance and growth rate in 48 Quercus
species from five genus sections grown under temperate and tropical
conditions. Species from colder regions exhibit higher freezing tolerance,
lower growth rates and higher acclimation potential compared to species
from warmer climates, suggesting evolutionary adaptations to seasonal
climate fluctuations. Deciduous species show marked variability in
freezing tolerance across their broad climatic range while evergreen
species, confined to warm climates, display low freezing tolerance. While
annual growth rates are constrained in deciduous species, we found no
direct trade-off between freezing tolerance and growth because deciduous
species that evolved in warm latitudes lost freezing tolerance. Despite an
evolutionary lag, freezing tolerance in Quercus species is closely aligned
with its optimal state. The capacity to withstand cold and adapt to a wide
range of thermal environments was likely critical to adaptive radiation
and current dominance of the North American oaks. Data and code are
provided here.