During the twentieth century, global surface air temperatures rose by 0.8 °C, largely as a result of anthropogenic driven climate change. During the twenty first century, the climate is projected to warm by 2 - 3 °C by 2050, and by as much as 5 °C towards the end of the century. Temperate forests are expected to be susceptible to the effects of warming as their long generations times limit the potential for rapid migration or adaptation.
Reciprocal transplant experiments were used to test populations of Fraxinus excelsior in local and non-local environments to investigate local adaptation across a 2000 km transect of the species natural range. Early results indicate that there is no home site advantage and local adaptation was not found in the populations studied. Phenological observations made in two provenance trials of Fraxinus excelsior revealed that provenances broke bud at different times at a single site, and also at different sites and in different years. Modelling of
the phenological response found that mean spring temperature accounted for more variation than other environmental signals.
Germination testing of Fraxinus excelsior found that the seed from northern provenances required greater chilling to break dormancy than those provenances from further south.
However, the chilling requirement was fully met in all provenances at present.
In summary, this study reveals that provenances of Fraxinus excelsior contain sufficient , genetic variation to cope with medium term climate change through phenotypic plasticity.