Data from: Variation in seed traits, leaf phenology and growth performance among sessile oak provenances from Baden-Württemberg and Alsace

Given the long lifespan of forest trees, their adaptation to climate
change may lag behind the pace of global warming. In this context, it is
crucial to explore the variation of fitness-related traits. Our study
focuses on assessing the adaptive potential of sessile oak (Quercus
petraea), specifically concerning seed characteristics, as well as leaf
phenology and growth performance of seedlings. To investigate this, we
conducted a common garden experiment in the field using seeds sampled from
15 relict and four regularly managed sessile oak provenances in
Baden-Wuerttemberg, Germany, and Alsace, France. In particular, we
collected data of 57 open-pollinated families originating from 12
provenances (mostly 5 families per provenance, one case with 3 and one
with 4 provenances). For the remaining 7 provenances, we used bulked seeds
for the field trial. We assessed seed weight and germination rate, height
in the first and second growth year (2021 and 2022, respectively), as well
as budburst and leaf senescence in the second year (2022). We observed
differences in budburst, with the provenances from higher altitude as well
as from the Franconian Plateau (in Germany) flushing up to three days
later than the provenances from lower altitudes in the other regions. We
interpret this phenological behaviour as the result of adaptation to late
frosts, which are more common in cold regions. Additionally, we found
significant variation in seedling height. These findings highlight
adaptive genetic processes in sessile oak populations and underscore the
importance of preserving their genetic diversity as a valuable resource
for future adaptation to climate change. Such adaptive differentiation
should also be considered in seed sourcing. Taking climate change into
account, forest reproductive material originating from colder parts of a
provenance region should preferably be used locally and ideally enriched
with provenances from lower altitude.