© 1994 Heron Publishing—Victoria, Canada
Adaptation to climatic changes of the timing of bud burst in populations of Pinus sylvestris L. and Picea abies (L.) Karst.
Egbert Beuker
Finnish Forest Research Institute, Punkaharju Research Station, Finlandiantie 18, SF-58450 Punkaharju, Finland / Received October 18, 1993
Summary
To assess the long-term effects of the projected climatic change on Scots pine and Norway spruce in Finland, observations
were made on the timing of bud burst in provenance experiments established in 1931–1932 and in 1978. Significant differences
in the timing of bud burst were found between seed origins. The northernmost origins flushed earlier than origins from southern
regions. However, no correlation was found between the effective temperature sum at which bud burst took place and the annual
mean temperature sum at the original location, probably because the experiments included origins from southerly high-altitude
sites. When the degree days before bud burst in the 1931 and 1978 Norway spruce experiments at Punkaharju were compared, it
appeared that, in the older experiment, the populations had adapted to the environment at the new site as a result of selective
thinning.
Keywords:
Norway spruce, phenology, provenance experiments, Scots pine.
