Seed transfer and climate change effects on radial growth of jack pine populations in a common garden in Petawawa, Ontario, Canada

The effects of seed transfer and climate change on the width and basal area of tree rings were studied in 21 provenances of jack pine (Pinus banksiana Lamb.) grown in a common-garden plantation in Petawawa, Ontario, Canada. Seed-source origin significantly influenced both mean tree-ring width and mean annual basal area increment over a 25-year growth period (1975-1999). Temperature and precipitation transfer functions were developed to predict width and basal area of tree rings of the jack pine populations. The best predictors of growth were the transfer distances of mean annual maximum daily temperature and annual precipitation between the plantation site and the seed origins. Radial growth of the jack pine populations was mainly related to temperature at seed origin and, to a lesser degree, to precipitation at seed origin. Extension of the transfer functions to three sets of independent data revealed significant correlations between estimated and predicted mean radial growth characteristics. Seed sources of jack pine originating from warmer and drier climates than that of the plantation site in Petawawa had slightly higher mean ring widths and basal areas than the local populations. The application of different climate change scenarios derived from general circulation models to the developed transfer functions indicated that radial growth of jack pine may decline only if significant climate changes occur, which might not happen before the mid 21st century. Both a higher radial growth of southern seed sources and a potential negative effect of a significant temperature increase and precipitation decrease in future suggest restricting the northward transfer of southern seed sources to less than 1° latitude. However, provenance specific differences in survivorship, frost- and disease-resistance, and cone serotiny should also be taken into consideration.