Damage by pathogens and insects to Scots pine and lodgepole pine 25 years after reciprocal plantings in Canada and Sweden

ABSTRACT

A combined species – provenance – family experiment with Scots pine and lodgepole pine was planted in Canada and Sweden. One aim of the experiment was to evaluate the two species’ sensitivities to pathogens and insects 25 years after establishment in their non-native continents. In Canada, Scots pine had better average survival than lodgepole pine, but survival rates among trees from the best seed-lots were equal. In Canada only western gall rust infected Scots pine to some extent, and mountain pine beetles attacked and killed Scots pine more frequently than lodgepole pine. At one site in Sweden, lodgepole pine had higher survival rates than Scots pine, whether evaluated as an overall average or with data from only the best surviving seed-lots. At the other Swedish site, the species’ survival rates were equal, largely since moose damage was much more frequent on lodgepole pine than on Scots pine. Adaptation to local conditions seemed to be important in the resistance of stem breakage caused by heavy snowfalls. The exotic species generally seemed to resist the new threats, but more serious damage by mountain pine beetle on Scots pine than on lodgepole pine in Canada demonstrates possible drawbacks when using exotic species which are phylogenetically similar to native.

KEYWORDS:

• Exotic species
• western gall rust
• mountain pine beetle
• rust fungi
• stem breakage
• stability
• heritability

Acknowledgements

The experiment was initiated by the late Professor and Chief Silviculturalist at SCA (Svenska Cellulosa Aktiebolaget), Stig Hagner, and inspired by the Professor in forest pathology at the Swedish University of Agricultural Sciences (SLU), Margareta Karlman, the Professor in forest genetics at SLU, Dag Lindgren and the late Professor Oscar Sziklai at the University of British Columbia, Canada. Many individuals and organizations have supported and contributed to the experiment: Bart Van der Kamp, Per Persson, Christian Walli (Balco Forest Industries Ltd.), Canadian Forest Products Ltd and TimberWest Forest Ltd. Research scientists Nicholas Ukrainetz, Michael Carlson and Richard Reich, and Future Forest Ltd in Canada offered much support for the work in Canada. The author acknowledges all those forces that enabled the study and also Professor Björn Elfving and Nicholas Ukrainetz for contributions in data analyses, and Per Hansson for data collection in Sweden and important comments.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Bo Rydins Stiftelse för Vetenskaplig Forskning, Sweden [grant number F06/09].