PhD defence: Brynjar Skúlason – Københavns Universitet

Videresend til en ven Resize Print kalender-ikon Bookmark and Share

IGN > Ph.d.-forsvar > 2017 > PhD defence: Brynjar S...

PhD defence: Brynjar Skúlason

Brynjar Skúlason defends his thesis,

Provenance variation in subalpine fir grown as an exotic tree species in Denmark and Iceland

Supervisor:
Senior Researcher Ulrik Bräuner Nielsen, Department of Geosciences and Natural Resource Management

Assessment Committee:
Professor John Frampton, North Carolina State University
Research Leader Bo Karlsson, Skogforsk (Forestry Research Institute of Sweden)
Senior Researcher Jon Kehlet Hansen (chair), Department of Geosciences and Natural Resource Management

Summary:
In Denmark and Iceland, there has been increasing interest in the use of subalpine fir (Abies lasiocarpa (Hook.) Nutt.) as an exotic species; in Denmark as a niche product for the Christmas tree market and in Iceland as the main Christmas tree species. A field test with 26 provenances of subalpine fir (A. lasiocarpa var. lasiocarpa) and corkbark fir (A. lasiocarpa var. arizonica (Merriam) Lemmon) was established at three sites in Denmark and at one site in Iceland in 1999. Adaptability, Christmas tree quality, growth rhythm and susceptibility to pests and pathogens were measured and assessed in a period of 15 growing seasons after establishment. Provenances showed significant differences for all measured traits. The northernmost provenances showed earliest bud set, highest autumn frost tolerance and a latitudinal cline was delineated, while the southernmost provenances showed earliest flushing and the most spring frost damage on buds. The westernmost subalpine fir provenances from Washington state and British Columbia showed the overall best results in Denmark, with the highest survival (after 15 years), fastest height growth and highest Christmas tree quality and profitability, as well as both good postharvest needle retention and high resistance to pests. The corkbark fir provenances also showed high Christmas tree quality and the lowest frequency of fork formation. However, corkbark fir provenances also exhibited the poorest postharvest needle retention and were very susceptible to the fungus Neonectria neomacrospora in Denmark. In Iceland the corkbark fir showed superior results, especially for survival rate and Christmas tree quality. The White River provenance from British Columbia is recommended for use in Denmark. The Mount Taylor provenance from the Cibola National Forest in New Mexico is recommended for use in Iceland. Any recommendation for Iceland must be revised if Neonectria neomacrospora or other new pests migrate to the country. Based on these results, establishment of clonal seed orchards with subalpine fir have been initiated in both countries.

The thesis is available for inspection at the PhD administration office, 03.1.353, at Øster Voldgade 10