- Department of Forest Economics, Swedish University of Agricultural Sciences
The annual rhythm and height of 21-year-old trees was registered over two consecutive years in three provenance field tests in central Sweden. The rhythm of approx. 200 trees from each of four provenances was characterized by the pattern of needle elongation and the changes in bark colour of terminals. Correlation, regression and multiple discriminant analyses revealed a strong relationship between origin and annual rhythm but exhibited at the same time a large intra-provenance variation. It was shown that disharmony between the rhythm of the tree and the external climate results in a decrease of growth. The variation within a stand progeny was found to be so large that, irrespective of planting site, there were some trees that were genetically unfit for the climate. Selection in the nursery may decrease this heterogeneity. It was shown how the regression of height on rhythm among trees within a population may be used in tree breeding to asses plasticity, degree of adaptation to the test site, and potential growth capacity in different environments.
provenance; field tests; annual rhythm; growth; Pinus silvestris
Studia Forestalia Suecica