Because climate has the greatest effect in determining the genetic structure of forest tree species, climatic variables with large effects on growth and survival need to be identified. This would enable proper matching of tree populations to planting sites in the present and future climates. We analysed 24-year survival (S24), height (H24) and diameter (D24) from a series of white spruce provenance trials with 46 populations and 8 test sites in Alberta, Canada. We determined: (1) the amount and pattern of genetic variation, (2) the response of populations to climatic transfer and (3) the potential effects of climate change (2030-2039) on H24 and S24 of the species in Alberta. We found that: (1) using the intraclass correlation, the between-population genetic variance was 10.6% (H24) and 6.6% (D24) of the betweenpopulation phenotypic variance across sites, (2) three climatic white spruce regions exist in Alberta within which variation in growth potential is strongly clinal, (3) the annual moisture index (AMI) expressed as a ratio of degree days above 5°C (GDD) and mean annual precipitation (MAP) was the major determinant of survival and growth at the test sites, (4) we found that at the level of AMI predicted for the 2030-2039 period, survival and growth would decline substantially in the continental part (northern and central) of Alberta where drought already exists. However, during the same period, survival and growth would increase substantially in the foothills and Rocky Mountains region where growth is currently limited by low GDD due to a short growing season.

Growth and survival of 33 populations from a species complex involving interior lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and jack pine ( Pinus banksiana Lamb.) and their natural hybrids in Alberta were evaluated at ages 5, 10, and 15 years in eight test sites across Alberta. We determined population differentiations by estimating Mahalanobis distances between populations from the canonical discriminant analysis of the total variability and by calculating dissimilarity indexes between populations from the quadratic regression of overall growth and survival on the overall climate. The grouping of the populations based on the Mahalanobis distances showed that most jack pine populations could be separated from lodgepole and hybrid populations, but no further subdivision was possible to distinguish lodgepole from hybrid populations. This clustering pattern was remarkably similar to the grouping based on molecular markers as shown in our earlier study. This pattern of grouping is best explained by a clear elevational demarcation between jack pine at low elevations and lodgepole pine and hybrids at midrange and high elevations. The grouping of the populations based on the dissimilarity indexes revealed a somewhat contrasting pattern; most lodgepole pine populations were in one group, whereas jack pine and hybrid populations were mixed up in the other group. The two contrasting patterns of grouping suggest that nonclimatic factors such as edaphic preference and habitat disturbances are also important in determining population distributions and niche spaces in the lodgepole – jack pine complex.

Pinus resinosa displays a rather uniform phenotype over a relatively small geographic distribution with a 9-degree latitudinal spread. DNA quantity per cell from 20 seed sources collected throughout the growing range varied significantly by a factor of 2.2 from the lowest to the highest amount. A south-to-north increasing DNA gradient was not observed as reported previously for other members of the Pinaceae.

Embryos and megagametophytes of open-pollinated seed of 37 white spruce (Piceaglauca (Moench) Voss) trees from a seed production area were analyzed by starch gel electrophoresis to determine the genetic structure and mating system over 2 seed crop years. Analysis of four polymorphic enzyme loci (Gdh, Idh, Pgm, and Pgi-2) for spatial and temporal genetic structure and mating system indicated substantial deviations from the random mating model that is assumed when open-pollinated families are designated as half-sibs.