Western White Pine

Population Genetics

Fig. 1 - Western White Pine
Distribution.

Analyses of AFLP loci discern three metapopulations in western white pine. These include a Pacific Northwest metapopulation that extends from the northern Rockies west to the Pacific and south along the Cascade Mountains to central Oregon. A distinct metapopulation exists in the Siskiyou Mountains of southern Oregon and northern California, and another metapopulation extends into the Sierra Nevada Mountains (Figure 1-A). Like most other pines, western white pine contained moderate to high levels of heterozygosity in all three metapopulations.

Plant-Climate Modeling

Fig. 2 - Whitebark Pine
Distribution.

For western white pine, the contemporary climate space also fits with the current distribution with a small overall error of 3.85 percent. The projected current distribution of western white pine is shown in Figure 1-A. The predicted 2030 climate space for western white pine provides a strong contrast with that of whitebark pine. Western white pine climate space is expected to increase 29 percent by 2030 (Figure 1-B). Overall, suitable climate space for western white pine is expected to increase 157 m in elevation by 2030. This predicted expansion occurs in the northern latitudes, with notable expansion into northwestern Montana and northward into the Canadian Rocky Mountains. In the more southern latitudes of California and southern Oregon, populations are projected to persist at higher elevations. Predicted climate space is reduced in southern Oregon, thereby rendering the projected Sierra Nevada population more disjunct from the southern Cascades.