Pre Euro-American settlement forest structure and fire regimes for Jeffrey pine-white fir, red fir-western white pine, and lodgepole pine forests were quantified using stumps from trees cut in the 19 th century to establish a baseline reference for ecosystem management in the Lake Tahoe Basin. Contemporary forests varied in different ways compared to the presettlement reference. Contemporary Jeffrey pine-white fir forests have more and smaller trees, more basal area, less structural variability, and trees with a more clumped spatial distribution than presettlement forests. The mean presettlement fire return interval for the period 1450-1850 for Jeffrey pine-white fir forests was 11.5 years, and most fires (>90 percent) burned in the dormant season, while no fire was recorded in the study area after 1871. Differences in the structural characteristics of contemporary and presettlement red fir-western white pine and lodgepole pine forests were similar to those for Jeffrey pine-white fir forests. However, 19 th century logging changed the composition of red fir-western white pine forests, and these forests now have more lodgepole pine than red fir or western white pine. Comparison of contemporary Jeffrey pine-white fir forests with the presettlement reference suggest that restoration treatments should include: (1) density and basal area reduction, primarily of smaller diameter trees, (2) reintroduction of frequent fire as a key regulating disturbance process, and (3) increasing structural heterogeneity by shifting clumped tree distributions to a more random pattern. Restoration treatments in red fir-western white pine forests should include: (1) a shift in species composition by a density and basal area reduction of lodgepole pine, and (2) increasing structural heterogeneity by shifting tree distributions to a more random pattern. In lodgepole pine forests, the restoration emphasis should be: (1) a density and basal area reduction of small diameter trees, and (2) an increase in structural heterogeneity that shifts tree spatial patterns from clumped to a more random distribution. Reintroduction of fire as a regulating process into high elevation red fir-western white pine and lodgepole pine forests may be viewed as a long-term restoration goal.

in North America can be significant – from reduced population sizes to shifts in community structure and diversity (Paillet, 2002; Ellison et al., 2005; Burdon et al., 2006; Lovett et al., 2006; Tomback and Achuff, 2010). Such changes may occur over a few years to decades. Individual- and species-level effects include tree mortality, reduced fecundity and fitness, declining populations, as well as selective pressures on and evolutionary changes in host resistance (Gilbert, 2002; Paillet, 2002; van Mantgem et al., McKinney et al., 2009). Invasive forest pathogens can have both subtle and profound ef-fects on host reproduction, survival, and growth. The introduced fungal pathogen Cronartium ribicola J.C. Fisch. is a primary manage-ment concern in all five-needle white pine ecosystems in western North America. C. ribicola (cause of white pine blister rust; WPBR) was introduced into British Columbia around 1910 and arrived in northern California around 1929, the southern Sierra Nevada by