Treesearch

Rocky Mountain bristlecone pine (Pinus aristata Engelm) and limber pine (P. flexilis James) are high-elevation, fiveneedle pines of the southern Rocky Mountains. The pre-settlement role of fire in bristlecone and limber pine forests remains the subject of considerable uncertainty; both species likely experienced a wide range of fire regimes across gradients of site productivity and connectivity of fuels and flammable landscapes. In dense stands and more continuous forests, stand history reconstructions provide evidence for infrequent, high-severity fires. Limber pine can be dispersed long...

Climate changes are projected to profoundly influence vegetation patterns and community compositions, either directly through increased species mortality and shifts in species distributions, or indirectly through disturbance dynamics such as increased wildfire activity and extent, shifting fire regimes, and pathogenesis. High-elevation landscapes have been shown to be particularly sensitive to climatic change and are likely to experience significant impacts under predicted future climate change conditions. Whitebark pine (Pinus albicaulis), a keystone and foundation five-needle pine...

Bark beetle-caused tree mortality in conifer forests affects the quantity and quality of forest fuels and has long been assumed to increase fire hazard and potential fire behavior. In reality, bark beetles and their effects on fuel accumulation and subsequent fire hazard have only recently been described. We have extensively sampled fuels in three conifer forest types (lodgepole pine, Engelmann spruce and Douglas-fir) and described bark beetle/ fuels/fire interactions within the context of intermountain disturbance regimes. Our data sets were developed by measuring the forest biomass in...

Whitebark pine (Pinus albicaulis) is a threatened keystone species in subalpine zones of Western North America that plays a role in watershed dynamics and maintenance of high elevation biodiversity (Schwandt, 2006). Whitebark pine has experienced significant mortality due to white pine blister rust, mountain pine beetle outbreaks and successional replacement possibly due to fire suppression (Schwandt 2006; Smith and others 2008). Current management strategies include letting lightning fires burn or applying prescribed fire to provide habitat for natural seedling establishment or the...

Predicting the future of high-elevation pine populations is closely linked to correctly interpreting their past responses to climatic variability. As a proxy index of climate, dendrochronological records have the advantage of seasonal to annual resolution over multiple centuries to millennia (Bradley 1999). All climate reconstructions rely on the 'uniformity principle' (Camardi 1999), which assumes that modern natural processes have acted similarly in the past, and is used to calibrate proxy records of climate against instrumental observations (National Research Council 2006). The possibili...

The eight white pine species native to the western United States face an array of biotic and abiotic challenges that impact the viability of populations or the species themselves. Well-established programs are already in place to conserve and restore Pinus monticola Dougl. ex D. Don and P. lambertiana Dougl. throughout significant portions of their geographic ranges. More recently, programs have been initiated for the other six species: P. albicaulis Engelm., P. aristata Engelm., P. balfouriana Grev. & Balf., P. flexilis James, P. longaeva D.K. Bailey, and, P. strobiformis Engelm. In...

Analysis of "neutral" molecular markers and "adaptive" quantitative traits are common methods of assessing genetic diversity and population structure. Molecular markers typically reflect the effects of demographic and stochastic processes but are generally assumed to not reflect natural selection. Conversely, quantitative (or "adaptive") traits can be associated with climatic or other environmental variables that drive natural selection, but may not reflect the past demographic processes, such as bottlenecks, post-glacial recolonization, and population isolation. The genetics of whitebark...

The U.S. Forest Service (FS) has been actively working with five-needle pine species for decades. The main focus of this interest has been in restoration efforts involving disease-resistance screening activities in western white (Pinus monticola), sugar (Pinus lambertiana), and eastern white (Pinus strobus) pines in the face of white pine blister rust (WPBR), caused by the non-native invasive pathogen, Cronartium ribicola. There has also been some effort in whitebark pine (Pinus albicaulis) and limber pine (Pinus flexilis) disease-resistance work, but to a lesser degree. Recently the FS...

A three year common garden study was conducted on whitebark pine (Pinus albicaulis) which included 215 families from the eight provenances or seed zones in Oregon and Washington. Total height and needle color were assessed. Height differed significantly among provenances and families, and was primarily associated with source elevation, longitude, and precipitation. A moderate to high heritability was estimated for total height. Seedling needle color differed among provenances and was associated with temperature:moisture indexes and source elevation. Height growth along the Cascade mountain...

We have constructed a consensus genetic linkage map for sugar pine using three mapping populations that segregate for resistance to white pine blister rust, a disease caused by the fungal pathogen Cronartium ribicola. The major gene of resistance, Cr1, was mapped in two of the populations and included in the consensus map, which contains 400 markers organized into 19 linkage groups. All 19 linkage groups align with the 12 linkage groups of the loblolly pine reference map. This work provides the foundation for comparative genomics and mapping within the Pinus subgenus Strobus.