Treesearch

Fusarium species can cause damping-off and root rot of young conifer seedlings, resulting in severe crop and economic losses in forest nurseries. Disease control within tree nurseries is difficult because of the inability to characterize and quantify Fusarium spp. populations with regard to disease potential because of high variability in isolate virulence. Fusarium isolates were collected from healthy and diseased seedlings of Douglas-fir (Pseudotsuga menziesii) and western white pine (Pinus monticola) from a nursery in Idaho, USA. Molecular markers such as DNA sequences (mitochondrial...

Abies religiosa (HBK) Schl. & Cham. (oyamel fir) is distributed in conifer-dominated mountain forests at high altitudes along the Trans-Mexican Volcanic Belt. This fir is the preferred host for overwintering monarch butterfly (Danaus plexippus) migratory populations which habitually congregate within a few stands now located inside a Monarch Butterfly Biosphere Reserve. Our objectives were to predict and map the climatic niche for A. religiosa for contemporary and future (2030, 2060 and 2090) climates, suggest management strategies to accommodate climate changes, and discuss implications...

Under projected changes in global climate, the growth and survival of existing forests will depend on their ability to adjust physiologically in response to environmental change. Quantifying their capacity to adjust and whether the response is species- or population-specific is important to guide forest management strategies. New analyses of historic provenance tests data are yielding relevant insights about these responses. Yet, differences between the objectives used to design the experiments and current objectives impose limitations to what can be learned from them. Our objectives are...

Species of the fungal genus Armillaria are pervasive in forest soils and are associated with widely ranging tree species of diverse forests worldwide (Baumgartner et al., 2011). As primary decay drivers of ecosystem processes, Armillaria species exhibit diverse ecological behaviors, ranging from virulent root and/or butt pathogens of diverse woody hosts, such as timber, fruit, nut, and ornamental trees, beneficial saprophytes, or mycorrhizal associates of orchids (Baumgartner et al., 2011). Furthermore, genets of Armillaria spp. are recognized as being among the oldest and longest lived...

When the National Park Service was established in 1916, the new agency inherited an architectural legacy developed by private interests, particularly the railroads. This legacy included Northern Pacific's Old Faithful Inn in Yellowstone and Santa Fe's El Tovar at the south rim of the Grand Canyon, both built in the Swiss Chalet­Norway Villa tradition. This historical precedent - borrowing attractive yet incongruous design themes from the Old World with little regard for the natural setting - was inherited by the designers of the structures at Colorado's Mesa Verde National Park. Yet,...

During periods with epidemic mountain pine beetle (Dendroctonus ponderosae Hopkins) populations in lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) forests, large amounts of tree foliage are thought to undergo changes in moisture content and chemistry brought about by tree decline and death. However, many of the presumed changes have yet to be quantified. In this study, we quantified and compared fuel moisture, chemistry, and resulting flammability of bark beetle affected foliage in terms of ignitability, combustibility, consumability, and sustainability at a site in...

On the basis of reports in the literature, incidence of dystocia in wild elk (Cervus elaphus) across the west is rare. In 2011, one of 34 (3%) pregnant cow elk in our study experienced dystocia during birth. Our visual observations indicated that it took approximately 4 days for a radio-collared cow elk to succumb to dystocia in our study. Little is known about dystocia in wild elk populations, and our observation provides some insight about fetal malpresentations.

Electrofishing-based estimates of fish abundance are common. Most population models assume that samples are drawn froma closed population, but population closure is sometimes difficult to achieve. Consequently, we individually electrofished 103 radio-tagged trout of two species, westslope cutthroat trout Oncorhynchus clarkii lewisi and brook trout Salvelinus fontinalis, in five streams in western Montana to quantify the influence of habitat and fish size on capture efficiency and movement related to electrofishing with unpulsed DC. First-pass capture efficiency was 46% and declined on...

Native Americans relied on fire to maintain a cultural landscape that sustained their lifeways for thousands of years. Within the past 100 years, however, policies of fire exclusion have disrupted ecological processes, elevating risk of wildfire, insects, and disease, affecting the health and availability of resources on which the tribes depend. On Indian Reservations, tribal forest plans include prescribed fire to restore and maintain the lands. Public land managers are now considering ways to restore the fire-based ecosystem, but tribal knowledge about the use and effects of fire has...

Landscape-level bark beetle (Coleoptera: Curculionidae, Scolytinae) outbreaks occurred in Arizona ponderosa pine (Pinus ponderosa Dougl. ex Law.) forests from 2001 to 2003 in response to severe drought and suitable forest conditions.We quantified surface fuel loadings and depths, and calculated canopy fuels based on forest structure attributes in 60 plots established 5 years previously on five national forests. Half of the plots we sampled in 2007 had bark beetle-caused pine mortality and half did not have mortality. Adjusting for differences in pre-outbreak stand density, plots with...