Treesearch

Direct seeding is an emerging technique that could significantly reduce the labor and costs associated with whitebark pine (Pinus albicaulis) restoration, and may be compatible with wilderness values. Because other restoration methods-including outplanting of seedlings-are largely incompatible with maintaining wilderness as "untrammeled and natural," the adoption of direct seeding may open an additional 48 percent of whitebark pine habitat to restoration efforts in the future.

Much of the information available on successional modeling for whitebark pine (Pinus albicaulis) communities is based on research conducted in an ecosystem influenced by maritime conditions (Pacific Northwest). The Greater Yellowstone ecosystem (GYE; Wyoming, Montana, and Idaho, USA) is subjected to more continental climatic conditions and as a result, the dynamics of whitebark pine populations in the GYE may in fact be very different from those of maritime populations. Recent survey work in the GYE shows establishment is common with variable recruitment of young trees in the understory of...

In some Rocky Mountain treeline ecotones, whitebark pine (Pinus albicaulis) serves as a tree island initiator more frequently than Engelmann spruce (Picea engelmannii) or subalpine fir (Abies lasiocarpa). Tree island initiation begins with a solitary krummholz tree, which provides sufficient leeward protection so that another tree may become established, resulting in a tree island. More trees may establish on the lee side over time. Whitebark pine mortality from white pine blister rust (pathogen: Cronartium ribicola) reduces opportunities for such facilitation. Will declines in whitebark...

During the naturalization process of white pine blister rust (WPBR, caused by Cronartium ribicola), susceptible pine genotypes will be selected against, along with any traits that are associated with those genotypes, potentially causing a shift in the suite of traits in the post-selection population compared to the native population. Consequently, identifying associated traits with WPBR resistance is critical for effective restoration planning, especially in a changing climate. We sought to determine whether complete resistance to WPBR in limber pine (Pinus flexilis) is associated with...

North America is a secondary center of diversification of the genus Pinus. Most of these speciation events are fairly recent, producing a pattern of widespread shared polymorphism and fuzzy species boundaries. Among five-needle pines, the relationships among Pinus flexilis, Pinus strobiformis, and Pinus ayacahuite have been particularly difficult to determine. To understand the speciation process and the phylogenetic relationships in this species complex, we evaluated genetic and ecological differentiation using multilocus sequence data and ecological niche model comparisons. Our results...

Southwestern white pine (Pinus strobiformis, SWWP) is a component of dry and wet mixed-conifer forests in the southwestern United States and provides ecological function and diversity. The species is geographically limited to Arizona, New Mexico, parts of Texas, southern Colorado, and northern Mexico, but occurs on a wide range of habitats within its distribution. Historically, SWWP regeneration has not been well studied or monitored in mixed-conifer forests of the Southwest, although our understanding of the species’ ecology is increasing. Introductions of Cronartium ribicola, the...

Mountain pine beetle (Dendroctonus ponderosae) and white pine blister rust (causal agent: Cronartium ribicola) are causing extensive crown dieback and mortality in limber pine (Pinus flexilis) in the central and southern Rocky Mountains. Ecologically valuable limber pines often grow in fragile ecosystems where few other trees can grow. The combined effects of mountain pine beetle, white pine blister rust, dwarf mistletoe (Arceuthobium cyanocarpum), and climate change could greatly reduce the biodiversity of these ecosystems. Current status and long-term monitoring of limber pine trees and...

Background The early stage of forest succession following disturbance is characterized by a shift in songbird composition as well as increased avian richness due to increased herbaceous growth in the forest understory. However, regeneration of woody species eventually outcompetes the herbaceous understory, subsequently shifting vegetation communities and decreasing availability of vital foraging and nesting cover for disturbance-dependent birds, ultimately resulting in their displacement. These early stages following forest disturbance, which are declining throughout the eastern United...

The collective U.S. housing market was mixed in February, and once again new single-family (SF) sales were revised sharply downward. SF housing starts were robust, and other housing categories appear to have flat-lined on a monthly basis. Regionally, data were mixed across all sectors. New SF construction and remodeling spending remain positive, increasing at an incremental pace.

The collective U.S. housing market was mixed in March, and new single-family (SF) sales improved positively on a monthly basis. SF housing starts declined on a monthly basis, as well as new SF construction and remodeling spending. Existing house sales were negative on a year-over-year basis. Other housing categories appear to have flat-lined on a monthly basis. Regionally, data were mixed across all sectors.