Treesearch

The cultivated strawberry is one of the youngest domesticated plants, developed in France in the 1700s from chance hybridization between two western hemisphere octoploid species. However, little is known about the evolution of the species that gave rise to this important fruit crop. Phylogenetic analysis of chloroplast genome sequences of 21 Fragaria species and subspecies resolves the western North American diploid F. vesca subsp. bracteata as sister to the clade of octoploid/decaploid species. No extant tetraploids or hexaploids are directly involved in the maternal ancestry of the...

Adoption of the Northwest Forest Plan (NWFP, USDA and USDI 1993, 1994) in the early 1990s signaled a major shift in forest management on federal lands in western Oregon and Washington. The Plan refl ected composite concerns raised by various resource managers, conservation groups, scientists, and the general public about the sustainability of production-oriented forestry as practiced from the early 1900s. Specifi cally, the plan addressed concerns regarding clearcutting, the harvest of old-growth trees and loss of related habitat, and threats to more than 1,000 potentially sensitive...

We present preliminary results from an experiment in which alternative forest buff er treatments were applied to clusters of watersheds in southwest Washington using a Before-After-Control-Impact (BACI) design. Th e treatments occurred on small (~2- to 9-ha) headwater catchments, and compared continuous fi xed-width buff ered, discontinuous patch-buff ered, and unbuffered streams to an adjacent unlogged reference catchment. Eight treatment clusters were monitored from 2001 to 2006; four were located in the Black Hills (Capitol State Forest) and four in the Willapa Hills of the Coast Range....

Concerns about climate change have generated worldwide interest in managing forests for the uptake and storage of carbon (C). Simultaneously, preserving and enhancing structural, functional, and species diversity in forests remains an important objective. Therefore, understanding tradeoffs and synergies among C storage and sequestration and diversity in managed forests is key to achieving these multiple objectives. Using the experimental framework of the Density Management Study in western Oregon, we examined the relationships among a suite of thinning treatments, above-ground carbon...

Headwater systems, including the channel and the adjacent riparian forest, are a dominant landscape feature in forested watersheds, draining most of the watershed area, and comprising the majority of channel length in drainage networks. Being at the upper extent of watersheds, these systems are smaller and steeper than large streams, and create microhabitats that support diverse instream communities distinct from those in larger streams. Forest management can disturb headwater streams through changes in physical structure, sediment, light, and riparian detrital inputs. Locally, the extent...

Riparian areas are extremely variable and dynamic, and represent some of the most complex terrestrial ecosystems in the world. The high variability within and among riparian areas poses challenges in developing efficient sampling and modeling approaches that accurately quantify riparian forest structure and riparian microclimate. Data from eight stream reaches that are part of the Density Management Study were used in a variety of recent studies that explored sampling and modeling approaches for riparian forest structure and microclimate, and the results are summarized here. When sixteen...

Because forest ecosystems have the capacity to store large quantities of carbon (C), there is interest in managing forests to mitigate elevated CO2 concentrations and associated effects on the global climate. However, some mitigation techniques may contrast with management strategies for other goals, such as maintaining and restoring biodiversity. Forest thinning reduces C storage in the overstory and recruitment of detrital C. These C stores can affect environmental conditions and resource availability in the understory, driving patterns in the distribution of early and late-seral...

We developed an intrinsic potential (IP) model to estimate the potential of streams to provide habitat for spawning fall Chinook salmon (Oncorhynchus tshawytscha) in the Lower Columbia River evolutionarily significant unit. This evolutionarily significant unit is a threatened species, and both fish abundance and distribution are reduced from historical levels. The IP model focuses on geomorphic conditions that lead to the development of a habitat that fish use and includes three geomorphic channel parameters: confinement, width and gradient. We found that the amount of potential habitat...

Peonies (Paeonia), the grand garden perennial of spring and early summer, are economically important to the international cut flower market. Herbaceous peonies (Paeonia section Paeonia), tree peonies (Paeonia section Moutan), and intersectional crosses between the two types (Itoh Paeonia hybrids) are of interest to gardeners, growers, and nursery producers. Thousands of peony cuItivars exist and identity is traditionally determined by experienced horticulturists knowledgeable in plant and bloom characteristics. With DNA extraction possible during any time of the year, molecular markers can...

Over the past two decades the worldwide emergence of the fungal pathogen Batrachochytrium dendrobatidis (Bd), which causes chytridiomycosis, has drastically impacted populations of frogs, toads, and salamanders. Currently, as much as 40% of the roughly 6300 known amphibian species are deemed imperiled, and chytridiomycosis is widely considered the worst infectious disease ever recorded among wildlife. However, a novel online knowledge bank that provides real-time surveillance of the pathogen is now giving amphibian conservationists a powerful tool for curtailing this biodiversity crisis.