Treesearch

Seed shatter dates for antelope bitterbrush were estimated from collections at 192 sites in Oregon and surrounding states. Shatter date was strongly correlated to elevation, and an equation that included elevation, latitude, longitude, and longitude squared explained 79 percent of the variation in seed shatter dates. This information can assist those needing to schedule seed collection activities at multiple locations.

Clavulina lilliputiana, found growing in troops on a road bank in Tasmania, differs from other species of the genus by its combination of very small size (mostly < 1 cm tall), unbranched but often lobed form, cerebriform surface, and basidia up to 100 µm long.

The annual return of spawning Pacific salmon (genus Oncorhynchus) can have a dramatic effect on the nutrient budgets of recipient freshwater ecosystems. We examined how spawning salmon affect streamwater concentrations of inorganic nitrogen and phosphorus and dissolved organic carbon (DOC) in Peterson Creek, a salmon stream in southeast Alaska. In the presence of spawning salmon, concentrations of ammonium (NH4-N) increased by more than 100 times and concentrations of soluble reactive phosphorus (SRP) increased by more than an order of magnitude. In contrast, concentrations of nitrate...

Hybrid models offer the opportunity to improve future growth projections by combining advantages of both empirical and process-based modeling approaches. Hybrid models have been constructed in several regions and their performance relative to a purely empirical approach has varied. A hybrid model was constructed for intensively managed Douglas-fir plantations in the Pacific Northwest by embedding a hierarchy of components representing fundamental processes into a spatially implicit individual-tree model.

A gap analysis was conducted to evaluate the extent to which genetic resources are conserved in situ in protected areas for six species of conifers in the Pacific Northwest. The gap analysis involved producing a geographic information system (GIS) detailing the location of protected areas and the distribution and abundance of tree species, as inferred from data on potential plant association groups, actual plant associations, and actual land cover type. The GIS also employed two schemes for stratifying the distribution of each species into genetic populations for analysis: seed zones and...

We examined the effect of forest thinning and riparian buffers along headwater streams on terrestrial salamanders at two sites in western Oregon. Salamander numbers were reduced postthinning at one site with lower down-wood volume. Terrestrial salamander distributions along stream-to-upslope transects suggest benefits of one and two site-potential tree-height stream buffers for upslope species.

The use of Granier-style heat dissipation sensors to measure sap flow is common in plant physiology, ecology, and hydrology. There has been concern that any change to the original Granier design invalidates the empirical relationship between sap flux density and the temperature difference between the probes. We compared daily water use estimates from gravimetric measurements with values from variable-length heat dissipation sensors, which are a relatively new design. In general, the comparison showed the minor changes to the original Granier-type sensors does not affect the empirical...

A scientific foundation coupled with technical support is needed to develop long-term strategic plans for fuel and vegetation treatments on public lands. These plans are developed at several spatial scales and are typically a component of fire management plans and other types of resource management plans. Such plans need to be compatible with national, regional, and local strategies for fuel treatments, as well as other aspects of resource management. Scientific documentation provides principles and tools that inform management decisions about fuels treatments, contribute to the application...

Incidence and effects of tree damage by black bear (Ursus americanus altifrontalis) in a 50-year-old, coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) plantation are described. Bears girdled or partially girdled 35 dominant or codominant Douglas-fir trees per acre, but only in that portion of the plantation that had been interplanted at age 4 with red alder (Alnus rubra Bong). No red alder were damaged. Bears damaged Douglas-fir in this stand on at least four occasions between 1929 (planting) and 1991. Fully girdled Douglas-fir (six per acre in 1976) died within 2 to...

This guidebook describes the Saddle Bag Mountain Research Natural Area, a 121-ha (300-ac) tract established to represent an old-growth remnant of Pacific silver fir (Abies amabilis) and western hemlock (Tsuga heterophylla) forest in the Oregon Coast Range. Pacific silver fir and noble fir (Abies procera) occur as isolated remnants, and both species are approaching the southern limits of their natural range in the Oregon Coast Range.