Northwest Science

© 2006 by the Northwest Scientific Association The acorn woodpecker is among the most common primary cavity nesting bird of the Oregon white oak woodlands. In most of their range, acorn woodpeckers are dependent on granaries for acorn storage, yet little is known about their selection of granary sites. We compared habitat characteristics within 12 m of granary and non-granary trees at 20 acorn woodpecker colonies in Benton County, Oregon during the winter of 2001. Compared to non-granaries, granary plots consistently had greater oak basal area and shorter shrub height, and granary trees were of larger diameter. Within each of the 20 sites, oak basal area was greater near granary than non-granary trees. This, together with the selection for larger diameter granaries, suggests acorn woodpeckers are more likely to locate granaries in the immediate area of high acorn production. Increased acorn production in the vicinity of granaries is likely beneficial to the birds because minimal effort is expended in caching maximum forage. Our results shed light on granary selection at the spatial scale of the immediate area surrounding granaries and suggest factors associated with acorn woodpecker distribution at the landscape scale.
A widespread and intense spruce beetle outbreak during the 1990s has killed most of the mature white spruce (Picea glauca) trees across many watersheds in south-central Alaska. To investigate the potential habitat impacts in a salmon stream, we characterized the current abundance and species composition of large woody debris (LWD), examined the linkages between LWD and salmonid habitat, and estimated changes in LWD abundance and associated pool habitat over time. LWD abundance was relatively low (97 pieces/km overall) and varied widely according to riparian vegetation typology, ranging from 15 pieces/km at sites with non-forested riparian zones to 170 pieces/km at sites adjacent to cottonwood forest. LWD provided significant fish cover in pools, especially in cottonwood forest stream reaches. LWD-formed pools were relatively rare (15% of total), but LWD abundance explained much of the variation in pool frequency (r2 = 0.86 in spruce forest reaches) and in the proportion of pool habitats (r2 = 0.85 in cottonwood forest reaches). We project the spruce beetle outbreak to result in a substantial net increase in LWD abundance over a 50-year span, peaking with 243% and 179% increases in LWD abundance for spruce forest and cottonwood forest stream reaches, respectively, in the year 2025. Concurrent with the peak in LWD abundance, our estimates show pool frequency in spruce forest reaches to reach 207% of current levels and the proportion of pools in cottonwood forest reaches to reach 167% of current levels, changes that correspond with substantially increased potential habitat for juvenile salmonids.
Where timber production is the primary management objective, knowledge of the relationship between the potential productivity of candidate tree species and levels of light, heat, nutrient, moisture and aeration is necessary for species- and site-specific decision making. For example, foresters need to decide which tree species to regenerate on a particular harvested area to obtain maximum sustainable productivity. Similarily, when considering the application of silvicultural treatments such as spacing or fertilizing, foresters need to determine whether the potential productivity of a particular site warrants the cost of the treatment. We used the site index (height of dominant trees at breast height age) of western redcedar (Thuja plicata Donn. ex D. Don.) as a measure of productivity, and described the pattern of mean site index in relation to field identified soil moisure and soil nutrient regimes. Forest Sciences, Dept of Peer-Reviewed
Douglas-fir dwarf mistletoe brooms provide important wildlife habitat but also have detrimental effects on host tree vigor. Forest managers can use information about broom development to balance competing objectives of providing wildlife habitat and maintaining healthy trees. We collected data on thirty Douglas-fir trees and their associated dwarf mistletoe brooms before and after felling on four sites. Cross-sections cut from each infected branch and broom were used to determine the ages of the branches, the ages when they became infected and the age of each mistletoe broom. There were no strong relationships between broom size and broom age, or broom size and distance from the bole, height or platform size, the number of brooms in the trees, their Broom Volume Rating, diameter, age, crown class or surrounding density. This suggested that heavily infected or old infected trees may not necessarily yield the greatest number of large brooms for wildlife habitat. There were significant differences in the size, age and position of different types of brooms. Comparing the brooms in our sample with data from studies of spotted owl nests revealed differences among broom types that may be useful for management of infected stands in forests where maintaining broom habitat for wildlife is a consideration.
Thesis (M.S.)--University of Washington, 1989. Includes bibliographical references (leaves [59]-63).
ill., maps; Typescript (photocopy); Thesis (M.S.)-Oregon State University, 1975; Includes bibliographical references (leaves 120-127)
Ordination of 27 forest floor samples and means for each stand type as functions of the first two canonical variables, based on forest floor nutrient properties significantly discriminating among stand types (pH, C:N, Ca, and Mg) (p <0.10). Abbreviations for stand types are: Hwwestern hemlock, Cw-western redcedar, HwCw-western hemlock-western redcedar.
The influence of tree species on forest soils has been the subject of study for at least a century. Of particular interest have been western hemlock (Tsuga heterophylla (Raf.) Sarg.) and western redcedar (Thuja plicata Donn ex D. Don) – two of the most common tree species in coastal and southern British Columbia, but each with a different nutrient amplitude. It has generally been found that acid, mycogeneous Mor humus forms develop in hemlock stands, while less acid and more zoogenous Mormoder, Moder, or even Mull humus forms develop in redcedar stands. The objective of this study was to determine the influence of hemlock and redcedar, growing separately and together, on forest floor nutrient properties. The questions addressed were: (1) does each stand type have unique forest floor nutrient properties? and (2) can any forest floor nutrient property discriminate between stand types? Forest Sciences, Dept of Peer-Reviewed
The invasive virile crayfish Faxonius virilis (Hagen 1870) has recently been documented in the upper Snake River drainage of Idaho, but its distribution is poorly known. Our objective was to determine the presence and distribution of F. virilis in the Henrys Fork drainage of the Snake River. Sampling was conducted during summer and autumn 2018 at 30 sites located in Henrys Fork River drainage, including the major tributaries Teton River, North Fork Teton River, South Fork Teton River, and Moody Creek. We used baited minnow traps and kick nets to determine presence of F. virilis. Absence was only reported if we unsuccessfully captured F. virilis using kick nets because this technique is more effective. Faxonius virilis was detected in all five streams. We did not detect F. virilis at sites at the upstream extent of sampling. This pattern suggests that F. virilis are invading the drainage in an upstream direction. Presence of species of conservation concern (e.g., Yellowstone cutthroat trout [Oncorhynchus clarkii bouvieri Jordan and Gilbert 1883], bluehead sucker [Catostomus discobolus Cope 1871], and western pearlshell [Margaritifera falcata Gould 1850]) warrant additional research to determine the effect of F. virilis on these species.
The Taku Glacier, is a temperate, maritime glacier of the Juneau Icefield, southeast Alaska. This glacier is the largest of the icefield, and has advanced 6.8 km since 1890, 1.6 km since 1948. The mass balance record of the Taku Glacier (1946-1986) indicates that the glacier's continued advance has been due to positive mass balance. Due to the large surplus balance of the previous 40 years the Taku Glacier will continue to advance for the remainder of this century. -from Authors
Nonnative plant species continue to be introduced into North America both accidentally and intentionally for horticultural and agricultural purposes. Some new species will spread extensively and some will become weeds of importance. We used a floristic database (INVADERS) to examine the status of incipient plant invasions in the northwest United States (Washington, Oregon, Idaho, Montana and Wyoming). We queried INVADERS for distribution records of plant species exotic to North America that were first recorded in the northwest states during 1950-1996. The query resulted in records for 288 species, of which 133 were judged to have become established (based on collector notes), or to have high potential to spread beyond artificial environments such as lawns and gardens. Inherent potential for invasion was based on examination of several invasive plant lists and the international literature on plant invasions. Thirty species have become moderately widespread (reported from >5 counties) in the five-state northwest region, and several are known to be aggressive invaders in other regions of North America or in other parts of the world. Five species discussed in the text are notable for rapid spread and/or indications of aggressiveness: Polygonum cuspidatum (syn: Fallopia japonica, Reynoutria japonica), Bryonia alba, Impatiens glandulifera, Hieracium pratense and Scorzonera laciniata. Compared with the early exotics (mid 1800s - early 1900s), which tended to be annual herbs, the post-1950 exotic flora shows a trend toward greater proportions of perennials and woody growth forms (shrubs and trees). Some applications of floristic databanks in regional-scale management of plant invasions are discussed.
Map of Chickaloon Flats, Kenai National Wildlife Refuge, Alaska. Estuarine intertidal zones derived from National Wetlands Inventory data (US Fish and Wildlife Service) and data from The National Map (USGS). Map displayed in the Alaska Albers Equal Area Conic Projection (NAD83 datum).
The 2005 maximum likelihood supervised classification of Chickaloon Flats, Kenai National Wildlife Refuge, Alaska with four land cover classes.
Change in land cover classification from 1970 to 2005 at Chickaloon Flats, Kenai National Wildlife Refuge, Alaska. Demonstrates the geographic distribution of changes (or lack of change) in community type.
Chickaloon Flats, Kenai National Wildlife Refuge, is a 10,000 ha tidal mudflat complex on the Kenai Peninsula in southcentral Alaska. It is a protected coastal estuary stopover area along the Pacific Flyway, covering 7% of the total estuarine intertidal area from Cook Inlet to Prince William Sound. Because Chickaloon Flats is historically an important avian migratory stopover and has relative regional importance in terms of estuarine intertidal area, there was a need to evaluate the current vegetation and determine any changes since the last ground study in 1972. We collected land cover data at a sample of ground-truthed points on Chickaloon Flats during 2009–2010 to evaluate existing vegetation communities as compared to historic 1970–71 values. A maximum likelihood supervised classification was performed on 2005 Landsat TM imagery to create an updated land cover classification of Chickaloon Flats. We used two different analytical approaches to show that the most notable changes in land cover types from 1975–2005 were the increase in early successional communities and a decline in unvegetated mud. Additionally, inland land cover types, which represent the more stable marsh-like communities, decreased in area as a whole. The documented changes in vegetation composition and structure over the four decade study period are attributable to elevation changes from sediment accretion and post-1964 Earthquake subsidence. As a result, evidence points to reduced shorebird use of the Flats.
The sixth edition (1983) of the American Ornithologist's Union Check-list of North American Birds contains numerous systematic changes from the fifth edition (1957). -from Author
On the evening of 9 May 1986, a hot, newly extruded portion of the lava dome in the crater of Mount St. Helens collapsed onto the late spring snowpack, generating a flow which traveled the length of the crater with an average velocity of 5 m/s. At Loowit gaging station, 2.4 km from the dome, the flow had an instantaneous peak discharge of 230 m³/s and was a high discharge water event, not a debris flow. However, within the next 1-2 km the flow incorporated sufficient solids to evolve into a debris flow with a velocity of 5.5-6.5 m/s and a peak discharge of 870 m³/s. The debris flow attenuated rapidly upon reaching the flat expanse of Step Fan and left recognizable deposits for only 3 km beyond the base of the mountain. -from Authors
Subareas of the Salish Sea used for analyses of spatial use. The international boundary is shown. The northernmost area of the Gulf Islands and Strait of Georgia and the westernmost area of the Strait of Juan de Fuca had less small boat and sighting effort, thus were excluded from our analyses. 
Cumulative annual occurrence of mammal-eating killer whales in the Salish Sea by subarea from 1987–1993 and 2004–2010. 
Cumulative monthly oc currence of mammal-eating killer whales in the Salish Sea by subarea from 1987–1993 and 2004–2010. 
Percent of occurrences for each observed minimum group size of mammal-eating killer whales in the Salish Sea from 1987–1993 and 2004–2010. From 1987–1993, modal group size was 3 whales (mean ± SD: 4.40 ± 2.82). From 2004–2010, modal group size was 4 whales (5.17 ± 4.36). 
Cumulative monthly occurrence of non-nearshore and nearshore foragers from 1987–1993 and 2004–2010. 
The primary prey species of mammal-eating killer whales in the Salish Sea, the inland waters of southern British Columbia and Washington state, have experienced dramatic increases in population abundances in the last 25 years. It is possible that changes in prey abundance over time have resulted in changes in predator spatial use, occurrence and group size. Focused studies of mammal-eating killer whale behavior in the area were undertaken from 1987-1993, and an extensive record of sightings with confirmed identifications was available from 2004-2010. Changes in occurrence across years, months, and subareas of the Salish Sea were examined as well as changes in group size and in the identity of specific matrilines using the area. Occurrence of mammal-eating whales increased significantly from 2004-2010 with different seasonal peaks compared to 1987-1993. Different matrilines occurred in different seasons, time periods, and subareas. Group size was larger in 2004-2010 than in 1987-1993. The whales may be increasing use of the area due to increasing prey abundance or an overall increase in the whale population size. Changes in seasonal patterns of occurrence and the increase in group size between the two periods could be due to increased prey diversity.
From 1993 to 2007, we used single pass, September surveys to locate and measure fluvial bull trout (Salvelinus confluentus) redds in Rapid River, Idaho. Here we describe substrate sizes, redd dimensions, and water depths, velocities, and temperatures within and adjacent to 337 redds. Most (79%) spawning sites had fewer than 20% surface fines (< 2 mm) and mean, annual water depths and velocities ranged from 14.2-23.0 cm and 11.6-30.5 cm s⁻¹, respectively. Mean, annual completed redd total lengths and surface areas averaged from 1.03-1.47 m and 0.37-1.07 m⁻², respectively. Pea gravel (2 to < 8 mm) and gravel (8-64 mm) were dominant substrates (> 60%) in redds. Bull trout altered channel water depths and velocities during redd construction; pits averaged 5 cm deeper, leading tailspill edges 1.2 cm shallower, and tailspill crests 6.2 cm shallower than adjacent, undisturbed sites. Conversely, pit velocities averaged 2.1 cm s⁻¹ slower, tailspill edge velocities 2.3 cm s⁻¹ faster, and tailspill crest velocities 10.1 cm s⁻¹ faster than adjacent sites. Mean, annual pit water temperatures ranged from 4.5 to 7.7 °C. Water depths and water velocities over undisturbed sites adjacent to bull trout redds were significantly correlated with water depths and water velocities inside completed redds. Improving our understanding of fluvial bull trout redds will increase the accuracy of redd counts, especially in streams with sympatric, fall spawning salmonids. Data describing fine-scale characteristics of redds and adjacent sites will assist efforts to conserve and restore critical bull trout spawning habitats.
The Elwha River dams have disconnected the upper and lower Elwha watershed for over 94 years. This has disrupted salmon migration and reduced salmon habitat by 90%. Several historical salmonid populations have been extirpated, and remaining populations are dramatically smaller than estimated historical population size. Dam removal will reconnect upstream habitats which will increase salmonid carrying capacity, and allow the downstream movement of sediment and wood leading to long-term aquatic habitat improvements. We hypothesize that salmonids will respond to the dam removal by establishing persistent, self-sustaining populations above the dams within one to two generations. We collected data on the impacts of the Elwha River dams on salmonid populations and developed predictions of species-specific response dam removal. Coho (Oncorhynchus kisutch), Chinook (O. tshawytscha), and steelhead (O. mykiss) will exhibit the greatest spatial extent due to their initial population size, timing, ability to maneuver past natural barriers, and propensity to utilize the reopened alluvial valleys. Populations of pink (O. gorbuscha), chum (O. keta), and sockeye (O. nerka) salmon will follow in extent and timing because of smaller extant populations below the dams. The initially high sediment loads will increase stray rates from the Elwha and cause deleterious effects in the egg to outmigrant fry stage for all species. Dam removal impacts will likely cause a lag in recolonization and population rebuilding. These negative sediment effects will be locally buffered by the extent of functioning floodplain, and management attempts to minimize sediment impacts. Resident life forms of char (Salvelinus confluentus), rainbow trout (O. mykiss), and cutthroat (O. clarki) will positively interact with their anadromous counterparts resulting in a positive population level response.
Timber cruise data can provide useful information not available elsewhere. Measurements of timber volume (timber cruises) from the early 20th century for Coos County, Oregon, were used to assess the degree to which tree species distribution and timber volume varied with edaphic and climatic factors. The study area has diverse geology in a moderate maritime climate, and represents an area of forest transition between the Coast Range and the Klamath Mountains. Species distribution was determined from 629 cruised 1-mi2 (2.59 km²) sections, and timber volume from 252 sections of old-growth forest. Most forests were dominated by Douglas-fir (Pseudotsuga menziesii); Sitka spruce (Picea sitchensis), although least frequent, had the second-most timber volume. All six commercial conifer species differed substantially in distribution in relation to geography and to environment. Both distribution and volume of grand fir (Abies grandis) varied with geologic unit and general soil type: Sitka spruce, with soil and maximal summer temperature (-sign); Douglas-fir, with temperature (+) and summer precipitation (+); western hemlock (Tsuga heterophylla), with precipitation (+); Port-Orford-cedar (Chamaecyparis lawsoniana), with precipitation (-); and western redcedar (Thuja plicata), with no factor. Importance of Douglas-fir and hemlock increased on geologic units with sediments from inland plutonic sources, which reduced importance of Port-Orford-cedar. Some species varied significantly among soil units within a geological formation, and vice-versa. When choosing which species to plant, these cruise data can supplement or replace guidelines based on plant associations. © 2018 by the Northwest Scientific Association. All rights reserved.
Top-cited authors
James K. Agee
  • University of Washington Seattle
Andrew B. Carey
  • Serendipity Consulting, Ashford, WA
James M Trappe
  • Oregon State University
Brenda McComb
  • Oregon State University
Charles B. Halpern
  • University of Washington Seattle