Nitrogen immobilization in decaying hardwood leaf litter as a function of initial nitrogen and lignin content

1982 ◽  
Vol 60 (11) ◽  
pp. 2263-2269 ◽  
Author(s):  
John D. Aber ◽  
Jerry M. Melillo
Keyword(s):  
Leaf Litter ◽  
Pacific Northwest ◽  
Nitrogen Availability ◽  
Lignin Content ◽  
Nitrogen Immobilization ◽  
Important Species ◽  
Hardwood Species ◽  
The Pacific ◽  
Successional Species ◽  
Using Data

Equations presented in an earlier paper, expressing organic matter and nitrogen dynamics in decomposing hardwood leaf litter, are extended to predict nitrogen immobilization patterns in litters of varying initial lignin and nitrogen content. A continuum of immobilization rates coincides with the successional status of the six northern hardwood species examined, with early successional species exhibiting the fastest rates. By using data from the literature, similar trends were found for southeastern hardwoods. Patterns for important species from Douglas-fir forests of the Pacific Northwest are quite different and may reflect differences in nitrogen availability following disturbance.

Low Mortality of Larval Lampreys from Electrofishing, Suction-pumping, Anesthesia, and Handling

2017 ◽  
Vol 8 (2) ◽  
pp. 640-647 ◽  
Author(s):  
Jeffrey C. Jolley ◽  
Christina T. Uh ◽  
Gregory S. Silver ◽  
Timothy A. Whitesel
Keyword(s):  
Pacific Northwest ◽  
Control Group ◽  
Long Term Effects ◽  
Negative Effects ◽  
Short Term ◽  
Important Species ◽  
Pacific Lamprey ◽  
The Pacific ◽  
Delayed Mortality

Abstract Native lamprey populations are declining worldwide. In the Pacific Northwest focus on conservation and management of these ecologically and culturally important species has increased. Concern has emerged regarding the effects of sampling and handling of lamprey, with little to no attention given to the larval lifestage. We monitored the survival of larval Pacific Lamprey Entosphenus tridentatus and Lampetra spp. after backpack electrofishing, deepwater electrofishing and suction-pumping, anesthesia, and handling. We performed survival trials on wild-caught lamprey (n = 15 larvae in each trial) collected from the Clackamas River drainage in Oregon, USA, coupled with control group trials from lamprey sourced from a hatchery (n = 10 larvae). Short-term (96 h) survival was >98% with only one observed mortality. Delayed mortality (1 wk) was observed for four individuals that had fungus; two of those were positive for the bacteria Aeromonas hyrdrophila. We recorded blood hematocrit as a secondary measure of stress. The baseline, nonstressed larvae hematocrit levels did not differ from those of fish that had undergone stress through electrofishing, suction-pumping, and handling without anesthesia. Electrofishing, suction-pumping, and anesthesia showed no short-term negative effects on larval lamprey although potential long-term effects remain unstudied. These techniques appear to provide efficient and relatively safe methods for collecting and surveying larval lamprey.

scholarly journals Comparison of Coastal Fringe and Interior Forests as Reserves for Marbled Murrelets on Vancouver Island

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 915-920
Author(s):  
Alan E. Burger ◽  
Volker Bahn ◽  
Angeline R. M. Tillmanns
Keyword(s):  
Pacific Northwest ◽  
Structural Diversity ◽  
Vancouver Island ◽  
Old Growth ◽  
Brachyramphus Marmoratus ◽  
Marbled Murrelet ◽  
The Pacific ◽  
Using Data ◽  
Associated Species ◽  
Marbled Murrelets

Abstract Much of the protected habitat available to the threatened Marbled Murrelet Brachyramphus marmoratus and other old-growth associated species in the Pacific Northwest is in narrow strips along the coast (e.g., parks and scenic fringes). Using data over two years from three watersheds on southwest Vancouver Island, we show that such shoreline strip forests represent suboptimal habitat for murrelets. Murrelet detections, including circling and subcanopy behaviors, were significantly lower at 30 coastal stations (20–250 m from the shoreline edge) than at 30 interior stations (1.5–21.0 km inland). Densities of predators were significantly higher at the coastal stations. The coastal trees were of similar mean height and diameter, but they had lower structural diversity and provided fewer and less suitable (thinner epiphyte cover on large boughs) nesting platforms than trees in the interior. When possible, reserves for Marbled Murrelets should be placed in interior and not shoreline forests.

Impact of Moisture Flux and Freezing Level on Simulated Orographic Precipitation Errors over the Pacific Northwest

2013 ◽  
Vol 14 (1) ◽  
pp. 140-152 ◽  
Author(s):  
Yanluan Lin ◽  
Brian A. Colle ◽  
Sandra E. Yuter
Keyword(s):  
Pacific Northwest ◽  
Mesoscale Model ◽  
Moisture Flux ◽  
Orographic Precipitation ◽  
Surface Precipitation ◽  
Freezing Level ◽  
The Pacific ◽  
Using Data ◽  
Oregon Cascades ◽  
Ice Water

Abstract Two cool seasons (November–March) of daily simulations using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) over the Pacific Northwest are used to investigate orographic precipitation bias. Model simulations are compared with data from a radiosonde site at Salem, Oregon, just upstream (west) of the Oregon Cascades; precipitation gauges over a portion of the Pacific Northwest; and a National Weather Service Weather Surveillance Radar-1988 Doppler (WSR-88D) in Portland, Oregon. The 77 storms analyzed are partitioned into warm/cold storms based on the freezing level above/below the Oregon Cascades crest (~1600 m MSL). Although the seasonal precipitation is well simulated, the model has a tendency to overpredict surface precipitation for cold storms. The correlation between the upstream relative humidity–weighted integrated moisture transport and precipitation for warm storms (r2 = 0.81) is higher than that for cold storms (r2 = 0.54). Comparisons of model ice water content (IWC) and derived reflectivity with radar-retrieved IWC and observed reflectivity for the 38 well-simulated storms show reasonably good agreement for warm storms but an overprediction of IWC and reflectivity aloft for cold storms. One plausible reason for the persistent overprediction of IWC in cold storms might be related to the positive bias in snow depositional growth formulation in the model bulk microphysics parameterization. A favorable overlap of the maximum snow depositional growth region with the mountain wave ascent region in cold storms magnifies the bias and likely contributes to the precipitation overprediction. This study also highlights the benefit of using data aloft from an operational radar to complement surface precipitation gauges for model precipitation evaluation over mountainous terrain.

Understanding soil nutrients and characteristics in the Pacific Northwest through parent material origin and soil nutrient regimes

2011 ◽  
Vol 41 (10) ◽  
pp. 2001-2008 ◽  
Author(s):  
K.M. Littke ◽  
R.B. Harrison ◽  
D.G. Briggs ◽  
A.R. Grider
Keyword(s):  
Pacific Northwest ◽  
Soil Nitrogen ◽  
Forest Floor ◽  
Nitrogen Availability ◽  
Soil Depth ◽  
Soil Nutrient ◽  
Soil Characteristics ◽  
Douglas Fir ◽  
Parent Materials ◽  
The Pacific

A convenient method is necessary for assessing the availability of soil nitrogen in plantation Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands in the Pacific Northwest. The objective of this research was to use soil parent materials (SPMs) and soil nutrient regimes (SNRs) to determine the most efficient method to characterize soil nitrogen availability in Douglas-fir stands. It was hypothesized that SPMs and SNRs would effectively separate stands with distinctive climate, site, and soil characteristics and forest floor and soil carbon and nitrogen reserves. At 60 Douglas-fir stands, SPMs and SNRs were determined, and soil particle percentages, soil depth, and forest floor and soil nitrogen and carbon contents were measured to a depth of 1 m. Soils of sedimentary origin and very rich and rich SNRs contained greater nitrogen and carbon contents than those from glacial and igneous origins and medium SNRs. Sedimentary SPMs and very rich SNRs were developed from older parent materials and had significantly greater soil depths and finer textures than those from glacial SPMs and medium SNRs. SNRs and SPMs are recommended as good estimators of soil nutrient pools and soil characteristics in Douglas-fir plantation forests of the Pacific Northwest.

Riparian forest harvesting and its influence on benthic communities of small streams of sub-boreal British Columbia

2007 ◽  
Vol 37 (5) ◽  
pp. 907-918 ◽  
Author(s):  
K. Jill Melody ◽  
John S. Richardson
Keyword(s):  
Leaf Litter ◽  
Pacific Northwest ◽  
Riparian Forest ◽  
Benthic Communities ◽  
Forest Harvesting ◽  
Riparian Areas ◽  
The Pacific ◽  
Small Streams ◽  
Coastal Streams ◽  
Physical Features

Forest harvesting in riparian areas can alter the leaf-litter inputs, shading, and stability of small streams, and many of the details of these impacts are known for coastal streams of the Pacific Northwest. However, little is known about how small streams in the drier, continental areas of western North America respond to logging. We conducted a study of paired stream reaches (comparing one recently harvested (≤3 years) reach and two upstream, forested reaches in each of five streams) in which periphyton, detritus, macroinvertebrate abundance and biomass, and physical features were measured in summer and autumn. In general, recently harvested stream sections tended to be wider and contained more riffle areas than the upstream forested sections. The amounts of leaf litter and algae varied among streams and were not consistently greater or lesser in the forested sections than in the harvested sections. Though the variation in amounts within streams was mainly seasonal, amounts differed more among streams than between pairs of harvested and forested reaches. The communities of benthic invertebrates differed significantly between forested and harvested reaches, but often in opposite directions between streams. The magnitude and direction of differences observed between treatments, streams, or seasons were associated with the specific stream and the method of riparian harvesting used.

scholarly journals Using data analytics to further understand the role that boredom, loneliness, social anxiety, social gratification, and social relationships (BRAG) play in a driver’s decision to text

2016 ◽  
Vol 4 (2) ◽  
pp. 1-16
Author(s):  
Nathan White ◽  
Yair Levy ◽  
Steven R. Terrell ◽  
Steve Bronsburg
Keyword(s):  
Social Anxiety ◽  
Pacific Northwest ◽  
Social Relationships ◽  
The United States ◽  
Texting While Driving ◽  
Regional University ◽  
The Pacific ◽  
Using Data ◽  
Visualization Techniques ◽  
Social Gratification

Texting while driving is a growing problem that current efforts have failed to curtail. This behavior has serious, and sometimes fatal, consequences, and the factors that cause a driver to text are not well understood. This study investigates the influence that boredom, social relationships, social anxiety, and social gratification (BRAG) have upon the texting driver. A survey instrument was used to collect data from 297 respondents at a mid-sized regional university in the Pacific Northwest of the United States. The data was evaluated with PLS-SEM, which indicated that social gratification plays a very significant role in a driver’s decision to text. Additionally, data visualization techniques were used to gain additional knowledge from the data. The analysis with these techniques indicated that social anxiety may also play a role in a driver’s decision to text.

Estimating large-root biomass from stump and breast-height diameters for Douglas-fir in western Oregon

1996 ◽  
Vol 26 (2) ◽  
pp. 237-243 ◽  
Author(s):  
Walter G. Thies ◽  
Patrick G. Cunningham
Keyword(s):  
Pacific Northwest ◽  
Root Biomass ◽  
Dry Weight ◽  
Belowground Biomass ◽  
Douglas Fir ◽  
Large Root ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
The Pacific ◽  
Using Data

Estimates of belowground biomass are fundamental to understanding carbon cycling and sequestration and the dynamics of ecological systems and in designing studies of those systems. An important belowground component of stands in the Pacific Northwest is the large-root biomass associated with mature, second-growth, Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco). Sample Douglas-fir from four western Oregon stands were felled, and their stumps and root systems were excavated and cleaned. Biomass of all roots larger than 10 mm in diameter plus the belowground portion of the stump was determined on a dry-weight basis. Each tree was measured for stump diameter, 15 cm above the soil line, and for diameter at breast height. Regression models were constructed by using data from 82 trees from four stands. Stump diameters ranged from 24.1 to 92.5 cm, diameter at breast height ranged from 21.3 to 54.6 cm, and biomass ranged from 20.5 to 614.4 kg.

Suitability of Natural Areas for Representing Ecological Change in the Pacific Northwest

2019 ◽  
Vol 39 (4) ◽  
pp. 452
Author(s):  
Margaret H. Massie ◽  
Todd M. Wilson ◽  
Anita T. Morzillo ◽  
Emilie B. Henderson
Keyword(s):  
Pacific Northwest ◽  
Ecological Change ◽  
Natural Areas ◽  
The Pacific
Sign in / Sign up

Export Citation Format

Share Document