Sources of large wood in the main stem of a fourth-order watershed in coastal Oregon

2003 ◽  
Vol 33 (8) ◽  
pp. 1363-1370 ◽  
Author(s):  
Gordon H Reeves ◽  
Kelly M Burnett ◽  
Edward V McGarry
Keyword(s):  
Pacific Northwest ◽  
Fourth Order ◽  
Flow Channel ◽  
Main Stem ◽  
Low Flow ◽  
Large Wood ◽  
Coast Range ◽  
Riparian Management ◽  
The Pacific ◽  
Management Approaches

We compared the contribution of large wood from different sources and wood distributions among channel zones of influence in a relatively pristine fourth-order watershed in the central Coast Range of Oregon. Wood in the main stem of Cummins Creek was identified as coming from either (i) streamside sources immediately adjacent to the channel or (ii) upslope sources delivered by landslides or debris flows more than 90 m from the channel. About 65% of the number of pieces and 46% of the estimated volume of wood were from upslope sources. Streamside sources contributed about 35% of the number of pieces and 54% of the estimated volume of wood. The estimated mean volume of upslope-derived pieces was about one-third that of streamside-derived pieces. Upslope-derived pieces were located primarily in the middle stream reaches and in the zones of influence that had the most contact with the low-flow channel. Streamside-derived pieces were more evenly distributed among the examined reaches and were predominately in the influence zones that had the least contact with the low-flow channel. Our findings suggest that previous studies that examined only streamside sources of wood have limited applications when designing and evaluating riparian management approaches in landslide-prone areas. The failure to recognize the potential sources of wood from upslope areas is a possible reason for the decline of large wood in streams in the Pacific Northwest.

scholarly journals Economic Costs of Different Riparian Management Regulations in the Pacific Northwest

2007 ◽  
Vol 22 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Kevin W. Zobrist ◽  
Bruce R. Lippke
Keyword(s):  
Pacific Northwest ◽  
Lower Cost ◽  
Riparian Habitat ◽  
Economic Costs ◽  
Wood Production ◽  
Riparian Management ◽  
The Pacific ◽  
Western Washington ◽  
Management Issues

Abstract Riparian management is an important consideration for sustainable wood production in the Pacific Northwest. Western Washington and Oregon have similar riparian management issues but different regulatory prescriptions. Application of these prescriptions to a sample of 10 small private ownerships illustrate some of the economic differences of each state's approach. Economic costs tend to be higher in Washington but can be significant in both states. Lower cost strategies through alternate plans may be important for protecting riparian habitat while ensuring the long-term economic viability of forestry in the region.

Riparian tree fall directionality and modeling large wood recruitment to streams

2006 ◽  
Vol 36 (5) ◽  
pp. 1243-1254 ◽  
Author(s):  
Daniel J Sobota ◽  
Stanley V Gregory ◽  
John Van Sickle
Keyword(s):  
Pacific Northwest ◽  
Field Data ◽  
Riparian Forest ◽  
Large Wood ◽  
Riparian Trees ◽  
The Pacific ◽  
Riparian Tree ◽  
Individual Trees ◽  
Fall Direction ◽  
Recruitment Model

Directionality of tree fall in riparian forests can strongly influence predictions of large wood recruitment to streams, yet accuracy of this model parameter has rarely been assessed with field data. We measured fall directions of 1202 riparian trees distributed among 21 stream sites across the Pacific Northwest, USA. Fall directions were oriented towards the stream at 16 sites, upstream at four sites, and not distinguishable from random at one site. Average tree fall direction across sites was correlated with valley constraint (Spearman r = –0.53; p = 0.02), but variability of fall directions was not correlated with this variable. When grouped by species (six conifers and one deciduous), individual trees exhibited stronger tendency to have fallen towards the channel on steep hillslopes (>40%) than on moderately sloped landforms (<40%). Integration of field data into an established recruitment model indicated that 1.5 to 2.4 times more large wood (by number of tree boles) would be recruited to stream reaches with steep hillslopes than to reaches with moderate side slopes or flat banks, if riparian forest conditions are assumed to be constant. We conclude that stream valley topography should be considered in models that use tree fall directions in predictions of large wood recruitment to streams.

Predicting deposition of debris flows in mountain channels

1990 ◽  
Vol 27 (4) ◽  
pp. 409-417 ◽  
Author(s):  
Lee E. Benda ◽  
Terrance W. Cundy
Keyword(s):  
Pacific Northwest ◽  
Debris Flows ◽  
Field Measurements ◽  
Coast Range ◽  
Oregon Coast Range ◽  
Oregon Coast ◽  
Aerial Photos ◽  
The Pacific ◽  
Channel Slope ◽  
Junction Angle

An empirical model for predicting deposition of coarse-textured debris flows in confined mountain channels is developed based on field measurements of 14 debris flows in the Pacific Northwest, U.S.A. The model uses two criteria for deposition: channel slope (less than 3.5°) and tributary junction angle (greater than 70°). The model is tested by predicting travel distances of 15 debris flows in the Oregon Coast Range and six debris flows in the Washington Cascades, U.S.A. The model is further tested on 44 debris flows in two lithological types in the Oregon Coast Range using aerial photos and topographic maps; on these flows only the approximate travel distance is known. The model can be used by resource professionals to identify the potential for impacts from debris flows. Key words: debris flow, deposition, travel, erosion.

IMPLICATIONS OF RIPARIAN MANAGEMENT STRATEGIES ON WOOD IN STREAMS OF THE PACIFIC NORTHWEST

2003 ◽  
Vol 13 (5) ◽  
pp. 1212-1221 ◽  
Author(s):  
Mark A. Meleason ◽  
Stanley V. Gregory ◽  
John P. Bolte
Keyword(s):  
Pacific Northwest ◽  
Management Strategies ◽  
Riparian Management ◽  
The Pacific

Late-Glacial Vegetation and Climate Change in Western Oregon

1998 ◽  
Vol 49 (3) ◽  
pp. 287-298 ◽  
Author(s):  
Laurie D. Grigg ◽  
Cathy Whitlock
Keyword(s):  
Pacific Northwest ◽  
Younger Dryas ◽  
Late Glacial ◽  
Warming Trend ◽  
Cascade Range ◽  
Subalpine Forest ◽  
Coast Range ◽  
The Pacific ◽  
Dry Conditions ◽  
Vegetation And Climate

Pollen records from two sites in western Oregon provide information on late-glacial variations in vegetation and climate and on the extent and character of Younger Dryas cooling in the Pacific Northwest. A subalpine forest was present at Little Lake, central Coast Range, between 15,700 and 14,850 cal yr B.P. A warm period between 14,850 and 14,500 cal yr B.P. is suggested by an increase in Pseudotsuga pollen and charcoal. The recurrence of subalpine forest at 14,500 cal yr B.P. implies a return to cool conditions. Another warming trend is evidenced by the reestablishment of Pseudotsuga forest at 14,250 cal yr B.P. Increased haploxylon Pinus pollen between 12,400 and 11,000 cal yr B.P. indicates cooler winters than before. After 11,000 cal yr B.P. warm dry conditions are implied by the expansion of Pseudotsuga. A subalpine parkland occupied Gordon Lake, western Cascade Range, until 14,500 cal yr B.P., when it was replaced during a warming trend by a montane forest. A rise in Pinuspollen from 12,800 to 11,000 cal yr B.P. suggests increased summer aridity. Pseudotsuga dominated the vegetation after 11,000 cal yr B.P. Other records from the Pacific Northwest show an expansion of Pinus from ca. 13,000 to 11,000 cal yr B.P. This expansion may be a response either to submillennial climate changes of Younger Dryas age or to millennial-scale climatic variations.

scholarly journals Characterizing aquatic habitats for long-term monitoring of a fourth-order, regulated river in the Pacific Northwest, USA

2017 ◽  
Vol 34 (1) ◽  
pp. 24-33 ◽  
Author(s):  
C.P. Konrad ◽  
K. Burton ◽  
R. Little ◽  
A.D. Gendaszek ◽  
M.D. Munn ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Fourth Order ◽  
Regulated River ◽  
Aquatic Habitats ◽  
The Pacific ◽  
Long Term Monitoring ◽  
Term Monitoring

scholarly journals Effects of Forest Harvesting on Warm-Season Low Flows in the Pacific Northwest: A Review

2020 ◽  
Vol 4 (1) ◽  
pp. 29
Author(s):  
R.D. (Dan) Moore ◽  
Stefan Gronsdahl ◽  
Richard McCleary
Keyword(s):  
Pacific Northwest ◽  
Forest Disturbance ◽  
Fish Habitat ◽  
Warm Season ◽  
Forest Harvesting ◽  
Low Flow ◽  
Post Harvest ◽  
Low Flows ◽  
The Pacific ◽  
Paired Catchment

Paired-catchment studies conducted on small (< 10 km2) rain-dominated catchments revealed that forest harvesting resulted in a period of increased warm-season low flows ranging from less than five years to more than two decades, consistent with the results of stand-level studies and process considerations. Of the five paired-catchment studies in snow-dominated regions, none revealed a statistically significant change in warm-season low flows in the first decade following harvest, although two exhibited non-significant higher flows in August and September and one had lower flows. Two studies, one of rain-dominated catchments and one of snow-dominated catchments, found that summer low flows became more severe (i.e., lower) about two decades or so following harvest. These longer-term results indicate that indices such as equivalent clearcut area, as currently calculated using monotonic recovery curves, may not accurately reflect the nature of post-harvest changes in low flows. Studies focussed on medium to large catchments (tens to thousands of km2 in area) found either no statistically significant relations between warm-season low flows and forest disturbance, or inconsistent responses. Attempts to synthesize existing studies are hampered by the lack of a common low-flow metric among studies, as well as detailed information on post-harvest vegetation changes. Further fieldresearch and process-based modelling is required to help elucidate the underlying processes leading to the results from these paired-catchment studies and to enhance the ability to predict streamflow responses to forest harvesting, especially in the context of a changing climate. KEYWORDS: streamflow; forestry; low flows; fish habitat; hydrologic recovery

scholarly journals Molecules to Mountains: A Multi-Proxy Investigation Into Ancient Climate and Topography of the Pacific Northwest, USA

2021 ◽  
Vol 9 ◽  
Author(s):  
Alexander McLean ◽  
John Bershaw
Keyword(s):  
Pacific Northwest ◽  
Global Climate ◽  
Milankovitch Cycles ◽  
Coast Range ◽  
The Pacific ◽  
Term Variation ◽  
History Of ◽  
Oregon Cascades ◽  
Topographic Evolution

We characterize the topographic evolution of the Pacific Northwest, United States, during the Cenozoic. New paleosol carbonate stable isotope (δ18O) results from central Oregon are presented, along with published proxy data, including fossil teeth, smectites, and carbonate concretions. We interpret a polygenetic history of Cascade Mountain topographic uplift along-strike, characterized by: 1) Steady uplift of the Washington Cascades through the Cenozoic due long-term arc rotation and shortening against a Canadian buttress, and 2) Uplift of the Oregon Cascades to similar-to-modern elevations by the late Oligocene, followed by topographic stagnation as extension developed into the Neogene. Since the Miocene, meteoric water δ18O values have decreased in Oregon, possibly due to emergence of the Coast Range and westward migration of the coastline. Spatial variability in isotopic change throughout the Pacific Northwest suggests that secular global climate change is not the primary forcing mechanism behind isotopic trends, though Milankovitch cycles may be partly responsible for relatively short-term variation.

Interaction of vegetation control and fertilization on conifer species across the Pacific Northwest

2002 ◽  
Vol 32 (1) ◽  
pp. 136-152 ◽  
Author(s):  
Robin Rose ◽  
J Scott Ketchum
Keyword(s):  
Weed Control ◽  
Pacific Northwest ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tsuga Heterophylla ◽  
Stem Volume ◽  
Coast Range ◽  
Basal Diameter ◽  
Vegetation Control ◽  
The Pacific

An experiment evaluating three levels of vegetation competition control (no control, 1.5 m2 of vegetation control, and 3.3 m2 of vegetation control), each with two fertilization treatments (fertilization at the time of planting with complete slow-release fertilizer (Woodace® IBDU), or no fertilization), was installed at five sites. Two of these sites were planted with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in the Oregon Coast Range, one with ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws.) in eastern Washington, one with western hemlock (Tsuga heterophylla (Raf.) Sarg.) in the coastal hemlock zone in Oregon, and one with coastal redwood (Sequoia sempervirens (D. Don) Endl.) in northern California. At four of the five sites, mean stem volume, basal diameter, and height of seedlings increased significantly with increasing area of weed control, and the magnitude of difference between treatments increased with time. Fertilization significantly increased seedling size only at the two sites with adequate soil moisture; increases were marginally significant at a third. Response to fertilization was less than from weed control and impacted growth for only the first year, whereas the influence of weed control continued to influence growth the entire length of the study (4 years). Area of vegetation control and fertilization did not interact significantly at any site.

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