Large woody debris in bull trout (Salvelinus confluentus) spawning streams of logged and wilderness watersheds in northwest Montana

1999 ◽  
Vol 56 (6) ◽  
pp. 915-924 ◽  
Author(s):  
F Richard Hauer ◽  
Geoffrey C Poole ◽  
John T Gangemi ◽  
Colden V Baxter
Keyword(s):  
Woody Debris ◽  
Rocky Mountain ◽  
Large Woody Debris ◽  
Mountain Streams ◽  
Bull Trout ◽  
Stream Channel ◽  
Salvelinus Confluentus ◽  
Stream Bank ◽  
Northwestern Montana ◽  
Bankfull Width

We measured large woody debris (LWD) in 20 known bull trout (Salvelinus confluentus) spawning stream reaches from logged and wilderness watersheds in northwestern Montana. Mean bankfull width of stream reaches was 14.1 m ranging from 3.9 to 36.7 m. Streams were large enough to move LWD and form aggregates. We determined the characteristics of individual pieces of LWD that were interactive with the stream channel. Large, short pieces of LWD attached to the stream bank were the most likely to be positioned perpendicular to stream flow, while large, long pieces either tended to be parallel to the flow or, when attached, were most apt to extend across the channel thalweg. Observations indicated that the majority of pools were formed as scour pools by either very large LWD pieces that were perpendicular to the stream or multipiece LWD aggregates. Among reaches in wilderness watersheds, ratios of large to small LWD, attached to unattached LWD, and with and without rootwads were relatively consistent. However, among reaches with logging in the watershed, these ratios varied substantially. These results suggest that logging can alter the complex balance of delivery, storage, and transport of LWD in northern Rocky Mountain streams, and therefore, the likely substantive change in stream habitats.

Characteristics and function of large woody debris in subalpine Rocky Mountain streams in northern Colorado

1995 ◽  
Vol 52 (8) ◽  
pp. 1789-1802 ◽  
Author(s):  
Ann D. Richmond ◽  
Kurt D. Fauseh
Keyword(s):  
Pacific Northwest ◽  
Woody Debris ◽  
Fish Habitat ◽  
Rocky Mountain ◽  
Large Woody Debris ◽  
Mountain Streams ◽  
Coastal Forests ◽  
The Pacific ◽  
And Function ◽  
Rocky Mountain Streams

Large woody debris has been well studied in coastal forests of the Pacific Northwest, but little is known of its role in Rocky Mountain streams. Large woody debris was measured in 11 undisturbed streams draining subalpine old-growth forests in north central Colorado to assess abundance, characteristics, and function. Although large woody debris in Colorado had smaller diameter, length, and volume than in the Pacific Northwest, its abundance and function were similar. The majority of pools (76%) were plunge and dammed pools formed by large woody debris, most of which spanned the channels perpendicular to stream flow. Smaller streams had a greater proportion of such perpendicular pool-forming pieces than larger streams. Four disturbed streams had significantly less and smaller large woody debris than undisturbed streams. Flows in larger undisturbed streams were capable of moving large woody debris, so pieces were more often located at the stream margins, oriented diagonally, or distributed in clumps than in smaller streams. Individual pools were larger and deeper in larger streams, but their size was not related to the size of large woody debris pieces forming them. Therefore, the function of large woody debris in forming fish habitat in small Rocky Mountain streams is strongly influenced by the stream's location within the watershed.

Movement and characteristics of stream-borne coarse woody debris in adjacent burned and undisturbed watersheds in Wyoming

1994 ◽  
Vol 24 (9) ◽  
pp. 1933-1938 ◽  
Author(s):  
Michael K. Young
Keyword(s):  
Coarse Woody Debris ◽  
Woody Debris ◽  
Rocky Mountain ◽  
Mountain Streams ◽  
Bank Stability ◽  
Stream Surface ◽  
Riparian Trees ◽  
Mean Diameter ◽  
Debris Transport ◽  
The Mean

Following fire, changes in streamflow and bank stability in burned watersheds can mobilize coarse woody debris. In 1990 and 1991, I measured characteristics of coarse woody debris and standing riparian trees and snags in Jones Creek, a watershed burned in 1988, and in Crow Creek, an unburned watershed. The mean diameter of riparian trees along Jones Creek was less than that of trees along Crow Creek, but the coarse woody debris in Jones Creek was greater in mean diameter. Tagged debris in Jones Creek was three times as likely to move, and moved over four times as far as such debris in Crow Creek. In Jones Creek, the probability of movement was higher for tagged pieces that were in contact with the stream surface. Larger pieces tended to be more stable in both streams. It appears that increased flows and decreased bank stability following fire increased the transport of coarse woody debris in the burned watershed. Overall, debris transport in Rocky Mountain streams may be of greater significance than previously recognized.

scholarly journals Evidence of Climate-Induced Range Contractions in Bull Trout Salvelinus confluentus in a Rocky Mountain Watershed, U.S.A

PLoS ONE ◽  
2014 ◽  
Vol 9 (6) ◽  
pp. e98812 ◽  
Author(s):  
Lisa A. Eby ◽  
Olga Helmy ◽  
Lisa M. Holsinger ◽  
Michael K. Young
Keyword(s):  
Rocky Mountain ◽  
Bull Trout ◽  
Salvelinus Confluentus ◽  
Mountain Watershed

Mechanisms and source distances for the input of large woody debris to forested streams in British Columbia, Canada

2011 ◽  
Vol 41 (11) ◽  
pp. 2231-2246 ◽  
Author(s):  
N.T. Johnston ◽  
S.A. Bird ◽  
D.L. Hogan ◽  
E.A. MacIsaac
Keyword(s):  
British Columbia ◽  
Woody Debris ◽  
Tree Height ◽  
Large Woody Debris ◽  
Source Distance ◽  
Standing Dead ◽  
A Site ◽  
Bankfull Width ◽  
Domain Concept ◽  
Channel Type

The geomorphic process domain concept predicts consistent associations between stream channel geomorphology and large woody debris (LWD) input mechanisms. We used synoptic surveys at 51 stream reaches adjacent to undisturbed mature or old-growth forests in central and southern British Columbia to test associations between stream geomorphology and the input processes, source distances, physical characteristics, and geomorphic functions of LWD within the bankfull channel. Standing dead tree fall was the dominant input mechanism, but bank erosion was important in low- and medium-gradient channels >3 m bankfull width. Wind-induced inputs (stem breakage and windthrow) were relatively more important in small or steep channels. LWD piece size and source distance varied among delivery processes. LWD originated at ground distances up to 65 m from the streams, but 90% of the LWD at a site originated within 18 m of the channel at 90% of the sites. Statistical models incorporating tree size and stream characteristics (bankfull width, channel type) explained 40%–64% of the variation among sites in the distances from which LWD entered streams. In general, LWD source distances increased with increasing tree height and decreased with increasing stream width; however, the strengths of these relationships were modified by channel type.

Dynamics of large woody debris in streams in old-growth Douglas-fir forests

1987 ◽  
Vol 17 (2) ◽  
pp. 150-156 ◽  
Author(s):  
G. W. Lienkaemper ◽  
F. J. Swanson
Keyword(s):  
Woody Debris ◽  
Douglas Fir ◽  
Large Woody Debris ◽  
Time And Space ◽  
Old Growth ◽  
Order Stream ◽  
Fifth Order ◽  
Bankfull Width ◽  
Downstream Movement

Transfer of large woody debris (>10 cm diameter) from old-growth Douglas-fir (Pseudotsugamenziesii (Mirbel) Franco) forests into five first-to fifth-order stream reaches (drainage areas of 0.1 to 60.5 km2) has ranged from 2.0 to 8.8 Mg•ha−1•year−1 in 7- to 9-year study periods. Amounts of large debris in these streams range from 230 to 750 Mg•ha−1 with generally lower values in larger channels. The addition of woody debris is widely scattered in time and space and comes mainly from single trees rooted away from the streambank. We infer that wind is a major agent for entry of wood into these streams. Downstream movement of debris is strongly related to length of individual pieces; most pieces that moved were shorter than bankfull width.

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