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.

Fire Whirlwinds

1955 ◽  
Vol 36 (3) ◽  
pp. 99-103 ◽  
Author(s):  
Howard E. Graham
Keyword(s):  
Pacific Northwest ◽  
Field Data ◽  
General Behavior ◽  
The Pacific ◽  
Favorable Conditions

Description and general behavior of fire whirlwinds in the Pacific Northwest are outlined, field data are presented and conclusions are drawn as to favorable conditions. The behavior of observed fire whirlwinds agrees well with related aerodynamic theory.

Long-term monitoring of the recruitment and dynamics of large wood in Kamienica Stream, Polish Carpathians

2020 ◽  
Author(s):  
Paweł Mikuś ◽  
Bartłomiej Wyżga
Keyword(s):  
Fourth Order ◽  
Flood Hazard ◽  
Riparian Forest ◽  
Woody Debris ◽  
Large Wood ◽  
Order Stream ◽  
Riparian Trees ◽  
Metal Plates ◽  
Polish Carpathians

&lt;p&gt;Quantifying delivery and mobility of large woody debris in small mountain streams requires long-term and repeatable observations, so far very scarcely described. Such observations have been conducted in the upper course of Kamienica Stream, Polish Western Carpathians, where a sample of 429 trees growing along three separated sections of &amp;#160;the stream was tagged with metal plates and monitored during 10 years. The monitoring of standing and fallen trees has been conducted a few times per year, especially after heavy rainfall and windstorms. In this period, 96 trees (22.4% of the tagged sample) were recruited to the channel during high-intensity meteorological and hydrological events, mostly as a result of bank erosion during floods and windthrow, with recent bark beetle infestation of the riparian forest considerably accelerating the turnover of riparian trees. Large wood inventory performed in 2012 in the second- to fourth-order stream reaches and of the 10 years-long monitoring of tagged trees indicated variable mobility of large wood along the upper course of the stream. Wood mobility was negligible in the second-order reach, very small in the third-order reach, and higher, but still limited in the fourth-order reach. 46 trees were subjected to transport during five significant floods, and mean lengths of displacement of the tagged trees were small, not exceeding 32 m in sections A and B, whereas in section C they were a few times longer. However, an advanced state of decay of most pieces leads to their disintegration during floods, rather than to distant transport, and thus large wood retained in the upper stream course within a national park does not constitute an important flood hazard to downstream, inhabited valley reaches.&lt;/p&gt;

scholarly journals Widespread dieback of riparian trees on a dammed ephemeral river and evidence of local mitigation by tributary flows

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2622 ◽  
Author(s):  
Caitlin M. S. Douglas ◽  
Mark Mulligan ◽  
Xavier A. Harrison ◽  
Joh R. Henschel ◽  
Nathalie Pettorelli ◽  
...  
Keyword(s):  
Channel Flow ◽  
River Flow ◽  
Main Channel ◽  
Riparian Trees ◽  
Ephemeral Rivers ◽  
Riparian Tree ◽  
Tree Dieback ◽  
Anthropogenic Threats ◽  
Individual Trees ◽  
Key Resources

Ephemeral rivers act as linear oases in drylands providing key resources to people and wildlife. However, not much is known about these rivers’ sensitivities to human activities. We investigated the landscape-level determinants of riparian tree dieback along the Swakop River, a dammed ephemeral river in Namibia, focusing on the native ana tree (Faidherbia albida) and the invasive mesquite (Prosopisspp.). We surveyed over 1,900 individual trees distributed across 24 sites along a 250 km stretch of the river. General linear mixed models were used to test five hypotheses relating to three anthropogenic threats: river flow disruption from damming, human settlement and invasive species. We found widespread dieback in both tree populations: 51% mortality in ana tree, with surviving trees exhibiting 18% canopy death (median); and 26% mortality in mesquite, with surviving trees exhibiting 10% canopy death. Dieback in the ana tree was most severe where trees grew on drier stretches of the river, where tributary flow was absent and where mesquite grew more abundantly. Dieback in the mesquite, a more drought-tolerant taxon, did not show any such patterns. Our findings suggest that dieback in the ana tree is primarily driven by changes in river flow resulting from upstream dam creation and that tributary flows provide a local buffer against this loss of main channel flow. The hypothesis that the invasive mesquite may contribute to ana tree dieback was also supported. Our findings suggest that large dams along the main channels of ephemeral rivers have the ability to cause widespread mortality in downstream riparian trees. To mitigate such impacts, management might focus on the maintenance of natural tributary flows to buffer local tree populations from the disruption to main channel flow.

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.

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.

Predicting postfire mortality of seven western conifers

1988 ◽  
Vol 18 (10) ◽  
pp. 1291-1297 ◽  
Author(s):  
Kevin C. Ryan ◽  
Elizabeth D. Reinhardt
Keyword(s):  
Pacific Northwest ◽  
Regression Models ◽  
Tree Mortality ◽  
Binary Logistic Regression ◽  
Mortality Data ◽  
Prescribed Fires ◽  
Logistic Regression Models ◽  
Mortality Probability ◽  
The Pacific ◽  
Individual Trees

We used data on 2356 trees from 43 prescribed fires in Idaho, Montana, Oregon, and Washington states to model postfire tree mortality. Data were combined for seven species of conifers to develop binary logistic regression models for predicting the probability of mortality. Probability of mortality increased with percentage of the crown killed, and decreased as bark thickness increased. Models are presented with and without species as a categorical variable. The models predicted well for trees burned in both slash fires and fires in natural fuels. The models are applicable for assessing fire-caused mortality both of individual trees and in mixed conifer stands of the Pacific Northwest.

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
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