Controls on conifer regeneration in managed riparian forests: effects of seed source, substrate, and vegetation

2001 ◽  
Vol 31 (3) ◽  
pp. 471-482 ◽  
Author(s):  
Eric W Beach ◽  
Charles B Halpern
Keyword(s):  
Pacific Northwest ◽  
Woody Debris ◽  
Full Range ◽  
Plant Cover ◽  
Riparian Forests ◽  
Competitive Interactions ◽  
Vegetation Control ◽  
Seed Availability ◽  
Seed Sources ◽  
Conifer Regeneration

Red alder (Alnus rubra Bong.) commonly dominates the overstory in managed riparian forests of the Pacific Northwest. Although it is assumed that competition with a dense shrub layer inhibits succession from hardwoods to shade-tolerant conifers within these forests, this assumption has not been explicitly tested. We hypothesized that seed availability rather than competitive interactions largely shape patterns of conifer regeneration in managed riparian forests. At nine locations in western Washington, we established paired transects in riparian sites adjacent to abundant versus few or no sources of seed to examine the importance for conifer regeneration of dispersal limitation, rooting substrate, and vegetation cover. Frequency and density of regeneration were significantly greater in transects within 100 m of remnant forest patches than in paired sites at greater distances (mean frequencies of 59 vs. 18% and densities of 0.23 vs. 0.16 trees/m2, respectively). Where seed sources were present, regeneration was positively associated with coarse woody debris and negatively associated with fine litter. Regeneration was most abundant in plots with <10% herb or shrub cover; however, for most species, recruitment occurred across the full range of understory plant cover. We detected no relationship between regeneration density and overstory conifer or hardwood cover. Our results suggest that, in managed forests, conifer regeneration is largely limited by seed availability and only secondarily by competitive interactions or substrate conditions. In managed landscapes, conventional strategies of vegetation control are not likely to be as effective in increasing conifer regeneration in riparian forests as managing for seed sources through green-tree retention.

Synergistic stem volume response to combinations of vegetation control and seedling size in conifer plantations in Oregon

2006 ◽  
Vol 36 (4) ◽  
pp. 930-944 ◽  
Author(s):  
Lee S Rosner ◽  
Robin Rose
Keyword(s):  
Weed Control ◽  
Pacific Northwest ◽  
Analysis Of Covariance ◽  
Stem Volume ◽  
Conifer Species ◽  
Basal Diameter ◽  
Vegetation Control ◽  
Seedling Size ◽  
Volume Response ◽  
Stock Types

There are few published studies examining the effects of the interaction of seedling size and vegetation control on the growth of Pacific Northwest conifer species. Data from two vegetation management studies encompassing five planting sites, four conifer species, and two stock types were analyzed to determine the relative effects of seedling size at planting and intensity of vegetation control on subsequent seedling growth. Study 1 tested eight combinations of annual broadcast weed control or no weed control applied over the course of 5 years. Study 2 tested spot herbicide applications of differing area, as well as herbaceous-only and woody-only control treatments. The effect of seedling size was determined by analysis of covariance, with basal diameter as the covariate. Both seedling size and weed control increased growth of all conifer species through 4, 5, or 12 years, but responses varied by species and site. Diameter and height responses to weed control and seedling size were additive, whereas volume differences between treatments increased with increasing seedling size. The implication for management is that the volume return from increased weed control is maximized by planting the largest possible seedlings; conversely, the volume from increased seedling size is maximized at the highest weed control intensities.

Keepability of Pennsylvania versus West Coast Grown Douglas-Fir Christmas Trees: Genotypic Variation in Relation to Subfreezing Temperatures

1990 ◽  
Vol 7 (2) ◽  
pp. 86-89 ◽  
Author(s):  
Mark E. Kubiske ◽  
Marc D. Abrams ◽  
James C. Finley
Keyword(s):  
Pacific Northwest ◽  
Genotypic Variation ◽  
Rocky Mountain ◽  
Douglas Fir ◽  
Seed Sources ◽  
Christmas Trees ◽  
Display Area ◽  
The Pacific ◽  
Significant Difference ◽  
Needle Loss

Abstract Cut Douglas-fir Christmas trees grown in Pennsylvania from Rocky Mountain seed sources and coastal trees grown in the Pacific Northwest and shipped into Pennsylvania were compared for keepability. Following various cold treatments, the cut ends of trees were placed in water in an indoor display area. Coastal trees placed in a freezer at - 29°C for 24 h had 89 ± 5.1% (mean ± standard error) needle loss after one day of display, while Rocky Mountain origin trees exhibited only 3 ± 2.0% needle loss after 1 day and 50 ± 5.6% needle loss after 18 days. Coastal produced trees exposed to temperatures > - 12°C had 50 ± 9.8% needle loss at the end of the experiment, while Rocky Mountain trees ended with 22 ± 3.2% needle loss. Four additional treatments consisted of trees placed on an outdoor lot and periodically moved indoors to simulate Christmas tree market activity. Again, there was a significant difference between trees from coastal and Rocky Mountain sources, with 57.2 ± 4.3% and 11.8 ± 1.2% needle loss after 3 days, respectively. By the end of the 23 day experiment, the coastal trees were essentially devoid of needles, whereas Rocky Mountain trees had an average of only 20% needle loss. Coastal trees also exhibited a very noticeable loss of color and lustre. North. J. Appl. For. 7:86-89, June 1990.

How direct and indirect non-native interactions can promote plant invasions, lead to invasional meltdown and inform management decisions.

2020 ◽  
pp. 153-176
Author(s):  
Sara E. Kuebbing
Keyword(s):  
Native Species ◽  
Native Plants ◽  
Full Range ◽  
Invasion Biology ◽  
Apparent Competition ◽  
Indirect Interactions ◽  
Competitive Interactions ◽  
Invasional Meltdown ◽  
Soil Microbial ◽  
Facilitative Interactions

Abstract In 1999, Daniel Simberloff and Betsy Von Holle introduced the term 'invasional meltdown'. The term and the concept have been embraced and critiqued but have taken a firm hold within the invasion biology canon. The original formulation of the concept argued two key points: first, biologists rarely study how non-natives interact with one another. Second, nearly all the conceptual models about the success and impact of invasive species are predicated on the importance of competitive interactions and an implicit assumption that non-natives should interfere with establishment, spread and impact of other non-natives. In response, Simberloff and Von Holle called for more research on invader interactions and proposed an alternative consequence of non-native species interactions - invasional meltdown - where facilitative interactions among non-natives could increase the invasion rate or ecological impacts in invaded systems. This chapter outlines the primary pathways in which direct and indirect interactions among non-natives could lead to invasional meltdown. It provides examples of how different types of interactions among non-natives could lead to net positive effects on the invasion success of non-native plants or the impact of non-native plants on invaded ecosystems. Direct effects are by far the most commonly explored form of non-native- non- native interaction, primarily focusing on plant mutualisms with pollinators, seed dispersers or soil microbial mutualists. There are, however, also examples of non-native plants that benefit from commensal and even herbivorous interactions with other non-natives. Indirect interactions among non-natives are very infrequently studied. Although examples are scarce, non-natives may indirectly benefit other non-native plants through trophic cascades, apparent competition and indirect mutualisms. It remains unclear whether indirect effects are important pathways to invasional meltdown. More work is needed on studying ecosystems that are invaded by multiple non-native species and we need to consider the full range of interactions among non-natives that could either stymie or promote their spread, population growth and impact. Only then can we address how common facilitative interactions are relative to competitive interactions among non-natives or provide robust suggestions on how to manage ecosystems.

scholarly journals Soil phosphorus fractions vary with harvest intensity and vegetation control at two contrasting Douglas-fir sites in the Pacific northwest

Geoderma ◽  
2019 ◽  
Vol 350 ◽  
pp. 73-83 ◽  
Author(s):  
Daniel G. DeBruler ◽  
Stephen H. Schoenholtz ◽  
Robert A. Slesak ◽  
Brian D. Strahm ◽  
Timothy B. Harrington
Keyword(s):  
Pacific Northwest ◽  
Soil Phosphorus ◽  
Douglas Fir ◽  
Phosphorus Fractions ◽  
Vegetation Control ◽  
Soil Phosphorus Fractions ◽  
Harvest Intensity ◽  
The Pacific

scholarly journals From vacant land to urban fallows: a permacultural approach to wasted land in cities and suburbs

2019 ◽  
Vol 26 (1) ◽  
pp. 282 ◽  
Author(s):  
Alex Korsunsky
Keyword(s):  
Pacific Northwest ◽  
Full Range ◽  
Intentional Communities ◽  
Vacant Land ◽  
Residential Areas ◽  
The Pacific ◽  
Alternative Approach ◽  
New Urbanist ◽  
American Cities ◽  
The City

<p>While vacant land in cities has long been considered a sign of decline, a growing literature now suggests that such land can serve valuable social and ecological functions. In this article, I argue that such approaches advocated to date, while beneficial, operate within a New Urbanist framework that is essentially concerned with filling in vacant land with new 'green' projects. Unfortunately, such approaches are limited by a conceptualization of the city that treats inner city vacant lots as paradigmatic and makes invisible the systematic creation of functionally vacant land through zoning and building practices in low-density residential areas. Inspired by degrowth scholarship, I suggest that permaculture may provide the basis for an alternative approach based in the concept of fallowing more suited to the full range of vacant land present in American cities and suburbs. I explore the implications of such an approach through the practice of two permaculture-inspired intentional communities in the Pacific Northwest.</p><strong>Key words: </strong>vacant land, permaculture, New Urbanism, intentional communities, commons, degrowth

Linking instream wood recruitment to adjacent forest development in landscapes driven by stand-replacing disturbances: a conceptual model to inform riparian and stream management

2020 ◽  
Vol 28 (4) ◽  
pp. 517-527
Author(s):  
Kyle D. Martens ◽  
Daniel C. Donato ◽  
Joshua S. Halofsky ◽  
Warren D. Devine ◽  
Teodora V. Minkova
Keyword(s):  
Conceptual Model ◽  
Pacific Northwest ◽  
Timber Harvest ◽  
Riparian Forests ◽  
Conservation Strategy ◽  
Forest Development ◽  
Stage Of Development ◽  
Instream Wood ◽  
Shaped Pattern ◽  
Over Time

Instream wood plays an important role in stream morphology and creation of fish habitat in conifer forests throughout the temperate zone. In some regions, such as the US Pacific Northwest, many streams currently have reduced amounts of instream wood due to past management activities (timber harvest, wood removal, etc.). These reductions exist against a backdrop of naturally dynamic amounts and distributions of instream wood, which likely fluctuate over time based in part on the stage of development (disturbance and succession) in adjacent riparian forests. Despite many studies on both forest development and instream wood accumulation, the linkages between these processes have not been fully described, particularly as they relate to stream restoration needs. In this paper, we combine literature on forest development, disturbance, and processes that drive instream wood recruitment to more explicitly connect the temporal dynamics of stream wood inputs with the dynamics of adjacent riparian forests. We use moist forests of the Pacific Northwest as an exemplary system, from which to draw broadly applicable patterns for landscapes influenced by stand-replacing disturbance regimes. This conceptual model highlights a U-shaped pattern of instream wood recruitment, in which instream wood is highest after a stand-replacing disturbance and during the old-growth stage, and lowest through the middle stages of forest development (currently the most abundant stages in many landscapes as a result of past forest management practices). This mid-successional period of scarce wood is likely exacerbated in streams with a history of wood removal. The U-shaped pattern suggests that, without higher-than-average levels of disturbance, many streams in landscapes dominated by mid-successional second-growth forests (∼30–80 yr old) will be deficient of instream wood until forest stands are over 200 years old. As such, the balance between the predominant riparian conservation strategy of passive restoration (e.g., unharvested riparian reserves) and the alternative of active restoration (e.g., wood additions and (or) riparian stand treatments) should be carefully considered, depending on management objectives, site context, and potential tradeoffs over time.

Managing for Mature Habitat in Production Forests of Western Oregon and Washington

1996 ◽  
Vol 10 (2) ◽  
pp. 422-428 ◽  
Author(s):  
Elizabeth C. Cole
Keyword(s):  
Pacific Northwest ◽  
Coarse Woody Debris ◽  
Management Practices ◽  
Woody Debris ◽  
Wildlife Habitat ◽  
Low Grade ◽  
Habitat Features ◽  
Canopy Opening ◽  
Tolerant Species ◽  
Shade Tolerant Species

Standard timber management practices in the Pacific Northwest result in stands which often vary from unmanaged stands in structure and composition. Forest and wildlife managers have identified a deficit of stands in the mature (> 100-yr-old) age class that contain certain desirable wildlife habitat features. Techniques are being developed that would increase the likelihood that managed stands can produce these characteristics. The key desirable components in these stands include large (> 75 cm diam breast height) conifer trees, snags, coarse woody debris, and understory structure, including regeneration. Vegetation management techniques can facilitate development of these components within stands. Thinning the overstory, underplanting shade-tolerant species, and creating snags and coarse woody debris can be accomplished within a production forest. Maintaining shade-intolerant species requires a higher level of disturbance and canopy opening than needed for shade-tolerant species. Treatments which remove competition from shrubs and herbaceous plants may be necessary to insure growth and survival of understory regeneration. Injection of different herbicides into low-grade conifers may yield different types of snags in comparison to girdling or topping. Although much of the understory may be eliminated during future thinnings and final harvest, some of the structure will remain and could be carried over into the next rotation along with snags and large coarse woody debris. These treatments are expected to enhance mature habitats in present and future cycles with minimum impact on yield.

Chinese Privet (Ligustrum sinense) Removal and its Effect on Native Plant Communities of Riparian Forests

2009 ◽  
Vol 2 (4) ◽  
pp. 292-300 ◽  
Author(s):  
James L. Hanula ◽  
Scott Horn ◽  
John W. Taylor
Keyword(s):  
Plant Communities ◽  
Foliar Application ◽  
Plant Cover ◽  
Riparian Forests ◽  
Active Management ◽  
Native Plant ◽  
Chinese Privet ◽  
Desirable Outcome ◽  
Understory Plant ◽  
Future Condition

AbstractChinese privet is a major invasive shrub within riparian zones throughout the southeastern United States. We removed privet shrubs from four riparian forests in October 2005 with a Gyrotrac® mulching machine or by hand-felling with chainsaws and machetes to determine how well these treatments controlled privet and how they affected plant community recovery. One year after shrub removal a foliar application of 2% glyphosate was applied to privet remaining in the herbaceous layer. Three “desired-future-condition” plots were also measured to assess how well treatments shifted plant communities toward a desirable outcome. Both methods completely removed privet from the shrub layer without reducing nonprivet shrub cover and diversity below levels on the untreated control plots. Nonprivet plant cover on the mulched plots was > 60% by 2007, similar to the desired-future-condition plots and higher than the hand-felling plots. Both treatments resulted in higher nonprivet plant cover than the untreated controls. Ordination showed that after 2 yr privet removal plots were tightly grouped, suggesting that the two removal techniques resulted in the same plant communities, which were distinctly different from both the untreated controls and the desired-future-condition. Both treatments created open streamside forests usable for recreation and other human activities. However, much longer periods of time or active management of the understory plant communities, or both, will be required to change the forests to typical mature forest plant communities.

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.

scholarly journals Modeling early forest succession following clear-cutting in western Oregon

2005 ◽  
Vol 35 (8) ◽  
pp. 1889-1900 ◽  
Author(s):  
Zhiqiang Yang ◽  
Warren B Cohen ◽  
Mark E Harmon
Keyword(s):  
Pacific Northwest ◽  
Forest Succession ◽  
Canopy Cover ◽  
Growth Function ◽  
Life Forms ◽  
Aerial Photographs ◽  
Coast Range ◽  
Clear Cutting ◽  
Conifer Regeneration ◽  
Richards Function

In the Pacific Northwest, the process of conifer development after stand-replacing disturbance has important implications for many forest processes (e.g., carbon storage, nutrient cycling, and biodiversity). This paper examines conifer development in the Coast Range Province and Western Cascades Province of Oregon using repeat interpretation of historic aerial photographs from 1959 to 1997 to examine the canopy cover change of different life forms: shrubs, hardwood trees, and conifer trees. Ninety-four stands from the Western Cascades Province and 59 stands from the Coast Range Province were photointerpreted in roughly 5-year intervals. A Chapman–Richards growth function was used to model conifer cover development for all sample stands. Based on the photo data and the Chapman–Richards function, these stands were classified into one of seven early forest successional trajectories defined by the vegetation physiognomy. Succession in the Coast Range Province and Western Cascades Province were compared using parameters derived from the Chapman–Richards growth function. Our results echo previous studies in that rates and densities of conifer regeneration varied markedly among sites; however, our results also indicate that early forest succession differs in the two study regions in terms of both trajectories and rates. Conifer regeneration in the Western Cascades Province tends to have longer delays in establishing and slower rates compared with the Coast Range Province.

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