Succession of bryophyte assemblages following clear-cut logging in boreal spruce-dominated forests in south-central Sweden — Does retrogressive succession occur?

2009 ◽  
Vol 39 (10) ◽  
pp. 1871-1880 ◽  
Author(s):  
Martin Schmalholz ◽  
Kristoffer Hylander
Keyword(s):  
Forest Succession ◽  
Canopy Cover ◽  
Recovery Process ◽  
Clear Cut ◽  
Positive Effects ◽  
Clear Cutting ◽  
Extinction Rates ◽  
South Central ◽  
Litter Cover

The recovery process of boreal bryophyte communities after clear-cutting was studied in a chronosequence in south-central Sweden. We hypothesized that high initial grass cover on clearcuts, high litter cover and low light levels during canopy closure, and shortage of coarse woody substrates would constrain recovery in different ways. Instead, both epigeic and epixylic guilds (i.e., species growing on forest floor and deadwood) displayed a gradual increase in similarity over time from the clear-cut phase, perhaps because of the absence of distinct peaks in needle litter and canopy cover. Epixylic species started to recover long before the accumulation of deadwood, indicating that microclimate rather than substrate availability was the most constraining factor during the first 50 years. Since we did not find any other bottlenecks during the succession after clear-cutting, conservation measures aiming at decreasing local extinction rates during clear-cutting may also increase long-term persistence. On the other hand, as the results from the epixylic guild suggest, other factors during the forest succession, such as the development of a suitable microclimate, might be more important for some organisms, thus possibly mitigating such long-term positive effects of adjusted management during the clear-cutting operation.

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.

Phosphorus forms and related soil chemistry of Podzolic soils on northern Vancouver Island. II. The effects of clear-cutting and burning

2000 ◽  
Vol 30 (11) ◽  
pp. 1726-1741 ◽  
Author(s):  
Barbara J Cade-Menun ◽  
Shannon M Berch ◽  
Caroline M Preston ◽  
L M Lavkulich
Keyword(s):  
Organic Matter ◽  
Vancouver Island ◽  
Available P ◽  
Resonance Spectroscopy ◽  
Inorganic P ◽  
Clear Cut ◽  
Podzolic Soils ◽  
Clear Cutting ◽  
Slash Burning

When cedar-hemlock (CH) forests of northern Vancouver Island are clear-cut and replanted, growth of replanted trees is often poor. This growth check can be overcome with nitrogen (N) and phosphorus (P) fertilization, suggesting that it may be because of deficiencies of these elements. A widely used site-preparation tool in these forests is slash burning. Because fire is known to alter nutrient cycling in forests, this burning may be contributing to the problem of poor seedling growth. Thus, the objective of this study was to compare P in forest floor and soils from clear-cut CH stands 10 years, 5 years, and immediately after burning to P concentrations and forms in undisturbed old growth CH stands. Analytical methods included extraction and digestion procedures, fractionation and 31P nuclear magnetic resonance spectroscopy. Soon after burning, an "ashbed effect" was noted, with increased pH and higher concentrations of available P in surface soil horizons. Available P concentrations and pH returned to preburn levels within 10 years. However, destruction of organic matter appeared to disrupt illuviation processes throughout the soil profile, producing long-term changes in organic matter, organic P, and organically complexed Fe and Al in lower mineral horizons. Total P concentrations were unchanged, but there was a shift from organic to inorganic P forms and changes in P forms with time at depth in the profile. These changes in P distribution and movement in the soil may contribute to the growth check observed in these forests.

Blue Grouse—Effects on, and Influences of, a Changing Forest

1985 ◽  
Vol 61 (2) ◽  
pp. 185-188 ◽  
Author(s):  
Fred C. Zwickel ◽  
James F. Bendell
Keyword(s):  
Forest Canopy ◽  
Management Practices ◽  
Forest Succession ◽  
Continuous Production ◽  
Rotation Period ◽  
Tree Canopy ◽  
Negative Effects ◽  
Clear Cut ◽  
Clear Cutting ◽  
Dendragapus Obscurus

Blue grouse (Dendragapus obscurus) may increase spectacularly in lowland Pacific coast forest that has been logged by clear-cutting. Locally, they may be used heavily by hunters, and more subtly, by nonconsumptive recreationsists. They can be sufficiently abundant to affect the survival of young conifers, the distribution of seeds and, perhaps, nutrient cycling. Blue grouse can represent a major component of the faunal biomass on a given area.Local populations of blue grouse change mainly as a result of forest management practices on lowland breeding ranges. Logging at higher elevations probably will not produce grouse in equivalent densities, and the implications of increased logging on winter range (at even higher elevations) are unknown.Current logging and silvicultural practices have both positive and negative effects on blue grouse. Newly logged lowlands are colonized rapidly by "surplus" grouse from nearby, established populations. They may persist in variable, but unpredictable, densities until forest canopy approaches 75% coverage. Populations decline due to non replacement of adults that die. Although clear-cutting often results in short-term, and occasionally large, increases in numbers, these persist for only about 25% or less of a planned rotation period. The productive period for occupancy by grouse may be shortened by early planting, planting everywhere, fertilization with urea, and by large, even-aged plantations. The productive period may be extended by delayed planting, a wider spacing within plantations, not planting sites of low timber productivity and, perhaps, by intensive thinning throughout the forest rotation, or cutting in small patches.An important key to continuous maintenance of breeding populations of blue grouse appears to be the presence of a well-developed and diverse understory. Alternatives to present clear-cutting practices that would leave a more open tree canopy would probably provide continuous production of grouse and many other species, albeit at a lower density than sometimes results from present programs. Experimental forests that can be manipulated in conjunction with long-term studies of the effects of these manipulations on wildlife are needed if we are to integrate forest - wildlife management practices fully. Keywords: blue grouse, Dendragapus obscurus, populations, clear-cut logging, silviculture, forest succession.

Sphagnum invasion after clear-cutting and excavator mounding in a hypermaritime forest of British Columbia

2004 ◽  
Vol 34 (8) ◽  
pp. 1730-1746 ◽  
Author(s):  
Taro Asada ◽  
Barry G Warner ◽  
Allen Banner
Keyword(s):  
British Columbia ◽  
Tsuga Heterophylla ◽  
Thuja Plicata ◽  
North Coast ◽  
Clear Cut ◽  
Clear Cutting ◽  
Lower Productivity ◽  
Sphagnum Girgensohnii ◽  
Thuja Plicata Donn

Sphagnum invasion 8 years after an experimental clear-cut and mounding field trial was examined in a mesic western redcedar (Thuja plicata Donn ex D. Don) – western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest on the outer north coast of British Columbia. Sphagnum invasion was prominent in wet hollows in the mounded blocks. Pioneer species, Sphagnum pacificum Flatb. and Sphagnum angustifolium (C. Jens. ex Russ.) C. Jens., were common despite being minor components in the precut forest. Sphagnum girgensohnii Russ., a species of forests, showed expanding colonies and contained some Sphagnum capillifolium (Ehrh.) Hedw. Comparisons of vertical growth and decomposition rates of Sphagnum in the experimental field site and in a nearby natural peatland suggest that peat accumulation potential in the Sphagnum colonies in the mounded blocks is similar to that in the natural peatland. These observations suggest that open peatland-type plant communities become established and paludification processes are beginning. Mounding may be an effective strategy for silvicultural management to improve tree growth in the short term but may initiate paludification and negatively impact forest productivity in the long term in hypermaritime lower productivity forests.

Long-term functional group recovery of lotic macroinvertebrates from logging disturbance

2010 ◽  
Vol 67 (7) ◽  
pp. 1126-1134 ◽  
Author(s):  
Damon T. Ely ◽  
J. Bruce Wallace
Keyword(s):  
North Carolina ◽  
Secondary Production ◽  
Forest Succession ◽  
Dry Mass ◽  
Taxonomic Composition ◽  
Biotic Index ◽  
Clear Cut ◽  
Aquatic Resource ◽  
Reference Stream

Clear-cut logging rapidly affects stream macroinvertebrates through substantial alteration of terrestrial–aquatic resource linkages; however, lesser known are the long-term influences of forest succession on benthic macroinvertebrate assemblages, which play key roles in stream ecosystem function. We compared secondary production and standing crops of detritus in two mountain headwater streams within Coweeta Hydrologic Laboratory, North Carolina, USA, as part of a long-term, paired-watershed investigation of macroinvertebrate recovery from whole-catchment logging. Mean annual habitat-weighted abundance and biomass in the disturbed stream (catchment entirely logged 26 years prior) did not differ from that of the reference stream, and secondary production was only 0.8 g ash-free dry mass (AFDM)·m–2·year–1 greater in the disturbed stream (disturbed, 10.1; reference, 9.3). Taxonomic composition, shredder–scraper ratios, and North Carolina biotic index scores were more similar between streams than in previous years. However, mean annual standing crops of benthic organic matter (BOM) were much lower in the disturbed stream (167 g AFDM·m–2) than in the reference stream (339 g AFDM·m–2), and the disturbed stream supported greater macroinvertebrate biomass per unit BOM. We suggest that despite similarities in macroinvertebrate structure and function, past logging activity continues to influence consumer–resource relationships in the disturbed stream through enhanced resource quality.

scholarly journals Effects of clear-cutting and wildfires on succession of ground beetle (Coleoptera: Carabidae) assemblages on the east slopes of the Rocky Mountains

2019 ◽  
Vol 2 ◽  
Author(s):  
Vincent Del Bel Belluz ◽  
David Langor ◽  
Jari Niemelä ◽  
John Spence
Keyword(s):  
Ground Beetle ◽  
Mineral Soil ◽  
Basal Area ◽  
Species Assemblages ◽  
Ground Vegetation ◽  
Clear Cut ◽  
Clear Cutting ◽  
Beetle Assemblages ◽  
Trees And Shrubs

We studied how carabid beetle assemblages in lodgepole pine stands have responded after clear-cut harvest and wildfires on an actively managed landscape ~20 km south of Hinton, Alberta, Canada. The work builds on and expands a previous study (Niemela et al. 1993) conducted 23-24 years earlier in many of the same stands sampled in the current study. Carabid species assemblages are compared along a chronosequence of stands ranging in age from 12 to 53 years after clear-cutting. Recovery of carabid assemblages toward pre-harvest structure in regenerating stands, as reflected in the 2013-14 data, appears to have progressed more rapidly than in equivalently aged stands from the earlier study. In addition, carabid species assemblages differed significantly between clear-cut and burned stands of comparable age in 2013-14, with assemblages of burned stands being more similar to the pre-harvest structure than in clear-cut stands. Ground vegetation, mineral soil cover and basal area of trees and shrubs were significantly correlated with structure of carabid species assemblages in young and old regenerating stands, suggesting that environmental and plant successional gradients drive patterns in carabid assemblages. However, assemblage differences between older burned and clear-cut stands indicate that the type of disturbance influences long-term carabid recovery. Relationships between these findings and issues related to conservation of biodiversity and climate change are discussed.

Physical activity and cognitive function in older persons

2016 ◽  
Vol 64 (2) ◽  
Keyword(s):  
Physical Activity ◽  
Cognitive Impairment ◽  
Cognitive Function ◽  
Executive Functions ◽  
Cognitive Aging ◽  
Clinical Studies ◽  
Older Persons ◽  
Positive Effects ◽  
Critical Challenge

Strategies to improve cognitive aging are highly needed. Among those, promotion of exercise and physical activity appears as one of the most attractive and beneficial intervention. Indeed, results from basic and clinical studies suggest that exercise and physical activity have positive effects on cognition in older persons without cognitive impairment, as well as in those with dementia. Despite inconsistent results, aerobic exercise appears to have the strongest potential to enhance cognition. However, even limited periods of walking (45 minutes, three times a week, over a 6-month period) have also been shown to enhance cognition, particularly executive functions. Changing long-term lifestyle habits in these older persons remains a critical challenge and attractive programs susceptible to gain adherence are needed to succeed in achieving improved cognitive aging.

Hallucinogen Use in College Students: Current Trends and Consequences of Use

2020 ◽  
Vol 9 (2) ◽  
pp. 115-127
Author(s):  
Lena S. Jia ◽  
Jessica A. Gold
Keyword(s):  
College Students ◽  
Drug Class ◽  
Positive Effects ◽  
Current Trends ◽  
College Population ◽  
Therapy Studies ◽  
Recreational Use ◽  
Perception Disorder ◽  
Review Current

Hallucinogens are a drug class that is growing in popularity with college students. Recent experimental trends, such as microdosing, have helped promote the use of hallucinogens on campus, and students may be tempted to use these substances due to their beliefs about the drugs’ positive effects on mood. Although hallucinogens are not currently an established form of medical therapy, studies have shown that they have significant benefits as adjunctive treatments for psychological disorders. However, the recreational use of these drugs in college students often occurs in uncontrolled doses or with drug mixing, which is often dangerous. Furthermore, students with mental health disorders may have their symptoms masked by hallucinogenic drug use, which could delay treatment and have serious consequences. Long-term use of these drugs may also result in tolerance or hallucinogen persisting perception disorder. This article attempts to review current information regarding hallucinogen use and how it applies to the college population.

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