Orchid abundance in hemiboreal forests: stand-scale effects of clear-cutting, green-tree retention, and artificial drainage

2011 ◽  
Vol 41 (6) ◽  
pp. 1352-1358 ◽  
Author(s):  
Asko Lõhmus ◽  
Tiiu Kull
Keyword(s):  
Scale Effects ◽  
Current Knowledge ◽  
Timber Harvesting ◽  
Clear Cutting ◽  
Artificial Drainage ◽  
Tree Retention ◽  
Green Tree Retention ◽  
Retention Trees ◽  
The Impact ◽  
Site Types

The current knowledge on the impact of forest management on plant species of conservation concern is poor. We asked how three basic silvicultural techniques (clear-cutting, green-tree retention, and artificial drainage) affect the abundance of terrestrial orchid species and their communities in Estonia, hemiboreal Europe. Fixed-area, fixed-effort surveys (4 h per 2 ha plot) were used in 29 plot clusters representing five site types, with each cluster including plots of four treatments (old growth, mature managed forest, and cutover with and without live retention trees). Altogether 11 species of orchids were recorded in those 116 plots, with the most complete sets of species in artificially drained plots and mature stands. Five species were widely distributed among treatments and site types, but most site types also hosted shade-tolerant orchids (six species) that characteristically disappeared after timber harvesting. Cutover areas (3–7 years after harvest) hosted no species absent from uncut forest stands, and retention of solitary trees had no effect on orchid abundance over clear-cuts. Modern Estonian forest landscapes appear to support viable populations of many orchids, with rotation ages sufficient for population development of the majority of shade-tolerant species.

For what, when, and where is green-tree retention better than clear-cutting? A review of the biodiversity aspects

2008 ◽  
Vol 255 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Raul Rosenvald ◽  
Asko Lõhmus
Keyword(s):  
Clear Cutting ◽  
Tree Retention ◽  
Green Tree Retention ◽  
Better Than

scholarly journals Ecosystem Management of Eastern Canadian Boreal Forests: Potential Impacts on Wind Damage

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 578
Author(s):  
Jean-Claude Ruel
Keyword(s):  
Ecosystem Management ◽  
Management Practices ◽  
Fire Regime ◽  
Management Strategies ◽  
Wind Damage ◽  
Old Growth ◽  
Partial Cutting ◽  
Tree Retention ◽  
Green Tree Retention ◽  
The Impact

Research Highlights: Windthrow can interfere significantly with ecosystem management practices. In some cases, their goal could still be reached but this may prove more complex in other cases, like the partial cutting of old-growth stands. In situations where windthrow is common without any human intervention, the use of partial cutting to maintain some stand structures may lead to a feedback loop leading to additional windthrow. Background and Objectives: Forest ecosystem management using natural disturbances as a template has become the management paradigm in many regions. Most of the time, the focus is on fire regime and effects. However, windthrow can be common in some places or can interfere with practices implemented in an ecosystem management strategy. This paper looks at interactions between ecosystem management and windthrow. Materials and Methods: The paper builds on three case studies looking at various elements that could be part of ecosystem management strategies. The first one looks at the impact of green tree retention, while the second one looks at the impact of reducing the size and dispersing clearcuts, and the last one examines the impact of a range of cutting practices in irregular old-growth stands. Results: Green tree retention leads to increased windthrow, especially when applied within mature even-aged stands. Reducing the size of clearcuts and dispersing them over the landscape also involves substantial windthrow along edges. Partial cutting in old-growth stands can lead to relatively high mortality, but part of it is not necessarily related to wind since it occurs as standing dead trees. Differences in the amount of damage with tree size and species have been found and could be used to reduce wind damage. Conclusions: Approaches to minimize wind damage in ecosystem management can be designed using existing knowledge. However, using windthrow as a template to design management strategies would prove more complex.

scholarly journals Green tree retention enhances negative short-term effects of clear-cutting on enchytraeid assemblages in a temperate forest

2019 ◽  
Vol 136 ◽  
pp. 106-115 ◽  
Author(s):  
Gergely Boros ◽  
Bence Kovács ◽  
Péter Ódor
Keyword(s):  
Temperate Forest ◽  
Short Term ◽  
Clear Cutting ◽  
Tree Retention ◽  
Green Tree Retention ◽  
Short Term Effects

Lichen assemblages on Scots pine stumps and fine woody debris in hemiboreal post-harvest sites: the impact of site age and green tree retention

Nova Hedwigia ◽  
2019 ◽  
Vol 109 (1) ◽  
pp. 247-266 ◽  
Author(s):  
Rolands Moisejevs ◽  
Jurga Motiejūnaité ◽  
Piret Lõhmus
Keyword(s):  
Scots Pine ◽  
Woody Debris ◽  
Post Harvest ◽  
Fine Woody Debris ◽  
Tree Retention ◽  
Green Tree Retention ◽  
The Impact

Influence of partial cutting on site microclimate, soil nitrogen dynamics, and microbial biomass in Douglas-fir stands in western Washington

1999 ◽  
Vol 29 (6) ◽  
pp. 705-713 ◽  
Author(s):  
Amy K Barg ◽  
Robert L Edmonds
Keyword(s):  
Soil Moisture ◽  
Microbial Biomass ◽  
N Mineralization ◽  
Partial Cutting ◽  
Total N ◽  
Soil Microbial ◽  
Clear Cutting ◽  
Tree Retention ◽  
Soil Temperatures ◽  
Green Tree Retention

Partial cutting as an alternative to clear-cutting is being practiced in many Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands in the Pacific Northwest United States. The objectives of this study were to determine the influence of (i) partial cutting (dispersed green-tree retention) and clear-cutting on air and soil temperatures and soil moisture, on surface mineral soil net ammonification, nitrification, and total N mineralization rates, and on soil microbial biomass and (ii) the proximity to trees in the green-tree retention areas on these factors. The study was conducted in 60- to 70-year-old stands in the Cedar River Watershed, about 70 km southeast of Seattle, Wash., between July 1994 and August 1995. Air and soil temperatures and soil moisture in the green-tree retention treatments were generally intermediate between the uncut forest and the clearcut treatments. There were no significant differences in net ammonification, nitrification, and total N mineralization rates and in soil microbial biomass among treatments. Soil moisture influenced net ammonification and total N mineralization rates and microbial biomass. Nitrogen dynamics were generally not influenced by nearness to trees in the green-tree retention treatment. Average microbial biomass, however, was higher near to green trees (1 m) than far (6 m).

Effects of partial cutting on the ectomycorrhizae of Picea glauca forests in northwestern Alberta

2005 ◽  
Vol 35 (6) ◽  
pp. 1442-1454 ◽  
Author(s):  
Lance W Lazaruk ◽  
Gavin Kernaghan ◽  
S Ellen Macdonald ◽  
Damase Khasa
Keyword(s):  
Picea Glauca ◽  
Effective Means ◽  
White Spruce ◽  
Root Tip ◽  
Root Tips ◽  
Partial Cutting ◽  
Disturbance Intensity ◽  
Tree Retention ◽  
Green Tree Retention ◽  
The Impact

This study assessed the impact of various harvesting practices (including those designed to emulate natural disturbances) on ectomycorrhizae (ECM) associated with white spruce (Picea glauca (Moench) Voss) in northwestern Alberta, Canada. Treatments included clearcuts, partial cuts (dispersed green-tree retention with 20%, 50%, and 75% residual live trees, and aggregated green-tree retention), unharvested control sites, and a burned stand. The percentage of active white spruce root tips and ECM richness and diversity, as observed in soil cores collected throughout the study site, all decreased with increasing disturbance intensity. Effects were particularly pronounced in clearcuts, machine corridors used for access by harvesting equipment in the dispersed green-tree retention stands, and in burned areas. Reductions in ECM biodiversity could be attributed to the sensitivity of late-stage ectomycorrhizae (e.g., Cortinarius spp., Lactarius spp., and Russula spp.) to soil disturbances and changes in microclimate associated with harvesting or burning. Areas of dispersed and aggregated green-tree retention were not dramatically different than unharvested forest in terms of root tip density and ECM richness, diversity, and composition. Harvesting practices that retain a percentage of residual live trees, either dispersed throughout the cutting unit or in aggregated patches, could be an effective means of maintaining ectomycorrhizal biodiversity at the stand level.

scholarly journals Urban Fire Severity and Vegetation Dynamics in Southern California

2020 ◽  
Vol 13 (1) ◽  
pp. 19
Author(s):  
Lauren E. H. Mathews ◽  
Alicia M. Kinoshita
Keyword(s):  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Current Knowledge ◽  
Fire Severity ◽  
Satellite Image ◽  
Burn Severity ◽  
Native Vegetation ◽  
Riparian Areas ◽  
The Impact

A combination of satellite image indices and in-field observations was used to investigate the impact of fuel conditions, fire behavior, and vegetation regrowth patterns, altered by invasive riparian vegetation. Satellite image metrics, differenced normalized burn severity (dNBR) and differenced normalized difference vegetation index (dNDVI), were approximated for non-native, riparian, or upland vegetation for traditional timeframes (0-, 1-, and 3-years) after eleven urban fires across a spectrum of invasive vegetation cover. Larger burn severity and loss of green canopy (NDVI) was detected for riparian areas compared to the uplands. The presence of invasive vegetation affected the distribution of burn severity and canopy loss detected within each fire. Fires with native vegetation cover had a higher severity and resulted in larger immediate loss of canopy than fires with substantial amounts of non-native vegetation. The lower burn severity observed 1–3 years after the fires with non-native vegetation suggests a rapid regrowth of non-native grasses, resulting in a smaller measured canopy loss relative to native vegetation immediately after fire. This observed fire pattern favors the life cycle and perpetuation of many opportunistic grasses within urban riparian areas. This research builds upon our current knowledge of wildfire recovery processes and highlights the unique challenges of remotely assessing vegetation biophysical status within urban Mediterranean riverine systems.

scholarly journals Effects of the Marine Biotoxins Okadaic Acid and Dinophysistoxins on Fish

2021 ◽  
Vol 9 (3) ◽  
pp. 293
Author(s):  
Mauro Corriere ◽  
Lucía Soliño ◽  
Pedro Reis Costa
Keyword(s):  
Okadaic Acid ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Current Knowledge ◽  
Global Climate ◽  
Scientific Evidence ◽  
Shellfish Poisoning ◽  
Morphological Alterations ◽  
The Impact ◽  
Dsp Toxins

Natural high proliferations of toxin-producing microorganisms in marine and freshwater environments result in dreadful consequences at the socioeconomically and environmental level due to water and seafood contamination. Monitoring programs and scientific evidence point to harmful algal blooms (HABs) increasing in frequency and intensity as a result of global climate alterations. Among marine toxins, the okadaic acid (OA) and the related dinophysistoxins (DTX) are the most frequently reported in EU waters, mainly in shellfish species. These toxins are responsible for human syndrome diarrhetic shellfish poisoning (DSP). Fish, like other marine species, are also exposed to HABs and their toxins. However, reduced attention has been given to exposure, accumulation, and effects on fish of DSP toxins, such as OA. The present review intends to summarize the current knowledge of the impact of DSP toxins and to identify the main issues needing further research. From data reviewed in this work, it is clear that exposure of fish to DSP toxins causes a range of negative effects, from behavioral and morphological alterations to death. However, there is still much to be investigated about the ecological and food safety risks related to contamination of fish with DSP toxins.

scholarly journals Phony peach disease: past and present impact on the peach industry in the southeastern U.S.A

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Kendall A. Johnson ◽  
Clive H. Bock ◽  
Phillip M. Brannen
Keyword(s):  
New Technologies ◽  
Current Knowledge ◽  
Future Research ◽  
Management Options ◽  
Disease Epidemiology ◽  
Pathogen Diversity ◽  
Foundational Research ◽  
Global Threat ◽  
And Control ◽  
The Impact

Abstract Background Phony peach disease (PPD) is caused by the plant pathogenic bacterium Xylella fastidiosa subsp. multiplex (Xfm). Historically, the disease has caused severe yield loss in Georgia and elsewhere in the southeastern United States, with millions of PPD trees being removed from peach orchards over the last century. The disease remains a production constraint, and management options are few. Limited research has been conducted on PPD since the 1980s, but the advent of new technologies offers the opportunity for new, foundational research to form a basis for informed management of PPD in the U.S. Furthermore, considering the global threat of Xylella to many plant species, preventing import of Xfm to other regions, particularly where peach is grown, should be considered an important phytosanitary endeavor. Main topics We review PPD, its history and impact on peach production, and the eradication efforts that were conducted for 42 years. Additionally, we review the current knowledge of the pathogen, Xfm, and how that knowledge relates to our understanding of the peach—Xylella pathosystem, including the epidemiology of the disease and consideration of the vectors. Methods used to detect the pathogen in peach are discussed, and ramifications of detection in relation to management and control of PPD are considered. Control options for PPD are limited. Our current knowledge of the pathogen diversity and disease epidemiology are described, and based on this, some potential areas for future research are also considered. Conclusion There is a lack of recent foundational research on PPD and the associated strain of Xfm. More research is needed to reduce the impact of this pathogen on peach production in the southeastern U.S., and, should it spread internationally, wherever peaches are grown.

scholarly journals Going “Green” in the Prevention and Management of Atherothrombotic Diseases: The Role of Dietary Polyphenols

2021 ◽  
Vol 10 (7) ◽  
pp. 1490
Author(s):  
Ana Reis ◽  
Sara Rocha ◽  
Victor de Freitas
Keyword(s):  
Risk Factors ◽  
Fruits And Vegetables ◽  
Current Knowledge ◽  
Cholesterol Biosynthesis ◽  
Dietary Polyphenols ◽  
Nutritional Strategy ◽  
Flavonoid Intake ◽  
Health Promoting ◽  
Socio Economic Impact ◽  
The Impact

During the 20th century processed and ready-to-eat foods became routinely consumed resulting in a sharp rise of fat, salt, and sugar intake in people’s diets. Currently, the global incidence of obesity, raised blood lipids, hypertension, and diabetes in an increasingly aged population contributes to the rise of atherothrombotic events and cardiovascular diseases (CVD) mortality. Drug-based therapies are valuable strategies to tackle and help manage the socio-economic impact of atherothrombotic disorders though not without adverse side effects. The inclusion of fresh fruits and vegetables rich in flavonoids to human diets, as recommended by WHO offers a valuable nutritional strategy, alternative to drug-based therapies, to be explored in the prevention and management of atherothrombotic diseases at early stages. Though polyphenols are mostly associated to color and taste in foods, food flavonoids are emerging as modulators of cholesterol biosynthesis, appetite and food intake, blood pressure, platelet function, clot formation, and anti-inflammatory signaling, supporting the health-promoting effects of polyphenol-rich diets in mitigating the impact of risk factors in atherothrombotic disorders and CVD events. Here we overview the current knowledge on the effect of polyphenols particularly of flavonoid intake on the atherothrombotic risk factors and discuss the caveats and challenges involved with current experimental cell-based designs.

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