scholarly journals Fuel mass and forest structure following stand-replacement fire and post-fire logging in a mixed-evergreen forest

2013 ◽  
Vol 22 (5) ◽  
pp. 652 ◽  
Author(s):  
Daniel C. Donato ◽  
Joseph B. Fontaine ◽  
J. Boone Kauffman ◽  
W. Douglas Robinson ◽  
Beverly E. Law
Keyword(s):  
High Intensity ◽  
Fire Hazard ◽  
Basal Area ◽  
Evergreen Forest ◽  
Moderate Intensity ◽  
Predictive Tool ◽  
Fuel Loads ◽  
Management Actions ◽  
Dead Trees ◽  
Standing Dead

Following severe wildfires, managing fire hazard by removing dead trees (post-fire logging) is an important issue globally. Data informing these management actions are relatively scarce, particularly how fuel loads differ by post-fire logging intensity within different environmental settings. In mixed-evergreen forests of Oregon, USA, we quantified fuel profiles 3–4 years after stand-replacement fire – assessing three post-fire logging intensities (0, 25–75, or >75% basal area cut) across two climatic settings (mesic coastal, drier interior). Stand-replacement fire consumed ~17% of aboveground biomass. Post-fire logging significantly reduced standing dead biomass, with high-intensity treatment leaving a greater proportion (28%) of felled biomass on site compared with moderate-intensity treatment (14%) because of less selective tree felling. A significant relationship between logging intensity and resulting surface fuels (per-hectare increase of 0.4–1.2Mg per square metre of basal area cut) indicated a broadly applicable predictive tool for management. Down wood cover increased by 3–5 times and became more spatially homogeneous after logging. Post-fire logging altered the fuel profile of early-seral stands (standing material removed or transferred, short-term increase in surface fuels, likely reduction in future large fuel accumulation), with moderate-intensity and unlogged treatments yielding surface fuel loads consistent with commonly prescribed levels, and high-intensity treatment resulting in greater potential need for follow-up fuel treatments.

scholarly journals Tree structure and richness in an Atlantic Forest fragment: distance from anthropogenic and natural edges

2009 ◽  
Vol 33 (6) ◽  
pp. 1123-1132 ◽  
Author(s):  
Maíra Taquiguthi Ribeiro ◽  
Flavio Nunes Ramos ◽  
Flavio Antonio Maës Dos Santos
Keyword(s):  
Atlantic Forest ◽  
Rio De Janeiro ◽  
Basal Area ◽  
The State ◽  
Forest Fragment ◽  
Dead Trees ◽  
Tree Communities ◽  
Standing Dead ◽  
Total Study Area ◽  
Tree Branch

Approximately 7.2% of the Atlantic rainforest remains in Brazil, with only 16% of this forest remaining in the State of Rio de Janeiro, all of it distributed in fragments. This forest fragmentation can produce biotic and abiotic differences between edges and the fragment interior. In this study, we compared the structure and richness of tree communities in three habitats - an anthropogenic edge (AE), a natural edge (NE) and the fragment interior (FI) - of a fragment of Atlantic forest in the State of Rio de Janeiro, Brazil (22°50'S and 42°28'W). One thousand and seventy-six trees with a diameter at breast height > 4.8 cm, belonging to 132 morphospecies and 39 families, were sampled in a total study area of 0.75 ha. NE had the greatest basal area and the trees in this habitat had the greatest diameter:height allometric coefficient, whereas AE had a lower richness and greater variation in the height of the first tree branch. Tree density, diameter, height and the proportion of standing dead trees did not differ among the habitats. There was marked heterogeneity among replicates within each habitat. These results indicate that the forest interior and the fragment edges (natural or anthropogenic) do not differ markedly considering the studied parameters. Other factors, such as the age from the edge, type of matrix and proximity of gaps, may play a more important role in plant community structure than the proximity from edges.

Prescribed burning of thinning slash in regrowth stands of jarrah (Eucalyptus marginata) following bauxite mining in south-west Australia

2010 ◽  
Vol 19 (6) ◽  
pp. 737 ◽  
Author(s):  
Andrew H. Grigg ◽  
Melanie A. Norman ◽  
Carl D. Grant
Keyword(s):  
Prescribed Burning ◽  
Fire Risk ◽  
Moderate Intensity ◽  
Eucalyptus Marginata ◽  
Bauxite Mining ◽  
Thinning Intensity ◽  
Fuel Loads ◽  
Fuel Layer ◽  
Standing Dead ◽  
Dead Vegetation

Prescribed burning of regrowth jarrah stands established after bauxite mining is key to their integration into standard jarrah forest management, but fire management in thinned regrowth stands has not been studied. Fuel loads in 10- to 13-year-old thinned regrowth increased exponentially with thinning intensity, doubling from 18 t ha–1 in untreated stands (1500–2500 stems ha–1) to 37.4 t ha–1 in the heaviest treatment (400 stems ha–1 retained); however, litter and standing dead vegetation were concentrated within 60 cm of the ground. Intensities of subsequent autumn prescribe-burns increased with increasing fuel loads, but all burns were typically of low to moderate intensity <1800 kW m–1. Three months post-burn, total fuel loads averaged 5 t ha–1, recovering after 4.5 years to 75% of pre-burn levels across all thinning treatments owing mostly to dense understorey regeneration. Where no burning occurred after thinning, total fuel loads declined to be comparable to the unthinned control after 4.5 years, averaging 20 t ha–1. Prescribed burns in autumn following thinning are not recommended because a dense well-aerated and elevated fuel layer is reinstated, posing a future fire risk. Burning 1–2 years before thinning may be an appropriate alternative strategy.

Comparison of snag densities among regeneration treatments in mixed pine–hardwood forests

2013 ◽  
Vol 43 (7) ◽  
pp. 619-626 ◽  
Author(s):  
Roger W. Perry ◽  
Ronald E. Thill
Keyword(s):  
Group Selection ◽  
Forest Regeneration ◽  
Forest Ecosystems ◽  
Basal Area ◽  
Timber Harvest ◽  
Hardwood Forests ◽  
Management Objectives ◽  
Dead Trees ◽  
Single Tree Selection ◽  
Standing Dead

Standing dead trees (snags) are an important component of forest ecosystems, providing foraging, nesting, and roosting substrate for a variety of vertebrates. We examined the effects of four forest regeneration treatments on residual snag density and compared those with densities found in unharvested, naturally regenerated forests (controls) during the second, fourth, and sixth year after timber harvest in mixed pine–hardwood forests of Arkansas and Oklahoma. Regeneration treatments were clearcut with snag creation, shelterwood, single-tree selection, and group selection. Density of large snags (≥25.0 cm DBH) differed only during the sixth year after harvest, with shelterwoods having a lower density of large snags (1.0 snags/ha) than the control or group selection stands (4.0 and 4.2 snags/ha, respectively). Density of small snags (10.0–24.9 cm DBH) mirrored residual basal area, with controls and group-selection stands having the greatest snag densities. Creation of snags in clearcuts by injection with herbicides caused initial snag density in these areas to be greater than other treatments, but density in clearcuts declined sharply by 6 years after harvest. In the absence of snag creation, treatments such as shelterwoods that remove most trees may have snag densities below that required to address some management objectives without additional snag creation.

scholarly journals Floristic and phytosociology in a physiognomic gradient of riverine forest in Cerrado, Campinas, SP

2013 ◽  
Vol 13 (3) ◽  
pp. 110-120 ◽  
Author(s):  
Marina Begali Carvalho ◽  
Luís Carlos Bernacci ◽  
Ricardo Marques Coelho
Keyword(s):  
Riparian Forest ◽  
Floristic Composition ◽  
Citrus Limon ◽  
Single Individual ◽  
Cerrado Vegetation ◽  
Riverine Forest ◽  
Management Actions ◽  
Riparian Species ◽  
Dead Trees ◽  
Standing Dead

Knowledge on floristic composition and vegetation structure is essential to preserve plant biodiversity and environmental conditions. A floristic and structural survey of woody vegetation was carried out in a physiognomic gradient of riparian forest of Cerrado vegetation, Campinas - SP. We sampled 25 plots, distributed along five transects, located perpendicularly to a stream. We found 971 individuals (65 standing dead trees) distributed among 35 families and 80 species. We recorded one single individual of exotic species (Citrus limon – rangpur) and a large number of individuals of endangered species (Luetzelburgia guaissara, Myroxylon peruiferum andTrichilia hirta) indicating that the Santa Elisa study area retains much of the original characteristics of its native vegetation. The small number of exclusive Cerrado species in the study area indicates that riverine environments represent a very different condition in relation to that of the Cerrado. Except for swampy areas, which are more homogeneous and floristically similar to each other due to adaptations to greater environmental constraints, the riverine forest physiognomies showed greater internal floristic heterogeneity, even considering only those located in Cerrado areas. This emphasizes the importance of studying riverine forests flora for each particular region, especially when restoration or management actions are needed. At the Santa Elisa riverine-cerrado transition fragment, riparian species were found throughout gradient up to the limit of the study area showing that a distance of at least 50 m far from the stream should be preserved in order to keep the riparian environment.

scholarly journals Snags and Down Wood in Missouri Old-Growth and Mature Second-Growth Forests

1997 ◽  
Vol 14 (4) ◽  
pp. 165-172 ◽  
Author(s):  
Stephen R. Shifley ◽  
Brian L. Brookshire ◽  
David R. Larsen ◽  
Laura A. Herbeck
Keyword(s):  
Size Distribution ◽  
Basal Area ◽  
Wildlife Habitat ◽  
Old Growth ◽  
Frequency Distributions ◽  
Dead Trees ◽  
Second Growth ◽  
Standing Dead ◽  
The Mean ◽  
Negative Exponential

Abstract As forest managers in the Midwest focus more attention toward understanding and maintaining ecosystem processes, greater emphasis is being placed on the role of snags and down wood in providing wildlife habitat, cycling nutrients, and maintaining continuity in forest structure following harvest. We measured five remnant old-growth hardwood tracts and six mature, second-growth, hardwood tracts in Missouri and compared findings concerning (1) the volume of down wood and (2) the number and size distribution of snags (i.e., standing dead trees). Volume of down wood ≥ 10 cm in diameter averaged 36 m³/ha on the old-growth tracts, double the 18 m³/ha mean volume for the second-growth sites. This difference in volume was concentrated in pieces of down wood with diameters larger than 20 cm; below diameters of 20 cm the number of pieces of down wood by diameter class was similar for the old-growth and second-growth sites. On the old-growth sites, the mean basal area of snags ≥ 10 cm dbh was 1.9 m²/ha. This was approximately 1.5 times greater than the mean basal area of snags on the second-growth sites. The number of snags ≥ 10 cm dbh on the old growth sites was approximately 9% pf the number of live trees on those sites. The corresponding value for second-growth sites was 8%. On both the old-growth and second-growth sites, the number of snags and the number of live trees by dbh class followed a negative exponential (reverse-J) form. Frequency distributions for the number of snags by dbh class closely followed those for live trees on the same sites. These results provide managers with general guidelines for the quantity of down wood likely to be found in mature second-growth forests and old-growth forests. We also provide some provisional rules of thumb for estimating the density and size distribution of snags from values observed for live trees in the same stand. North. J. Appl. For. 14(4):165-172.

Assessing and modeling standing deadwood attributes under alternative silvicultural regimes in the Acadian Forest region of Maine, USA

2012 ◽  
Vol 42 (11) ◽  
pp. 1873-1883 ◽  
Author(s):  
Matthew B. Russell ◽  
Laura S. Kenefic ◽  
Aaron R. Weiskittel ◽  
Joshua J. Puhlick ◽  
John C. Brissette
Keyword(s):  
Basal Area ◽  
Stand Density ◽  
Wildlife Habitat ◽  
Silvicultural Treatments ◽  
Forest Region ◽  
Dead Trees ◽  
Standing Dead ◽  
Standing Dead Trees ◽  
Modeling Strategy ◽  
Area And Volume

Estimating the amount of standing deadwood in forests is crucial for assessing wildlife habitat and determining carbon stocks. In this analysis, snags (standing dead trees) in various stages of decay were inventoried across eight silvicultural treatments in eastern spruce–fir forests in central Maine nearly 60 years after treatments were initiated. Several modeling strategies were developed to estimate number of snags per hectare in various stages of decay. An unmanaged reference area displayed the highest basal area and volume of snags (5.4 ± 3.1 m2·ha–1 and 29.4 ± 23.6 m3·ha–1, respectively, (mean ± standard deviation)), while the lowest basal area and volume (0.9 ± 1.0 m2·ha–1 and 3.1 ± 5.2 m3·ha–1) were observed in selection system with a 5-year cutting cycle. Models indicated that snag abundance was related to stand density, depth to water table, and the average harvest interval of the treatment. At a fixed stand density, approximately 140% more snags were predicted to occur in treatments with an average harvest interval of 55 compared with 5 years. An index of error reflecting the number of snags found in certain decay classes was reduced by 40% when predictions from count regression models fit with a mixed modeling strategy were used over ordinal regression. Results from these analyses can help to reduce the disparities between observed and modeled snag stocking levels and further our understanding of the relationships between live and standing dead trees inherent to eastern spruce–fir forests.

A Comparison of a Moderate with Moderate-high Intensity Oral Anticoagulant Treatment in Patients with Mechanical Heart Valve Prostheses

1997 ◽  
Vol 77 (05) ◽  
pp. 0839-0844 ◽  
Author(s):  
Vittorio Pengo ◽  
Fabio Barbero ◽  
Alberto Banzato ◽  
Elisabetta Garelli ◽  
Franco Noventa ◽  
...  
Keyword(s):  
Heart Valve ◽  
High Intensity ◽  
Oral Anticoagulant ◽  
Oral Anticoagulants ◽  
Mechanical Heart Valve ◽  
Moderate Intensity ◽  
Minor Bleeding ◽  
Anticoagulant Treatment ◽  
Oral Anticoagulant Treatment ◽  
Valve Prostheses

SummaryBackground. The long-term administration of oral anticoagulants to patients with mechanical heart valve prostheses is generally accepted. However, the appropriate intensity of oral anticoagulant treatment in these patients is still controversial.Methods and Results. From March 1991 to March 1994, patients referred to the Padova Thrombosis Center who had undergone mechanical heart valve substitution at least 6 months earlier were randomly assigned to receive oral anticoagulants at moderate intensity (target INR = 3) or moderate-high intensity (target INR = 4). Principal end points were major bleeding, thromboembolism and vascular death. Minor bleeding was a secondary end-point.A total of 104 patients were assigned to the target 3 group and 101 to the target 4 group; they were followed for from 1.5 years to up 4.5 years (mean, 3 years). Principal end-points occurred in 13 patients in the target 3 group (4 per 100 patient-years) and in 20 patients in the target 4 group (6.9 per 100 patient-years). Major hemorrhagic events occurred in 15 patients, 4 in the target 3 group (1.2 per 100 patient-years) and 11 in the target 4 group (3.8 per 100 patient-years) (p = 0.019). The 12 recorded episodes of thromboembolism, 4 of which consisted of a visual deficit, were all transient ischemic attacks, 6 in the target 3 group (1.8 per 100 patient-years) and 6 in the target 4 group (2.1 per 100 patient- years). There were 3 vascular deaths in each group (0.9 and 1 per 100 patient-years for target 3 and target 4 groups, respectively). Minor bleeding episodes occurred 85 times (26 per 100 patient-years) in the target 3 group and 123 times (43 per 100 patient-years) in the target 4 group (p = 0.001).Conclusions. Mechanical heart valve patients on anticoagulant treatment who had been operated on at least 6 months earlier experienced fewer bleeding complications when maintained on a moderate intensity regimen (target INR = 3) than those on a moderate-high intensity regimen (target INR = 4). The number of thromboembolic events and vascular deaths did not differ between the two groups.

Effects of High Intensity Statin Therapy in the Treatment of Diabetic Dyslipidemia in Patients with Coronary Artery Disease

2018 ◽  
Vol 24 (4) ◽  
pp. 427-441 ◽  
Author(s):  
Marija Vavlukis ◽  
Sasko Kedev
Keyword(s):  
Statin Therapy ◽  
High Intensity ◽  
Statistical Significance ◽  
Incident Diabetes ◽  
Moderate Intensity ◽  
Protective Effects ◽  
Pcsk9 Inhibitors ◽  
Diabetic Dyslipidemia ◽  
Patients With Diabetes

Background: Diabetic dyslipidemia has specifics that differ from dyslipidemia in patients without diabetes, which contributes to accelerated atherosclerosis equally as dysglycemia. The aim of this study was to deduce the interdependence of diabetic dyslipidemia and cardiovascular diseases (CVD), therapeutic strategies and the risk of diabetes development with statin therapy. Method: We conducted a literature review of English articles through PubMed, PubMed Central and Cochrane, on the role of diabetic dyslipidemia in atherosclerosis, the antilipemic treatment with statins, and the role of statin therapy in newly developed diabetes, by using key words: atherosclerosis, diabetes mellitus, diabetic dyslipidemia, CVD, statins, nicotinic acid, fibrates, PCSK9 inhibitors. Results: hyperglycemia and dyslipidemia cannot be treated separately in patients with diabetes. It seems that dyslipidemia plays one of the key roles in the development of atherosclerosis. High levels of TG, decreased levels of HDL-C and increased levels of small dense LDL- C particles in the systemic circulation are the most specific attributes of diabetic dyslipidemia, all of which originate from an inflated flux of free fatty acids occurring due to the preceding resistance to insulin, and exacerbated by elevated levels of inflammatory adipokines. Statins are a fundamental treatment for diabetic dyslipidemia, both for dyslipidemia and for CVD prevention. The use of statin treatment with high intensity is endorsed for all diabetes-and-CVD patients, while a moderate - intensity treatment can be applied to patients with diabetes, having additional risk factors for CVD. Statins alone are thought to possess a small, although of statistical significance, risk of incident diabetes, outweighed by their benefits. Conclusion: As important as hyperglycemia and glycoregulation are in CVD development in patients with diabetes, diabetic dyslipidemia plays an even more important role. Statins remain the cornerstone of antilipemic treatment in diabetic dyslipidemia, and their protective effects in CVD progression overcome the risk of statin- associated incident diabetes.

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