Pre-wildfire fuel reduction treatments result in more resilient forest structure a decade after wildfire

2013 ◽  
Vol 22 (8) ◽  
pp. 1108 ◽  
Author(s):  
Camille Stevens-Rumann ◽  
Kristen Shive ◽  
Peter Fulé ◽  
Carolyn H. Sieg
Keyword(s):  
Ponderosa Pine ◽  
Coarse Woody Debris ◽  
Stand Structure ◽  
Woody Debris ◽  
Fire Severity ◽  
Stand Density ◽  
Wildlife Habitat ◽  
Minimum Size ◽  
Forest Fuels ◽  
Ponderosa Pine Forests

Increasing size and severity of wildfires have led to an interest in the effectiveness of forest fuels treatments on reducing fire severity and post-wildfire fuels. Our objective was to contrast stand structure and surface fuel loadings on treated and untreated sites within the 2002 Rodeo–Chediski Fire area. Data from 140 plots on seven paired treated–untreated sites indicated that pre-wildfire treatments reduced fire severity compared with untreated sites. In 2011, coarse woody debris loading (woody material>7.62cm in diameter) was 257% higher and fine woody debris (woody material<7.62cm) was 152% higher on untreated sites than on treated sites. Yet, in spite of higher levels of coarse woody debris on untreated sites, loadings did not exceed recommended ranges based on published literature and many treated sites fell below recommendations. By 2011, basal area and stand density on treated sites and stand density on untreated sites met management guidelines for ponderosa pine forests, but untreated sites had basal areas well below recommendations. Snags declined over this period and only three plots had snags that met minimum size and density requirements for wildlife habitat by 2011. The effects of pre-wildfire treatments are long-lasting and contribute to changes in both overstorey and understorey fuel complexes.

Effect of thinning and prescribed burning on crown fire severity in ponderosa pine forests

2002 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Jolie Pollet ◽  
Philip N. Omi
Keyword(s):  
Prescribed Fire ◽  
Ponderosa Pine ◽  
Stand Structure ◽  
Fire Severity ◽  
Fire Effects ◽  
Pine Forests ◽  
Crown Fire ◽  
Fuel Treatments ◽  
Ponderosa Pine Forests ◽  
Wildfire Hazard

Fire exclusion policies have affected stand structure and wildfire hazard in north American ponderosa pine forests. Wildfires are becoming more severe in stands where trees are densely stocked with shade-tolerant understory trees. Although forest managers have been employing fuel treatment techniques to reduce wildfire hazard for decades, little scientific evidence documents the success of treatments in reducing fire severity. Our research quantitatively examined fire effects in treated and untreated stands in western United States national forests. Four ponderosa pine sites in Montana, Washington, California and Arizona were selected for study. Fuel treatments studied include: prescribed fire only, whole-tree thinning, and thinning followed by prescribed fire. On-the-ground fire effects were measured in adjacent treated and untreated forests. We developed post facto fire severity and stand structure measurement techniques to complete field data collection. We found that crown fire severity was mitigated in stands that had some type of fuel treatment compared to stands without any treatment. At all four of the sites, the fire severity and crown scorch were significantly lower at the treated sites. Results from this research indicate that fuel treatments, which remove small diameter trees, may be beneficial for reducing crown fire hazard in ponderosa pine sites.

Detection and Quantification of Coarse Woody Debris in Natural Forest Stands Using Airborne LiDAR

2021 ◽  
Author(s):  
Lukas R Jarron ◽  
Nicholas C Coops ◽  
William H MacKenzie ◽  
Pamela Dykstra
Keyword(s):  
Coarse Woody Debris ◽  
Laser Scanning ◽  
Stand Structure ◽  
Woody Debris ◽  
Large Diameter ◽  
Natural Forest ◽  
Wildlife Habitat ◽  
Airborne Lidar ◽  
Forest Stands ◽  
Linear Pattern

Abstract Coarse woody debris (CWD) is a meaningful contributor to forest carbon cycles, wildlife habitat, and biodiversity and can influence wildfire behavior. Using airborne laser scanning (ALS), we map CWD across a range of natural forest stand types in north-central British Columbia, Canada, providing forest managers with spatially detailed information on the presence and volume of ground-level woody biomass. We describe a novel methodology that isolates CWD returns from large diameter logs (&gt;30cm) using a refined grounding algorithm, a mixture of height and pulse-based filters and linear pattern recognition, to transform ALS returns into measurable, vectorized shapes. We then assess the accuracy of CWD detection at the individual log level and predict CWD volume at the plot level. We detected 64% of CWD logs and 79% of CWD volume within our plots. Increased elevation of CWD significantly aided detection (P = 0.04), whereas advanced stages of decay hindered detection (P = 0.04). ALS-predicted CWD volume totals were compared against field-measured CWD and displayed a strong correlation (R = 0.81), allowing us to expand the methodology to map CWD over a larger region. The expanded CWD volume map compared ALS volume predictions between stands and suggests greater volume in stands with older and more heterogeneous stand structure. Study Implications A methodology is presented to extract returns associated with large diameter coarse woody debris (CWD) directly from an ALS point cloud. These returns are transformed into measurable shapes and their volume estimated based on the height of the returns. The procedure is implemented over a large forested area to produce a map of local CWD volume. Production of these maps can be used to generate inventory of CWD over a range of natural forest stands to support a more well-rounded understanding of carbon levels associated with downed trees, wildlife habitat attributes, and fuel loading in the terrestrial biosphere.

An assessment of expert-based marten habitat models used for forest management in Ontario

2005 ◽  
Vol 81 (6) ◽  
pp. 801-807 ◽  
Author(s):  
Jeff Bowman ◽  
Jean-François Robitaille
Keyword(s):  
Habitat Suitability ◽  
Coarse Woody Debris ◽  
Stand Structure ◽  
Woody Debris ◽  
Abies Balsamea ◽  
Wildlife Habitat ◽  
Habitat Model ◽  
Stand Age ◽  
Habitat Models ◽  
Development Stages

We used marten snow tracking data and a previously developed empirical habitat model from northeastern Ontario to validate a number of expert-based, non-spatial marten habitat models. In particular, we tested the non-spatial Ontario Wildlife Habitat Analysis Model, the Boreal East Habitat Suitability Matrix (including tests of both standard forest units and development stages), and Allen's (1982) HSI model. Marten habitat use as measured by tracks in the snow was consistent with predictions of all the expert-based models, suggesting that these models correctly characterized the stand-level forest cover selected by marten in winter. Suitability ranks for individual stands derived from standard forest units and development stages also were consistent with their use by marten. The empirical model was consistent with the expert-based models in that it considered suitable forest stands to be those with tall trees dominated by spruce (Picea spp.) and balsam fir (Abies balsamea) trees, with a large amount of coarse woody debris, and high canopy closure. Our findings suggested that the expert-based models were able to characterize stand structure used by marten despite some of the models using only inputs available from stand inventories. This was accomplished because stand structural elements such as coarse woody debris were integrated into OWHAM and HSM indirectly, through relationships with stand age and species composition. Key words: boreal forest, forest inventory, habitat, habitat suitability, guidelines, Forest Ecosystem Classification, landscape, Martes americana, resource selection, snow tracking, spatial autocorrelation, stand structure

Short-term impact of post-fire salvage logging on regeneration, hazardous fuel accumulation, and understorey development in ponderosa pine forests of the Black Hills, SD, USA

2009 ◽  
Vol 18 (4) ◽  
pp. 451 ◽  
Author(s):  
Tara L. Keyser ◽  
Frederick W. Smith ◽  
Wayne D. Shepperd
Keyword(s):  
Ponderosa Pine ◽  
Tree Mortality ◽  
Woody Debris ◽  
Fire Severity ◽  
Plant Cover ◽  
Black Hills ◽  
Understorey Vegetation ◽  
Salvage Logging ◽  
Ponderosa Pine Forests ◽  
Fuel Accumulation

We examined the impacts of post-fire salvage logging on regeneration, fuel accumulation, and understorey vegetation and assessed whether the effects of salvage logging differed between stands burned under moderate and high fire severity following the 2000 Jasper Fire in the Black Hills. In unsalvaged sites, fire-related tree mortality created a large standing pool of available fuel, resulting in a rapid increase in surface fuel loads. After 5 years, fine woody debris (FWD) and coarse woody debris (CWD) increased ~1380% and 980% in unsalvaged sites, resulting in FWD and CWD loads of 13 and 25 Mg ha–1, respectively. In contrast, salvage logging limited the rate of accumulation of FWD to ~110% over the same time period and total accumulation of CWD to 16 Mg ha–1. In moderate-severity sites, regeneration was 75% lower in salvaged sites owing to low seed-tree retention, suggesting a re-evaluation of salvage guidelines during future operations in the Black Hills. The likelihood of timely regeneration in high-severity sites, regardless of salvage treatment, is low. We found no discernible effect of salvage logging on understorey development 5 years after fire. Logging caused neither a reduction in total plant cover nor an increase in the abundance of exotic species.

scholarly journals Forest stand structure and coarse woody debris determine the biodiversity of beetle communities in Mediterranean mountain beech forests

2021 ◽  
pp. e01637
Author(s):  
Francesco Parisi ◽  
Michele Innangi ◽  
Roberto Tognetti ◽  
Fabio Lombardi ◽  
Gherardo Chirici ◽  
...  
Keyword(s):  
Coarse Woody Debris ◽  
Stand Structure ◽  
Woody Debris ◽  
Forest Stand ◽  
Beech Forests ◽  
Forest Stand Structure

scholarly journals Limited Effects of Long-Term Repeated Season and Interval of Prescribed Burning on Understory Vegetation Compositional Trajectories and Indicator Species in Ponderosa Pine Forests of Northeastern Oregon, USA

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 834
Author(s):  
Harold S. J. Zald ◽  
Becky K. Kerns ◽  
Michelle A. Day
Keyword(s):  
Indicator Species ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Vascular Plant ◽  
Fire Behavior ◽  
Understory Vegetation ◽  
Forest Composition ◽  
Forest Fuels ◽  
Ponderosa Pine Forests ◽  
Over Time

Fire exclusion has dramatically altered historically fire adapted forests across western North America. In response, forest managers reduce forest fuels with mechanical thinning and/or prescribed burning to alter fire behavior, with additional objectives of restoring forest composition, structure, and ecosystem processes. There has been extensive research on the effects of fuel reduction and restoration treatments on trees, fuels, regeneration, and fire behavior; but less is known about how these treatments influence understory vegetation, which contains the majority of vascular plant diversity in many dry conifer forests. Of particular interest is how understory vegetation may respond to the season and interval of prescribed burning. The season and interval of prescribed burning is often determined by operational constraints rather than historical fire regimes, potentially resulting in fire conditions and burn intervals to which native plants are poorly adapted. In this study, we examined how understory vegetation has responded to season and interval of prescribed burning in ponderosa pine (Pinus ponderosa) forests in the Blue Mountains of northeastern Oregon, USA. Using over a decade (2002–2015) of understory vegetation data collected in stands with different intervals (5 versus 15 year) and seasons (spring versus fall) of prescribed burning, we quantified how season and interval of prescribed burning has influenced understory vegetation compositional trajectories and indicator species over time. Season of prescribed burning resulted in different understory communities and distinct trajectories of understory composition over time, but interval of burning did not. Indicator species analysis suggests fall burning is facilitating early seral species, with native annual forbs displaying ephemeral responses to frequent burning, while invasive cheatgrass (Bromus tectorum) increased in abundance and frequency across all treatments over time. These findings indicate that understory vegetation in these ecosystems are sensitive to seasonality of burning, but the responses are subtle. Our findings suggest season and interval of prescribed burning used in this study do not result in large changes in understory vegetation community composition, a key consideration as land managers increase the pace and scale of prescribed fire in these forests.

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.

Post-fire soil fluxes of CO2, CH4 and N2O along the Colorado Front Range

2011 ◽  
Vol 20 (7) ◽  
pp. 838 ◽  
Author(s):  
Mark A. Gathany ◽  
Ingrid C. Burke
Keyword(s):  
Soil Moisture ◽  
Ponderosa Pine ◽  
Fire Severity ◽  
Colorado Front Range ◽  
Front Range ◽  
Soil Co2 Flux ◽  
Ponderosa Pine Forests ◽  
Time Since Fire ◽  
Wide Range ◽  
Ch4 And N2o

Wildfires affect Rocky Mountain ecosystems across a wide range of spatial and temporal scales. Many of the resulting changes are greatest for environmental factors, such as substrate and microclimate that control exchanges of greenhouse gases. We investigated this link to understand how time since fire influences the cycling of these gases through ponderosa pine forests. We measured and compared trace gas flux rates between recently burned sites and topographical aspects (north- and south-facing slopes). We calculated the ability of five factors (soil temperature, soil moisture, fire severity, aspect and time since fire) to describe the variability in the flux rates. Our study revealed that carbon dioxide (CO2) fluxes were significantly different between sites; however, methane (CH4) uptake was not different between sites or aspects. Nitrous oxide (N2O) fluxes had a significant interaction between site and aspect. Using a likelihood approach, we determined the strength of support in the data for model combinations of five variables. Of these, the single variable models soil moisture, time since fire and severity best described the CO2, CH4, and N2O flux data respectively. Our data show that following a forest fire in the Colorado Front Range, >98% of the global warming potential of the measured soil–atmosphere fluxes is contributed by the soil CO2 flux.

Dwarf mistletoe effects on fuel loadings in ponderosa pine forests in northern Arizona

2007 ◽  
Vol 37 (3) ◽  
pp. 662-670 ◽  
Author(s):  
Chad Hoffman ◽  
Robert Mathiasen ◽  
Carolyn Hull Sieg
Keyword(s):  
Ponderosa Pine ◽  
Fire Behavior ◽  
Fuel Loading ◽  
Dwarf Mistletoe ◽  
Forest Fuels ◽  
Ponderosa Pine Forests ◽  
Northern Arizona ◽  
Basaltic Soils ◽  
Four Levels ◽  
Fuels Treatments

Southwestern dwarf mistletoe ( Arceuthobium vaginatum (Willd.) J. Presl ssp. cryptopodum ) infests about 0.9 million ha in the southwestern United States. Several studies suggest that dwarf mistletoes affect forest fuels and fire behavior; however, few studies have quantified these effects. We compared surface fuel loadings and predicted fire behavior among four levels of dwarf mistletoe infestation (none, light, moderate, and severe) in a total of 239 plots on 11 sites on basaltic soils in northern Arizona. In each plot we measured tree attributes, dwarf mistletoe rating and surface fuel loading. Stands severely infested by dwarf mistletoe had lower (P < 0.05) tree density and higher snag density, but higher (P < 0.05) total surface fuel loadings and total fuel loadings >7.62 cm and <7.62 cm, than non-infested stands. However, there were no statistical differences in any canopy fuel variables among infestation classes. Predicted fire behavior indicated that the wind speed required to promote the spread of a surface fire into the canopy was lower in severely infested stands than in non-infested stands. These results suggest that stands in northern Arizona that are severely infested with dwarf mistletoe should be priority areas for fuels treatments.

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