Modeling Smoldering Emissions From Prescribed Broadcast Burns in the Pacific-Northwest

1994 ◽  
Vol 4 (3) ◽  
pp. 135 ◽  
Author(s):  
SA Ferguson ◽  
CC Hardy
Keyword(s):  
Pacific Northwest ◽  
Exponential Decay ◽  
Prescribed Burning ◽  
Field Measurements ◽  
Timber Harvest ◽  
Production Model ◽  
Total Biomass ◽  
Fuel Loading ◽  
Pollution Impacts ◽  
Improved Model

The objective of this study was to improve a smoke emissions model that is currently being used to help reduce pollution impacts from prescribed burning of timber harvest residues. Smoke emissions from these types of burns have been characterized with in situ, real time sampling packages. When emissions flux data from these sampling packages were compared with an existing emissions production model, it was found that the variety of rate characteristics for smoldering combustion caused by different burning conditions were not adequately described by the model. Therefore, we used the acquired data to develop an improved model for the early smoldering portion of broadcast prescribed fires. First, the data were compared with field measurements of pre-burn fuel loading, fuel moisture, and calculated biomass consumption. A linear relation was found between total biomass consumption and a rate constant for the exponential decay of smoldering emissions. The resulting regression equation was compared with observed data from previous studies and found to adequately predict an exponential decay constant, which is used to describe the early smoldering portion of harvest residue burns.

scholarly journals Impacts of Alternative Harvesting and Natural Disturbance Scenarios on Forest Biomass in the Superior National Forest, USA

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 491 ◽  
Author(s):  
Matthew Russell ◽  
Stephanie Patton ◽  
David Wilson ◽  
Grant Domke ◽  
Katie Frerker
Keyword(s):  
Forest Management ◽  
Forest Biomass ◽  
Natural Disturbance ◽  
Timber Harvest ◽  
Timber Harvesting ◽  
Volume Control ◽  
National Forest ◽  
Total Biomass ◽  
Natural Disturbances ◽  
Project Area

The amount of biomass stored in forest ecosystems is a result of past natural disturbances, forest management activities, and current structure and composition such as age class distributions. Although natural disturbances are projected to increase in their frequency and severity on a global scale in the future, forest management and timber harvesting decisions continue to be made at local scales, e.g., the ownership or stand level. This study simulated potential changes in natural disturbance regimes and their interaction with timber harvest goals across the Superior National Forest (SNF) in northeastern Minnesota, USA. Forest biomass stocks and stock changes were simulated for 120 years under three natural disturbance and four harvest scenarios. A volume control approach was used to estimate biomass availability across the SNF and a smaller project area within the SNF (Jeanette Project Area; JPA). Results indicate that under current harvest rates and assuming disturbances were twice that of normal levels resulted in reductions of 2.62 to 10.38% of forest biomass across the four primary forest types in the SNF and JPA, respectively. Under this scenario, total biomass stocks remained consistent after 50 years at current and 50% disturbance rates, but biomass continued to decrease under a 200%-disturbance scenario through 120 years. In comparison, scenarios that assumed both harvest and disturbance were twice that of normal levels and resulted in reductions ranging from 14.18 to 29.85% of forest biomass. These results suggest that both natural disturbances and timber harvesting should be considered to understand their impacts to future forest structure and composition. The implications from simulations like these can provide managers with strategic approaches to determine the economic and ecological outcomes associated with timber harvesting and disturbances.

scholarly journals Improving the Accuracy of a Hygrothermal Model for Wood-Frame Walls: A Cold-Climate Study

Buildings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 236
Author(s):  
Charles R. Boardman ◽  
Samuel V. Glass
Keyword(s):  
Field Study ◽  
Material Property ◽  
Oriented Strand Board ◽  
Field Measurements ◽  
Cold Climate ◽  
Latex Paint ◽  
Kraft Paper ◽  
Humidity Measurements ◽  
Wood Frame ◽  
Improved Model

A one-dimensional transient hygrothermal model was used to simulate eight different wood-frame wall assemblies. Simulations were compared with measured results from a two-year field study exploring the effects of exterior insulation on wall moisture performance in a cold-climate. The field study documented the moisture content, temperature, and relative humidity measurements in wall assemblies using oriented strand board (OSB) sheathing. Simulations were performed using generic design input values as well as input values based on measurements or sensitivity analysis. Laboratory material property measurements informed the choice of material property values in the improved model for OSB, asphalt-coated kraft paper, and interior latex paint. Simulations using improved input values typically agreed with field measurements within measurement error. The most significant model improvements were all related to vapor permeance. The vinyl siding used an effective permeance much lower than typically recommended. However, both the extruded polystyrene insulation and the asphalt-coated kraft paper facing on the cavity fiberglass insulation had higher permeance than literature values.

Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest

2006 ◽  
Vol 15 (1) ◽  
pp. 37 ◽  
Author(s):  
Eric E. Knapp ◽  
Jon E. Keeley
Keyword(s):  
Sierra Nevada ◽  
Prescribed Burning ◽  
Fire Severity ◽  
Basal Area ◽  
Conifer Forest ◽  
Fuel Loading ◽  
Early Season ◽  
Late Season ◽  
Fuel Loads ◽  
In Fire

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.

Chaparral growth-ring analysis as an indicator of stand biomass development

2016 ◽  
Vol 25 (10) ◽  
pp. 1086 ◽  
Author(s):  
Kellie A. Uyeda ◽  
Douglas A. Stow ◽  
John F. O'Leary ◽  
Christina Tague ◽  
Philip J. Riggan
Keyword(s):  
Growth Ring ◽  
Basal Area ◽  
Biomass Accumulation ◽  
Field Measurements ◽  
Solar Irradiation ◽  
Annual Precipitation ◽  
Total Biomass ◽  
Growth Rings ◽  
Close Relationship ◽  
Long Time

Chaparral wildfires typically create even-aged stands of vegetation that grow quickly in the first 2 decades following a fire. Patterns of this growth are important for understanding ecosystem productivity and re-establishment success, but are logistically challenging to measure over long time periods. We tested the utility of a novel method of using shrub growth rings to estimate stand-level biomass accumulation at an annual time scale in southern California chaparral. We examined how temporal variation in precipitation and spatial variation in solar irradiation influence that accumulation. Using field measurements and a relationship between stem basal area and aboveground biomass, we estimated current biomass levels in an 11-year-old chaparral stand, and used growth-ring diameters to estimate growth in each year from age 4 to 11 years. We found that annual growth as measured by shrub growth rings tracked closely with patterns of annual precipitation, but not with time since fire. Solar irradiation was not found to be a significant covariate with total biomass by plot, possibly due to sampling area limitations. The close relationship of annual biomass accumulation with annual precipitation indicates that shrub growth-ring measurements can provide a useful metric of stand-level recovery.

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.

Community composition and allometry of Leucothoe davisiae, Cornus sericea, and Chrysolepis sempervirens

2014 ◽  
Vol 44 (6) ◽  
pp. 677-683 ◽  
Author(s):  
James A. Lutz ◽  
Kaitlyn A. Schwindt ◽  
Tucker J. Furniss ◽  
James A. Freund ◽  
Mark E. Swanson ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Explanatory Power ◽  
Fire Behavior ◽  
Total Biomass ◽  
Fuel Loading ◽  
Basal Diameter ◽  
Cornus Sericea ◽  
Forest Dynamics Plot ◽  
Shrub Patches ◽  
Species Specific

Leucothoe davisiae Torr. ex A. Gray (Ericaceae), Sierra laurel, is an endemic shrub of the Sierra Nevada, Klamath Mountains, and Warner Mountains. We compared the woody plant community and allometry of Leucothoe with one widespread wetland shrub, red osier dogwood (Cornus sericea L. (Cornaceae)), and one widespread upland shrub, bush chinquapin (Chrysolepis sempervirens (Kellogg) Hjelmq. (Fagaceae)), in an Abies concolor – Pinus lambertiana forest. We examined 2282 mapped shrub patches and 34 392 trees in the Yosemite Forest Dynamics Plot (25.6 ha), Yosemite National Park, California, USA. We dissected 40–41 stems of each shrub species and determined foliage, bark, wood, and total biomass as a function of stem diameter. Community compositions determined from plants within a 5 m buffer of Leucothoe were different from those reported for Leucothoe communities in the Siskiyou National Forest and the Central Klamath. Leucothoe allometry based on basal diameter was more variable (total biomass R2 = 0.64; P < 0.001) than that of Cornus (R2 = 0.93; P < 0.001) or Chrysolepis (R2 = 0.95; P < 0.001), reflecting greater canopy variation. Allometry based on diameter at 1.37 m along the main stem offered equivalent explanatory power for Cornus (R2 = 0.89; P < 0.001) and Chrysolepis (R2 = 0.84; P < 0.001), but Leucothoe rarely reached that stature. These allometric equations that we report can improve species-specific modeling of carbon dynamics, fuel loading, and fire behavior.

Inter-decadal variation in clastic sediment yield from a forested mountain basin in relation to natural and anthropogenic disturbances

2020 ◽  
Author(s):  
Piotr Cienciala ◽  
Mishel Melendez Bernardo ◽  
Andrew Haas ◽  
Andrew Nelson
Keyword(s):  
Pacific Northwest ◽  
Sediment Yield ◽  
Timber Harvest ◽  
Anthropogenic Disturbances ◽  
Interactive Effects ◽  
Decadal Variation ◽  
Clastic Sediment ◽  
Denudation Rates ◽  
Sediment Routing ◽  
Order Of Magnitude

&lt;p&gt;The variability in fluvial yield of clastic sediment is a useful metric of the upstream basin's geomorphic response to natural and anthropogenic landscape disturbances. It reflects an integrated signal of sediment mobilization and connectivity, that is the efficiency with which the mobilized material is evacuated by the sediment routing system. Average clastic sediment yield has also been used as a measure of mechanical denudation rates, although material storage along the routing system necessitates caution in such inferences.&lt;/p&gt;&lt;p&gt;Insight into the geomorphic responses to disturbances, provided by sediment yield analysis, is crucial for the understanding and management of river ecosystems. In the context of ongoing environmental change, intermediate-term system responses (spanning decades-to-centuries) to shifting disturbance regimes are of particular interest. Because of non-stationary conditions and high variability in fluvial sediment transport, knowledge developed based on short-term records of instrumented measurements is not readily transferrable to such longer time-scales. As a result, there is a need for more research focused on multi-decadal sediment yield patterns.&amp;#160;&lt;/p&gt;&lt;p&gt;This research addresses such a research need, by estimating clastic sediment yield from a forested mountain basin in NE Washington (USA) during a period of 107 years. To this end, we use historical aerial imagery and track, at the decadal resolution, sedimentation associated with delta growth following the construction of a dam. We interpret these data in the context of available records of streamflow and timber harvest operations, which constitute primary natural and anthropogenic disturbances.&amp;#160;&lt;/p&gt;&lt;p&gt;Preliminary results suggest relatively low sediment yield from the study basin, almost an order of magnitude lower than those reported from the coastal Pacific Northwest. We interpret inter-decadal variation in sediment yield estimates as indicative of interactive effects of flow forcing and land cover disturbance magnitude. We also believe that, because of variations of connectivity within the routing system, the sensitivity of sediment yield to disturbance at this time-scale is modulated by the location within the basin relative to its outlet.&lt;/p&gt;

Predicting deposition of debris flows in mountain channels

1990 ◽  
Vol 27 (4) ◽  
pp. 409-417 ◽  
Author(s):  
Lee E. Benda ◽  
Terrance W. Cundy
Keyword(s):  
Pacific Northwest ◽  
Debris Flows ◽  
Field Measurements ◽  
Coast Range ◽  
Oregon Coast Range ◽  
Oregon Coast ◽  
Aerial Photos ◽  
The Pacific ◽  
Channel Slope ◽  
Junction Angle

An empirical model for predicting deposition of coarse-textured debris flows in confined mountain channels is developed based on field measurements of 14 debris flows in the Pacific Northwest, U.S.A. The model uses two criteria for deposition: channel slope (less than 3.5°) and tributary junction angle (greater than 70°). The model is tested by predicting travel distances of 15 debris flows in the Oregon Coast Range and six debris flows in the Washington Cascades, U.S.A. The model is further tested on 44 debris flows in two lithological types in the Oregon Coast Range using aerial photos and topographic maps; on these flows only the approximate travel distance is known. The model can be used by resource professionals to identify the potential for impacts from debris flows. Key words: debris flow, deposition, travel, erosion.

Effects of salvage logging and pile-and-burn on fuel loading, potential fire behaviour, fuel consumption and emissions

2013 ◽  
Vol 22 (6) ◽  
pp. 757 ◽  
Author(s):  
Morris C. Johnson ◽  
Jessica E. Halofsky ◽  
David L. Peterson
Keyword(s):  
Fuel Consumption ◽  
Field Measurements ◽  
Flame Length ◽  
Pollutant Emissions ◽  
Fire Behaviour ◽  
Treatment Combination ◽  
Fuel Loading ◽  
Fuel Treatment ◽  
Salvage Logging ◽  
Study Results

We used a combination of field measurements and simulation modelling to quantify the effects of salvage logging, and a combination of salvage logging and pile-and-burn fuel surface fuel treatment (treatment combination), on fuel loadings, fire behaviour, fuel consumption and pollutant emissions at three points in time: post-windstorm (before salvage logging), post-salvage logging and post-surface fuel treatment (pile-and-burn). Salvage logging and the treatment combination significantly reduced fuel loadings, fuelbed depth and smoke emissions. Salvage logging and the treatment combination reduced total surface fuel loading (sound plus rotten) by 73 and 77%. All fine woody fuels (<7.6cm) were significantly reduced by salvage logging and the treatment combination. In contrast, there was significant increase in the 1000-h (7.6–22.9cm) fuel loading. Salvage logging and the treatment combination reduced mean fuelbed depth by 38 and 65%. Salvage logging reduced PM2.5 emissions by 19%, and the treatment combination reduced emissions by 27%. Salvage logging and the treatment combination reduced PM10 emissions by 19 and 28%. We observed monotonic changes in flame length, reaction intensity and rate-of-spread after salvage logging and treatment combination. Study results illustrate potential differences between the effects of salvage logging after windstorms and the effects of salvage logging after wildfire.

Survey of Fragile Geologic Features and Their Quasi-Static Earthquake Ground-Motion Constraints, Southern Oregon

2021 ◽  
Author(s):  
Devin McPhillips ◽  
Katherine M. Scharer
Keyword(s):  
Ground Motion ◽  
Pacific Northwest ◽  
Field Measurements ◽  
Point Clouds ◽  
Earthquake Ground Motion ◽  
Ground Shaking ◽  
Motion Constraints ◽  
Megathrust Earthquakes ◽  
The Pacific ◽  
Rock Pillars

ABSTRACT Fragile geologic features (FGFs), which are extant on the landscape but vulnerable to earthquake ground shaking, may provide geological constraints on the intensity of prior shaking. These empirical constraints are particularly important in regions such as the Pacific Northwest that have not experienced a megathrust earthquake in written history. Here, we describe our field survey of FGFs in southern Oregon. We documented 58 features with fragile geometric characteristics, as determined from field measurements of size and strength, historical photographs, and light detection and ranging point clouds. Among the surveyed FGFs, sea stacks have particular advantages for use as ground-motion constraints: (1) they are frequently tall and thin; (2) they are widely distributed parallel to the coast, proximal to the trench and the likely megathrust rupture surface; and (3) they are formed by sea cliff retreat, meaning that their ages may be coarsely estimated as a function of distance from the coast. About 40% of the surveyed sea stacks appear to have survived multiple Cascadia megathrust earthquakes. Using a quasi-static analysis, we estimate the minimum horizontal ground accelerations that could fracture the rock pillars. We provide context for the quasi-static results by comparing them with predictions from kinematic simulations and ground-motion prediction equations. Among the sea stacks old enough to have survived multiple megathrust earthquakes (n = 16), eight yield breaking accelerations lower than the predictions, although they generally overlap within uncertainty. FGFs with the lowest breaking accelerations are distributed uniformly over 130 km of coastline. Results for inland features, such as speleothems, are in close agreement with the predictions. We conclude that FGFs show promise for investigating both past earthquake shaking and its spatial variability along the coasts of Oregon and Washington, where sea stacks are often prevalent. Future work can refine our understanding of FGF age and evolution.

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