scholarly journals Modeling interactions between fire and atmosphere in discrete element fuel beds

2005 ◽  
Vol 14 (1) ◽  
pp. 37 ◽  
Author(s):  
Rodman Linn ◽  
Judith Winterkamp ◽  
Jonah J. Colman ◽  
Carleton Edminster ◽  
John D. Bailey
Keyword(s):  
Ponderosa Pine ◽  
Fire Behavior ◽  
Canopy Structure ◽  
Treatment Strategies ◽  
Convective Heating ◽  
Initial Attempt ◽  
Fuel Density ◽  
Porous Element ◽  
Tree Data ◽  
Fuel Elements

In this text we describe an initial attempt to incorporate discrete porous element fuel beds into the coupled atmosphere–wildfire behavior model HIGRAD/FIRETEC. First we develop conceptual models for use in translating measured tree data (in this case a ponderosa pine forest) into discrete fuel elements. Then data collected at experimental sites near Flagstaff, Arizona are used to create a discontinuous canopy fuel representation in HIGRAD/FIRETEC. Four simulations are presented with different canopy and understory configurations as described in the text. The results are discussed in terms of the same two discrete locations within the canopy for each simulation. The canopy structure had significant effects on the balance between radiative and convective heating in driving the fire and indeed sometimes determined whether a specific tree burned or not. In our simulations the ground fuel density was the determining factor in the overall spread rate of the fire, even when the overstory was involved in the fire. This behavior is well known in the fire meteorology community. In the future, simulations of this type could help land managers to better understand the role of canopy and understory structure in determining fire behavior, and thus help them decide between the different thinning and fuel treatment strategies available to them.

scholarly journals The Survival of Pinus ponderosa Saplings Subjected to Increasing Levels of Fire Behavior and Impacts on Post-Fire Growth

Fire ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 23 ◽  
Author(s):  
Wade D. Steady ◽  
Raquel Partelli Feltrin ◽  
Daniel M. Johnson ◽  
Aaron M. Sparks ◽  
Crystal A. Kolden ◽  
...  
Keyword(s):  
Dose Response ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Fire Hazard ◽  
Fire Behavior ◽  
Forest Growth ◽  
Growth And Yield ◽  
Radiative Energy ◽  
Fire Growth ◽  
Growth Metrics

Improved predictions of tree species mortality and growth metrics following fires are important to assess fire impacts on forest succession, and ultimately forest growth and yield. Recent studies have shown that North American conifers exhibit a ‘toxicological dose-response’ relationship between fire behavior and the resultant mortality or recovery of the trees. Prior studies have not been conclusive due to potential pseudo-replication in the experimental design and time-limited observations. We explored whether dose-response relationships are observed in ponderosa pine (Pinus ponderosa) saplings exposed to surface fires of increasing fire behavior (as quantified by Fire Radiative Energy—FRE). We confirmed equivalent dose-response relationships to the prior studies that were focused on other conifer species. The post-fire growth in the saplings that survived the fires decreased with increasing FRE dosages, while the percentage mortality in the sapling dosage groups increased with the amount of FRE applied. Furthermore, as with lodgepole pine (Pinus contorta), a low FRE dosage could be applied that did not yield mortality in any of the replicates (r = 10). These results suggest that land management agencies could use planned burns to reduce fire hazard while still maintaining a crop of young saplings. Incorporation of these results into earth-system models and growth and yield models could help reduce uncertainties associated with the impacts of fire on timber growth, forest resilience, carbon dynamics, and ecosystem economics.

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.

scholarly journals Effects of Biomass Removal Treatments on Stand-Level Fire Characteristics in Major Forest Types of the Northern Rocky Mountains

2010 ◽  
Vol 25 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Elizabeth D. Reinhardt ◽  
Lisa Holsinger ◽  
Robert Keane
Keyword(s):  
Ponderosa Pine ◽  
Rocky Mountains ◽  
Fire Behavior ◽  
Fire Effects ◽  
Forest Types ◽  
Prescribed Burns ◽  
Northern Rocky Mountains ◽  
Biomass Removal ◽  
Fuel Dynamics ◽  
Fire Characteristics

Abstract Removal of dead and live biomass from forested stands affects subsequent fuel dynamics and fire potential. The amount of material left onsite after biomass removal operations can influence the intensity and severity of subsequent unplanned wildfires or prescribed burns. We developed a set of biomass removal treatment scenarios and simulated their effects on a number of stands that represent two major forests types of the northern Rocky Mountains: lodgepole and ponderosa pine. The Fire and Fuels Extension to the Forest Vegetation Simulator was used to simulate effects including stand development, fire behavior, and fire effects prior to the biomass removal treatment and 1, 10, 30, and 60 years after the treatment. Analysis of variance was used to determine whether these changes in fuel dynamics and fire potential differed significantly from each other. Results indicated that fire and fuel characteristics varied within and between forest types and depended on the nature of the treatment, as well as time since treatment. Biomass removal decreased fire potential in the short term, but results were mixed over the long term.

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.

Fuel treatment effects on modeled landscape-level fire behavior in the northern Sierra Nevada

2010 ◽  
Vol 40 (9) ◽  
pp. 1751-1765 ◽  
Author(s):  
Jason J. Moghaddas ◽  
Brandon M. Collins ◽  
Kurt Menning ◽  
Emily E.Y. Moghaddas ◽  
Scott L. Stephens
Keyword(s):  
Sierra Nevada ◽  
Fire Behavior ◽  
Treatment Strategies ◽  
Weather Conditions ◽  
Fire Regimes ◽  
Flame Length ◽  
Fuel Treatment ◽  
Burn Probability ◽  
Pre Treatment ◽  
Landscape Level

Across the western United States, decades of fire exclusion combined with past management history have contributed to the current condition of extensive areas of high-density, shade-tolerant coniferous stands that are increasingly prone to high-severity fires. Here, we report the modeled effects of constructed defensible fuel profile zones and group selection treatments on crown fire potential, flame length, and conditional burn probabilities across 11 land allocation types for an 18 600 ha study area within the northern Sierra Nevada, California. Fire modeling was completed using FlamMap and FARSITE based on landscape files developed with high-resolution aerial (IKONOS) imagery, ground-based plot data, and integrated data from ARCFUELS and the Forest Vegetation Simulator. Under modeled 97th percentile weather conditions, average conditional burn probability was reduced between pre- and post-treatment landscapes. A more detailed simulation of a hypothetical fire burning under fairly severe fire weather, or “problem fire”, revealed a 39% reduction in final fire size for the treated landscape relative to the pre-treatment condition. To modify fire behavior at a landscape level, a combination of fuel treatment strategies that address topographic location, land use allocations, vegetation types, and fire regimes is needed.

A comparison of the growth basal area stocking level curve to a number of curves developed from south central Oregon tree data

1986 ◽  
Vol 16 (3) ◽  
pp. 508-512
Author(s):  
William E. Hopkins
Keyword(s):  
Ponderosa Pine ◽  
Basal Area ◽  
Climatic Conditions ◽  
Diameter Growth ◽  
The West ◽  
South Central ◽  
White Fir ◽  
Significant Difference ◽  
Tree Data ◽  
Single Regression

A single regression supporting the growth basal area concept was compared with regressions developed from various south central Oregon coniferous trees. Growth basal area is the basal area at which dominant trees grow 1 in. (25 mm) in diameter per decade referenced at age 100 years. Regressions developed from ponderosa pine (Pinusponderosa Laws.) and lodgepole pine (Pinuscontorta Dougl.) data were significantly different from the single published regression. White fir (Abiesconcolor Gord. & Glend.) and Shasta red fir (Abiesmagnifica var. shastensis Lemm.) data also proved to be significantly different. Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) data indicated no significant difference when compared with the published growth basal area curve. Therefore, application of the published growth basal area curve to stands found in south central Oregon would be considerably less precise than those curves developed from tree data collected in south central Oregon. Since tree stockability and diameter growth react to both edaphic and climatic conditions, caution is extended to users in other parts of the west.

scholarly journals Mastication and Prescribed Fire Influences on Tree Mortality and Predicted Fire Behavior in Ponderosa Pine

2012 ◽  
Vol 27 (1) ◽  
pp. 36-41 ◽  
Author(s):  
Alicia L. Reiner ◽  
Nicole M. Vaillant ◽  
Scott N. Dailey
Keyword(s):  
Pinus Ponderosa ◽  
Prescribed Fire ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Block Design ◽  
Fire Behavior ◽  
Mortality Data ◽  
Before And After ◽  
Random Block Design ◽  
Four Blocks

Abstract The purpose of this study was to provide land managers with information on potential wildfire behavior and tree mortality associated with mastication and masticated/fire treatments in a plantation. Additionally, the effect of pulling fuels away from tree boles before applying fire treatment was studied in relation to tree mortality. Fuel characteristics and tree mortality data were gathered before and after treatments in a 25-year-old ponderosa pine (Pinus ponderosa C. Lawson) plantation. A random block design was used with three treatments plus a control at each of four blocks. Four plots were established as subsamples within each of the treatment and control sections of each block. Potential wildfire behavior for posttreatment fuel conditions was modeled for 90th and 97th percentile fire weather. Predicted rates of spread and flame lengths were higher for fuel conditions resulting from the mastication treatments than for the masticated/fire treatments or the controls. Torching and crowning indices indicated that higher windspeeds would be necessary to promote torching for areas treated with mastication/fire than for mastication or the controls. Tree mortality was 32 and 17% the first year after burning in masticated/fire and masticated/pull-back/fire plots, respectively, and 49 and 27% the second year. Our potential wildfire behavior results indicate that the risk of crown fire can be somewhat reduced by mastication and further reduced if mastication is followed up with prescribed fire to consume surface fuels. However, moderate levels of tree mortality seem inevitable when burning masticated fuels in a plantation and may only marginally be reduced by pulling fuels away from tree boles, which increases treatment costs.

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