Fire Behavior and Fire Effects on Eastern Redcedar in Hardwood Leaf-Litter Fires

1995 ◽  
Vol 5 (3) ◽  
pp. 135 ◽  
Author(s):  
DM Engle ◽  
JF Stritzke
Keyword(s):  
Leaf Litter ◽  
Fire Behavior ◽  
Late Summer ◽  
Ambient Air ◽  
Fire Effects ◽  
Cross Timbers ◽  
Fuel Loading ◽  
Eastern Redcedar ◽  
Crown Scorch ◽  
In Fire

Treatment of stands of hardwoods in the cross timbers of the central United States with tebuthiuron (N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-dimethylurea) can significantly decrease canopy cover of hardwoods. However, at the rate used for hardwood control, tebuthiuron does not control eastern redcedar (Juniperus virginiana L.). Our objective was to determine the potential of using fires in the hardwood leaf litter, either before or after tebuthiuron, for controlling eastern redcedar. To do this, we compared fuelbed characteristics, fire behavior, and fire effects on eastern redcedar in naturally occurring hardwood leaf litter with those augmented by leaves dropped following a single application of tebuthiuron. Studies were conducted in 1988, 1989, and 1991 on a cross timbers site dominated by an overstory of post oak (Quercus stellata Wangenh.) and blackjack oak (Q. marilandica Muenchh.) and with eastern redcedar in the understory. Factors evaluated included herbicide treatment (tebuthiuron or no herbicide) and burning season (late summer or winter). Tebuthiuron at 2.2 kg a.i. Ha-1 was applied to plots (25 X 25 m) in March of the study years. In late summer, tebuthiuron-treated plots contained almost twice the 1-hr fuel loading as untreated plots. Fuel depth on untreated plots in late summer was about half that of other herbicide treatments and burning date combinations. Fuel loading on plots burned in winter was not affected by tebuthiuron treatment, and no differences in fuel consumption were detected among any treatments. Moisture content of 1-hr fuels on plots burned in winter was more than twice that of 1-hr fuels on plots burned in late summer. Fire intensity was low with all bums, and no differences in fire behavior were detected among any treatments. Crown scorch of 75% or greater on small eastern redcedar trees was considered a successful burn, and this resulted on all but the late summer-no tebuthiuron treatment. The natural log of fireline intensity explained about 47% (P<0.0006)) of the variation in fire success, and ambient air temperature explained an additional 19% (P<0.0468). Although tebuthiuron treatments effectively augmented leaf-litter fuel load by late-summer and provided a suitable fuelbed for burning, crown scorch and tree kill were not greatly improved by burning in late summer as compared to winter. We conclude that understory eastern redcedar can be controlled successfully by burning leaf-litter fuelbeds in either late fall or winter after natural leaf-fall from hardwood trees or in late summer, fall, or winter following a spring application of tebuthiuron for control of overstory hardwoods.

Fire effects on the spatial patterns of soil resources in a Nicaraguan wet tropical forest

2005 ◽  
Vol 21 (4) ◽  
pp. 435-444 ◽  
Author(s):  
Brent C. Blair
Keyword(s):  
Leaf Litter ◽  
Tropical Forests ◽  
Forest Fires ◽  
Soil Heterogeneity ◽  
Fire Effects ◽  
Fire Intensity ◽  
Vegetative Cover ◽  
Soil Resources ◽  
In Fire ◽  
The Impact

Anthropogenic wildfires are becoming increasingly frequent in wet tropical forests. This trend follows that of other anthropogenic disturbances, which are now acute and widespread. Fires pose a potentially serious threat to tropical forests. However, little is known about the impact of unintended forest fires on below-ground resources in these ecosystems. This study investigated the influence of fires on the distribution and variability of soil resources on two sets of 50×50-m burned and unburned plots in a Nicaraguan rain forest. Samples were collected at 5-m intervals throughout each plot as well as subsamples at 50-cm intervals. Geostatistical techniques as well as univariate statistics were used to quantify the spatial autocorrelation and variability of selected nutrients (N, P and K), carbon and standing leaf litter. Most variability in this forest was spatially dependent at a scale of 30 m or less. However the average range of autocorrelations varied greatly between properties and sites. Burning altered soil heterogeneity by decreasing the range over which soil properties were autocorrelated. Overall the average patch size (range) for nitrogen was reduced by 7%, phosphorus by 52%, potassium by 60% and carbon by 43%. While phosphorus and leaf litter increased in the burned plots compared to unburned plots, potassium was not different. Nitrogen and carbon did not display a consistent pattern between burning regimes and this may be explained by variation in fire intensity. Leaf litter measurements did not correlate with measured soil nutrients within plots. Observed changes in the burned forest were likely a result of both the intensity of burning and change in vegetative cover between the time of the fires and soil sampling.

Using catastrophe theory to model wildfire behavior and control

1998 ◽  
Vol 28 (6) ◽  
pp. 852-862 ◽  
Author(s):  
Hayley Hesseln ◽  
Douglas B Rideout ◽  
Philip N Omi
Keyword(s):  
Cost Minimization ◽  
Fire Behavior ◽  
Fuel Moisture ◽  
Costs And Benefits ◽  
Fuel Loading ◽  
Marginal Costs ◽  
Management Objectives ◽  
Initial Fuel ◽  
In Fire ◽  
And Control

Forest wildfire managers are obligated to meetecosystem management objectives, such as cost minimization andresource allocation efficiency (J.T. Williams, R.G. Schmidt,R.A., Norum, P.N. Omi, and R.G. Lee. 1993. USDA For. Serv.Staffing Pap. Washington, D.C.), which is difficult because eachobjective is dependent upon wildfire controllability andbehavior. Currently, there is no functional formula that definesthe relationship between wildfire behavior and controllabilityand therefore, no physical basis for efficient economic analysis.This paper seeks to (1) identify environmental factors thatsystematically predict wildfire controllability and the rangeover which sudden changes in fire behavior occur, (2) quantifythe uncertainty of fire behavior in terms of the environmentalfactors, and (3) define a manageable environmental variablethat can be used to determine marginal costs and benefits ofwildfire management activities. We develop the theory and providean illustrative example of a cusp catastrophe using simulatedfire data. Preliminary results suggest that catastrophe theorymay be an effective tool to model wildfire controllability asmeasured by the modeled change in fireline intensity, windspeed,initial fuel moisture and fuel loading. Because the use of fuelloading as a control parameter describes the marginal physicaleffects on wildfire behavior, this framework may prove suitableas the production relationship for future economic analysis. Notethat the model specified in this paper is theoretical and shouldnot be applied until validated.

Microplot Sampling of Fire Behavior on Populus tremuloides Stands in North-Central Colorado

1993 ◽  
Vol 3 (2) ◽  
pp. 85 ◽  
Author(s):  
JK Smith ◽  
RD Laven ◽  
PN Omi
Keyword(s):  
Populus Tremuloides ◽  
Fire Behavior ◽  
Fire Effects ◽  
Flame Length ◽  
Fire Intensity ◽  
Total Heat Release ◽  
Spread Rate ◽  
North Central ◽  
Area Burned ◽  
In Fire

Fire behavior research has traditionally used whole burns as sampling units. Numerous burns were required to quantify relationships between pre-burn descriptors, fire behavior, and fire effects. Recent studies have used small plots within burns (called microplots) as the sampling units. This study measured pre-burn descriptors and fire behavior on 0.75-m2 microplots in two Populus tremuloides Michx. burns in north-central Colorado. Microplot estimates of woody fuels, spread rate, and area burned were comparable with measurements from whole burns. Two methods of estimating fire intensity on microplots produced inconsistent results. Juniperus communis L. patches burned more intensely and released more heat than herbaceous areas. Duff characteristics were the most useful pre-burn descriptors for predicting area burned, spread rate, flame length, and total heat release. Microplot sampling on two bums enabled us to relate variability in fire behavior to pre-burn characteristics and to obtain replicate estimates of these relationships.

scholarly journals Chronosequence of Fuel Loading and Fuel Depth Following Forest Rehabilitation Frill Treatment of Tanoak to Release Douglas-Fir: A Case Study from Northern California

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 691
Author(s):  
Raven M. Krieger ◽  
Brian E. Wall ◽  
Cody W. Kidd ◽  
John-Pascal Berrill
Keyword(s):  
Woody Debris ◽  
Fire Severity ◽  
Fire Behavior ◽  
Fire Effects ◽  
Behavior Modeling ◽  
Northern California ◽  
Fuel Loading ◽  
Excessive Competition ◽  
Pre Treatment ◽  
Forest Rehabilitation

There is concern that forest management activities such as chemical thinning may increase hazardous fuel loading and therefore increase risk of stand-replacing wildfire. Chemical thinning, often accomplished by frill treatment of unwanted trees, leaves trees standing dead for a time before they fall and become surface fuels. In coastal northern California, frill treatment is used as a forest rehabilitation treatment that removes tanoak (Notholithocarpus densiflorus) to release merchantable conifers from excessive competition. We studied fuel bed depth and fuel loading after frill treatment of tanoak along a 16-year chronosequence that substituted space for time. The total depth of fuel bed was separated into woody fuels, litter, and duff. The height of each layer was variable and greatest on average in post-treatment year 5 after treated tanoak had begun to break apart and fall. Initially, the evergreen tanoak trees retained their foliage for at least a year after treatment. Five years after treatment, many tanoak had fallen and transitioned to become fine- and coarse woody debris. After 11 years, the larger pieces of down wood were mostly classified as rotten. After 16 years, the fuel loading appeared roughly equivalent to pre-treatment levels, however we did not explicitly test for differences due to potential confounding between time and multiple factors such as inter-annual climate variations and site attributes. Nevertheless, our data provide some insight into changes in surface fuel characteristics due to rehabilitation treatments. These data can be used as inputs for fire behavior modeling to generate indicative predictions of fire effects such as fire severity and how these change over time since treatment.

scholarly journals Slash Compression Treatment Reduced Tree Mortality from Prescribed Fire in Southwestern Ponderosa Pine

2004 ◽  
Vol 19 (3) ◽  
pp. 149-153 ◽  
Author(s):  
Peter Z. Fulé ◽  
Jason L. Jerman ◽  
Peter J. Gould
Keyword(s):  
Forest Structure ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Prescribed Burning ◽  
Fire Effects ◽  
Fuel Loading ◽  
Old Growth ◽  
Crown Scorch ◽  
Tree Survival ◽  
Compression Treatment

Abstract Intensive thinning prescriptions intended to restore historic forest structure have produced heavy broadcast slash fuel loads in northwestern Arizona, sometimes leading to high tree mortality following prescribed burning. Mechanical slash compression with a D-6 bulldozer to reduce the severity of fire effects on residual trees was evaluated. Ten of 42 measured trees (24%) died within 2 years after burning of broadcast slash, and crown scorch of trees without slash compression treatment averaged 26%. In contrast, no trees died after burning of compressed slash and crown scorch averaged <3%, even though the total fuel loading was indistinguishable from the broadcast slash treatment. The practice of raking fuels away from the boles of old-growth trees also contributed to reduced scorch as compared to younger, unraked trees. Slash compression is a viable method of reducing mortality, offering ecological and economical tradeoffs. Benefits include the ability to reduce large quantities of slash, safeguarding old-growth tree survival while rapidly achieving open forest structure. Costs include paying for equipment operation as well as the possibility of damage to soils or plants. West. J. Appl. For. 19(3):149–153.

scholarly journals Post-fire consequences for leaf breakdown in a tropical stream

2019 ◽  
Vol 31 ◽  
Author(s):  
Renan de Souza Rezende ◽  
Cristiano Queiroz de Albuquerque ◽  
Andrezza Sayuri Victoriano Hirota ◽  
Paulo Fernandes Roges Souza Silva ◽  
Ricardo Keichi Umetsu ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Fungal Biomass ◽  
Mesh Size ◽  
Fire Effects ◽  
Dry Mass ◽  
Tropical Stream ◽  
Fire Event ◽  
Litter Bags ◽  
Fine Mesh ◽  
Post Fire Effects

Abstract Aim Wildfire is a natural pulsed disturbance in landscapes of the Savannah Biome. This study evaluates short-term post-fire effects on leaf litter breakdown, the invertebrate community and fungal biomass of litter from three different vegetal species in a tropical stream. Methods Senescent leaves of Inga laurina, Protium spruceanum and Rircheria grandis (2 ± 0.1 g dry mass) were individually placed in litter bags (30 × 30 cm: 10 mm coarse mesh and 0.5 mm fine mesh) and submerged in the study stream before and after fire. Replicate bags (n = 4; individually for each species, sampling time, fire event and mesh size) were then retrieved after 20 and 40 days and washed to separate the invertebrates before fire event and again immediately after fire. Disks were cut from leaves to determine ash-free dry mass, while the remaining material was oven-dried to determine dry mass. Results The pre-fire mean decomposition coefficient (k = -0.012 day-1) was intermediate compared to that reported for other savannah streams, but post-fire it was lower (k = -0.007 day-1), due to decreased allochthonous litter input and increased autochthones production. Intermediate k values for all qualities of litter post-fire may indicate that fire is equalizing litter quality in the stream ecosystem. The abundance of scrapers was found to be more important than fungal biomass or shredder abundance, probably due to their functioning in leaf fragmentation while consuming periphyton growing on leaf litter. Conclusions Theses results indicate that fire can modify the relationships within decomposer communities in tropical stream ecosystems.

Flashover and instabilities in fire behavior

1980 ◽  
Vol 38 ◽  
pp. 159-171 ◽  
Author(s):  
P.H. Thomas ◽  
M.L. Bullen ◽  
J.G. Quintiere ◽  
B.J. McCaffrey
Keyword(s):  
Fire Behavior ◽  
In Fire

Changes in fire behavior caused by fire exclusion and fuel build-up vary with topography in California montane forests, USA

2022 ◽  
Vol 304 ◽  
pp. 114255
Author(s):  
Catherine Airey-Lauvaux ◽  
Andrew D. Pierce ◽  
Carl N. Skinner ◽  
Alan H. Taylor
Keyword(s):  
Fire Behavior ◽  
Montane Forests ◽  
Fire Exclusion ◽  
In Fire

Numerical Analysis of Fire Behavior of a Large Space Pre-Stressed Steel Structure under Fire

2011 ◽  
Vol 71-78 ◽  
pp. 3729-3732
Author(s):  
Ming Zhou ◽  
Zhi Guo Xie ◽  
Xin Tang Wang
Keyword(s):  
Numerical Analysis ◽  
Fire Behavior ◽  
Thermal Response ◽  
Structural Response ◽  
Steel Structure ◽  
Large Space ◽  
Fire Source ◽  
Lattice Shell ◽  
In Fire ◽  
Influence Degree

The computational model of numerical analysis of a suspended pre-stressed steel reticulated shell subjected to fire load is established with using the software Marc. Based on the model presented here, numerical analysis of thermal response and structural response of the pre-stressed steel structure are computed. The different space height and different rise-span ratio are considered for analysis of response temperature, displacements and stresses of the pre-stressed lattice shell under fire for one fire source. It is also shown that displacement of the node right above the inner cable is the maximum among the four nodes presented here as the fire source is located at the position right below the second-ring cable of the structure. It is concluded that the influence degree of space height of the structure on the fire response of the structure is not great, but rise-span ratio has obvious and great effect on displacements and stresses of the pre-stressed steel structure with large span in fire.

Sign in / Sign up

Export Citation Format

Share Document