bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Cutting and Burning on Browse Production in Eastern Canadian Aspen Forests
Authors: Weber MG
Published: October 2005

A 20-year-old aspen (Populur tremloides Michx.) ecosystem was subjected to two cutting and two burning treatments. Cutting and prescribed burning were carried out on separate areas . One cutting and one burning treatment was aplied both before and after spring leaf flush. An untreated control area was set aside for comparison.
Three years after treatment summer and winter aspen browse production for moose (Alcesaices) and white-tailed deer (Odocoileus virginianus) were greatest on the preflush cutting treatment (summer — 1544 kg.ha-1; winter — 395 kgha-1) followed in decreasing order by post-flush cut (summer — 635 kg.ha-1; winter — 125 kg.ha-1), postflush burn (summer — 330 kg.ha-1; winter — 96 kg.ha-1), and pre-flush burn (summer — 50 kg.ha-1; winter — no browsing). Aspen browse quality (nutrient concentration) was essentially unaffected by treatment. Post treatment
biomass production of aspen is discussed in terms of known physiological and ecological responses to disturbance.
Influence of Sample Processing Techniques and Seasonal Variation on Quantities of Volatile Compounds of Gallberry, Saw-Palmetto, and Wax Myrtle
Authors: Burgan RE , Susott RA
Published: October 2005

Combustible gas analysis was used to study seasonal changes in the quantity of volatiles in foliage of gallberry (Ilex glabra), wax myrtle (Myrica cerifera) and saw palmetto (Serenoa repens). Small). Fresh and freeze-dried samples were compared to determine whether freeze-drying and grinding reduces the quantity of low-temperature volatiles prior to pro-
cessing. Seasonal differences in volatile content do seem
to occur, particularly in gallberry. Freeze-drying and
grinding samples prior to processing did not seem to
affect volatile retention.
Southern Oscillation Anomalies and Their Relationship to Wildfire Activity in Florida
Authors: Brenner J
Published: October 2005

Some relationships between the EI Nino / Southern Oscillation (ENSO) and wildfire in Florida are examined. Unlike many ENSO / wildfire studies to date, no particular emphasis was placed on the positive side of the ENSO. Both the positive and negative sides were equally examined. Linear correlation coefficients, scatter diagrams and line graphs are constructed to compare acres burned with indices of central and eastern Pacific sea surface temperature and pressure anomalies. The study reveals a significant relationship between anomalous
sea surface temperatures and sea level pressures in the tend and eastern Pacific, and acres burned in Florida due to wildfires. The typical fire season in Florida is during the winter months, and the best correlation coefficient ("r" 0.71) was derived from the average central Pacific sea surface temperature anomaly for the period January through my, indicating it correlated with
up to 50% of the variance in acres burned during the years examined. The study further suggests that it may be possible to develop a predictive model for wildfii activity in Florida, based on observed anomalies of sea surface temperatwe and sea level pressure in the central and
eastern Pacific.
On the Temperature Distribution Inside a Tree Under Fire Conditions
Authors: Costa JJ , Oliveira LA , Viegas DX , Neto LP
Published: October 2005

A simple and efficient numerical scheme is presented for the prediction of temperature field distribution inside a tree trunk subjected to ground fire conditions. The trunk is modelled by a cylinder of circular cross section and unit length, through which the time-dependent heat conduction equation is numerically integrated. The model is partly validated in laboratory and then applied to the case of a prescribed ground fire inside a Pinus pinmter stand.
Analysis of Experimental Simulation of Ground Surface Heating During a Prescribed Burn
Authors: Pafford D , Dhir VK , Anderson E , Cohen J
Published: October 2005

Ground surface heating during a prescribed bum is modeled. Primarily, the ground surface heating occurs by radiant exchange with the flames. Additional surface heating occurs when hot ash is deposited upon the ground. Heat losses from the ground surface occur by radiant transfer to the sky and surroundings, by conductive transfer of energy into the ground, and by convective
transfer to the ambient air. Important flame input characteristics used in the model are: the flame residence time, flame geometry, and flame temperature. Important ash parameters are: inif al ash temperature, location of initial contact of ash with the ground surface, and the thickness
of the ash layer. The analysis indicates that in the absence of an ash layer the location of the highest surface temperature is dependent only upon the flame geometry pararneters. However, the magnitude of the ground surface temperature is dependent upon flame geometry, the radiant
properties of the flame, and the thermophysical properties of the ground. Results from the model are compared with experimental data. The data were obtained by igniting a prepared fuel bed of chamise and manzanita branches loaded over a table top in which sand filled canisters, instrumented with thermocouples, were set flush with the table surface. The temperature distributions within the sand are found to compare well with the model predictions. Exceptions to the model are found to occur in burns featuring extensive smoldering ember beds.
Medium-range fire weather forecasts
Authors: Roads JO , Ueyoshi K , Chen SC , Alpert J , Fujioka F
Published: October 2005

The forecast skill of theNational Meteorological Center's medium range forecast (MRF) numerical
forecasts of fire weather variables is assessed for the period June 1,1988 to May 31,1990. Near-surface virtual temperature, relative humidity, wind speed and a derived fire weather index (FWI) are forecast well by the MRF model. However, forecast relative humidity has a wet bias during the winter and a slight dry bias during the summer, which has noticeable impact on forecasts of the derived fire weather index. The FWI forecasts are also strongly affected by near-surface wind forecast errors. Still, skillful forecasts of the fire weather index as well as the other relevant fire weather variables are made out to about 10 days. These forecasts could be utilized more
extensively by fire weather forecasters.
Behaviour of a Very Fast Grassland Wildfire on the Riverine Plain of Southeastern Australia.
Authors: Noble JC
Published: October 2005

A grassland wildfire burnt 120,000 ha in the
western Riverina of New South Wales and caused exten
sive losses of sheep and fencing. The rate of spread of the
fire was accurately recorded at 6.4 m s-1 (23 km h-1) as it
traversed one property and on the basis of conservative
estimates of fuel loads measured later on unburnt patches,
a fireline intensity was calculated at around 20,000 kW m-1.
This rate of spread is one of the highest recorded for
grassland wildfires in southern Australia and represents
an important datum point for wildfire behaviour models.
Quite reasonable predictions of rate of spread were pro
vided by the McArthur Mark 4 fire danger model, how
ever, the Mark 5 model seriously underestimated rate of
spread for this and two other grassland wildfires.
Regeneration in Quercus Pyrenaica Ecosystems After Surface Fires
Authors: Calvo L , Tarrega R , Luis E
Published: October 2005

Early post-fire structural dynamics in three
Quercus pyrenaica communities after intense fires was
studied. In the first year there is a marked domination of
perennial species (herbaceous or woody); afterwards,
herbaceous species tend to decrease in importance and
ligneous species increase. Changes in species diversity
were analysed as an indicator of recovery and stability in
the communities. An increase was observed in the second
year, and then diversity was maintained or reduced slightly
in the third and fourth years. Spatial heterogeneity tends
to diminish with time.
Estimating Fuel Moisture Response Times From Field Observations
Authors: Viney NR , Catchpole EA
Published: October 2005

The response time of a fuel element is defined
in terms of the response to a step change in moisture
content, and is not measurable in the field. However the
formulation of fine fuel moisture content as a continuous
process leads to a simple relationship between the re-
sponse time of the fuel and the time lag with respect to a
diurnally varying equilibrium moisture content. This
time lag is estimable from field data. This method is
applied to obtain response times for fine litter in a EucaIyptus forest. The same formulation is applied to the
discrete moisture content model of Fosberg and Deeming
(1971) which is re-cast and solved as a continuous model.
A Review of Fine Fuel Moisture Modelling
Authors: Viney NR
Published: October 2005

Models describing the moisture content of
forest fuels are an integral component of most fire
behaviour prediction systems. In this paper, models of all
aspects of moisture change in fine, dead, surface litter are
examined and reviewed. Included are models describing
the changes in moisture content associated with isother
mal vapour exchange by sorption processes, and the
effects of precipitation and condensation of liquid water.
Models for predicting fuel temperature and humidity, and
equilibrium moisture content are also assessed. Critical
reviews of the assumptions underlying each model are
made, and points of comparison and contrast explored.
Some recommendations for future research are suggested.
Nitrogen Losses to the Atmosphere From Grassland Fires in Saskatchewan, Canada
Authors: Redmann RE
Published: October 2005

Experimental spring fires burned 72-84% of the biomass in Saskatchewan grasslands dominated by either Festuca altaica ssp. hallii (Plains rough fescue) or Stipa spartea (Western porcupine grass) and Agropyron dasystachyum (Northern wheatgrass). Festuca stands had more fuel, and a higher combustion efficiency than
Stipa-Agropyron sites. Burning decreased total nitrogen by 3.7-6.7 g m-2 in Festuca grassland; nitrogen content of Stipa-Agropyron stands was not decreased significantly by burning. Indirect evidence (black ash color) suggested that fire temperatures were lower in Stipa-Agropyron stands. Controlled combustion experiments in the laboratory showed that 40-60% of tissue nitrogen was lost from Festuca shoots exposed to 300-400�C for three minutes. Losses of nitrogen from Festuca grassland are
approximately equal to or greater than published values for annual inputs and outputs of nitrogen in grassland ecosystems, depending on fire frequency.
Sampling Intensity for Estimating Fuel Moisture Content in Lodgepole Pine and White Spruce Trees
Authors: Titus SJ , Woodard PM , Johnson AF
Published: October 2005

The moisture content of live and dead foliage and roundwood on 30 lodgepole pine and 27 white spruce trees was determinedduring the summer of 1987. Sample trees were selectedrandomly throughout Alberta, Canada, without regard for weather. Five sub-samples were taken for each of the five roundwood diameter size classes (< 0.5cm,0.5 - 1 cm, 1.0- .0cm,3.0- 5.0cm, 5.0-7.0cm and 7.0-10.0 cm). Moisture content of live biomass was quite similar between species for the same fuel size class, regardless of when sampling occurred. Moisture content variation within trees was about half of the variation between trees for the same fuel size class. The coefficient of variation in moisture was much less for live material (generally < 0.3) than for dead biomass (always > 0.6). Average fuel moisture content for populations of lodgepole pine and white spruce trees may be estimated to within + 10% at the 68% probability level by sampling less than 20 trees and with only 3 fuel sub-samples per tree.
Temporal and Spatial Distribution of Savanna Fires in Senegal and the Gambia, West Africa, 1989-90, Derived From Multi-Temporal AVHRR Night Images
Authors: Langaas S
Published: October 2005

Quantitative data on fire regimes from the world's savannas have previously been difficult to obtain due to logistical and scientific reasons. This study addresses the issue for Senegal and The Gambia, West Africa. A bispectral satellite image based method for fire detection has recently been improved and made semi-automatic to provide information on fire regimes of savannas. The method uses thermal night time data from the Advanced Very High Resolution Radiometer (AVHRR) onboard the National Oceanic and Atrnospheric Administration (NOAA) series of weather satellites. Twenty-six near cloud-free AVHRR images have been classified using this method. Though they constitute a small temporal sample, some features of the seasonal periodicity and spatial variations of the region are suggested. Variations in firectivity at the four daily NOAA satellite passing times were recorded from a small field survey in The Gambia, and compared to data from the satellite images. Established relationships between reiative fire activity and data from the various NOAA passes have been used to estimate the maximum daily fire activity at the afternoon passing time. The seasonal variations for the whole study area and regions within are suggested by the estimated maximum values at the twenty-two dates. The locations of fire events in relation to locations of human activities and fuel loadings are examined and a brief summary of the main factors that regulate burning and fire regimes is given.
A Note on Fuelbeds and Fire Behavior in Alang-Alang (Imperata Cylindrica)
Authors: Pickford S , Suharti M , Wibowo A
Published: October 2005

Fire behavior on a 2 ha fire, inferred from
physical evidence observed one week after the fire, was
compared with fire behavior estimates obtained using the
BEHAVE fire behavior prediction system and fuel measurements in Imperata cylindrica (Alang-alang) made in
the same area. This fire probably burned under light
winds (3-5 km), high relative humidity, and spread slowly
with moderate flame lengths (approximately 100 m hr-1
spread rate, 0.5 - 0.7 m flame lengths). Although appar-
ently killed by lethal crown and bole scorch, the young
Acacia mangium overstory through which the fire burned
resprouted vigorously and apparently survived.
FIREMAP - Simulation of Fire Growth With a Geographic Information System
Authors: Vasconcelos MJ , Guertin DP
Published: October 2005

FIREMAP is a simulation system designed to
estimate wildfire characteristics in spatially non-uniform
environments and simulate the growth of fire in discrete
time steps. This simulation system integrates Rothermel's
behavior prediction model (Rothermel 1972) with a raster- based geographic information system. The outputs
can be displayed as digital maps. This paper describes the
concepts behind FIREMAP and compares simulation
results with a real fire occurrence. The predicted burned
area (138 ha) and the real burned area (132 ha) have a
similar overall shape.
Calibration and Field Testing of Passive Flame Height Sensors
Authors: Finney MA , Martin RE
Published: October 2005

The concept of a passive flame height sensor
involves thin strings permeated with fire retardant or
solder which record heights of flame contact. Both types
of sensors were calibrated during 12 experimental test
fires with respect to flame heights measured on video
tape. Three thresholds of fire damage to string-type
sensors were identified: singeing of fine string fibers,
complete blackening of the string, and thorough charring
or consumption. These damage thresholds were found to
exceed95%, 71% and48% of all flame heights measured
from video tape, respectively. 18-gauge solder melted to
a height exceeding 86% of measured flame heights. Field
testing of 512 sensors during prescribed burning affirmed
the potential practicality of this technique for estimating
flame length.
Prediction of Areas Prone to Lightning Ignition
Authors: McRae RHD
Published: October 2005

A method for handling lightning-caused
ignitions as part of a comprehensive fire hazard assessment
procedure is presented. The locations at which lightning
ignitions tend to occur have always been difficult to
predict, and do not correlate with usual environmental
factors. The model described here uses geographic
information system techniques to remove large-scale
trends in elevation. The meso-scale residual can be used
to predict sites that are prone to lightning ignitions. The
model is compared to historic records of lightning ignitions
for the ACT, and is found to work very well. A range of
other uses for the technique in fire management are
discussed.
Quadrat Analysis of Wildland Fuel Spatial Variability
Authors: Kalabokidis KD , Omi PN
Published: October 2005

Quadrat analysis of two fuel properties (loading and depth) was used to assess the relation between variation and sample plot size. By this method, an optimum range of spatial resolutions was established for sampling Artemisia tridentata subsp. wyomingensis (Wyoming big sagebrush) and Pinus contorta (lodgepole pine) fuel types in Colorado. Results of the analysis demonstrated that quadrats provide homogeneous strata and precise measures of central tendency on both fuelbeds studied. Findings indicated that field inventories in which A. tridentata is viewed as a fire fuel could use sample spacings up to 60 m (i.e., reasonably small sample sizes). The optimum range of resolution for the P. contorta fuel type was down to 20-30 m so that larger sample sizes are required. Quadrat analysis shed light on more precise fuel sampling schemes by accounting for the microsite variation of fuel characteristics. Thus, analogous studies can reveal further the semi-stochastic phenomena that govern wildland fire behaviour and effects.
Spatial Autocorrelation Analysis and Weighting Functions in the Distribution of Wildland Fires
Authors: Chou YH
Published: October 2005

Spatial autocorrelation and spatial weighting
functions are examined in relation to the distribution of
wildland fires. Records of fire activity and vegetation for
the Idyllwild 15-minute quadrangle of the San Jacinto
Mountains, San Bernardino National Forest, California,
are processed in a geographic information system to
generate six spatial weighting functions: contiguity, area,
boundary length, distance, area-distance combined, and
boundary-distance combined. The weighted coefficients
and significance tests show that contiguity best represents
the spatial relationship in the distribution of wildand
fires. Distance introduces a scaling effect which enhances the magnitude of Moran's I coefficient of spatial
autocorrelation.
A Low Pressure Soaker Hose Containment System for Wildland Fires
Authors: Kanjanakunchorn S , Woodard PM , McCornick PG , McDonald H
Published: October 2005

Water is frequently used to contain wild or
prescribed fires in a wildland situation. In this paper, we
show why the commonly-available, relatively inexpensive garden-type soaker hose can be effectively used to
contain fires. We present results on such performance
characteristics as: water pressure, height of water spray
and water volume as distance from pump increases. A
Wajax Mark 111 pump, 3.8 cm dia (1.5") lined fire hose
and RCR-strata soaker hoses were used in all tests. Also,
using commonly accepted engineering principles and
equations, we present the optimal design when the above
materials are used.
A 10-Year Evaluation of Prescribed Winter Burns in Uneven-Aged Stands of Pinus-Taeda L and P. Echinata Mill - Woody Understorey Vegetation Response
Authors: Cain MD
Published: October 2005

The effects of burning cycles and pine basal area levels were assessed on natural pine regeneration and hardwood development in uneven-aged stands of loblolly and shortleaf pines (Pinus taeda L. and P. echinata Mill.). The treatments included an unburned control and prescribed winter burns at 3-, 6-, and 9-yr intervals. Basal area treatments were 9, 14, 18, and 23 m2 ha-1 for the merchantable-pine component and were maintained on a 6-yr cutting cycle using single-tree selection. Ten years after the study was initiated, density and quadrat stocking of pine regeneration were negatively correlated with overstorey basal area. The 6-yr burning cycle had higher pine density and better quadrat stocking of pine regeneration compared with any other bum treatment mainly because the 6-yr burning cycle coincided with a bumper pine seedcrop and the 6-yr cutting cycle. Recurring fires tended to result in reduced size of hardwood competition but had less impact on hardwood density. When considering a prescribed burning program in uneven-aged stands of loblolly and shortleaf pines, more attention should be given to density, quadrat stocking, and size of established pine regeneration and to expected seedcrops rather than to the prosecution of rigid burning schedules.
Fire Behavior Experiments in Mixed Fuel Complexes
Authors: Catchpole EA , Catchpole WR , Rothermel RC
Published: October 2005

A series of laboratory fire experiments were conducted in fuel beds consisting of either excelsior (wood wool), or 6.35 mm sticks, or a mixture of these. Tests were done both with and without wind. Various characteristics of the fire, including rate of spread and fireline intensity, were compared with predictions from the Rothermel model. The behavior of the mixed fuel fires, compared to that of the fires in the constituent fuels, did not agree well with the predictions of the model. We conclude that, in order to model the behavior of fire in mixed fuels, the Rothermel model needs modification.
Predicting Pinus ponderosa Mortality From Dormant Season and Growing-Season Fire Injury
Authors: Harrington MG
Published: October 2005

Understory prescribed burning was conducted in an immature Pinus ponderosa (ponderosa pine) stand in southwestern Colorado during three seasons, late spring, midsummer, and autumn. Tree mortality from various levels of crown scorch was compared for the different seasons of injury. A total of 526 trees of different sizes, with crown scorch ranging from 20 to 100%, were monitored annually for 10 years. Over 80% of the 10-year mortality from injury in all three seasons had occurred by year 3, with over 90% occurring by year 4. Mortality of trees scorched in the spring and summer was about 2.5 times greater than that in the autumn for similar crown damage. Most trees larger than 18 cm in diameter survived autumn injury, even with greater than 90% scorching. Following spring and summer injury, trees smaller than 10 cm in diameter died readily with greater than 50% scorching, but about 90% crown scorch was required by large trees to be lethal. A logistic regression model was developed to predict the probability of mortality given tree size, scorch class, and season of injury. Because mortality was similar within scorch classes less than 90%, they were combined into a single class. Scorch thresholds with large increases in mortality occurred at 90% and 100% crown scorch. The season variable includes two groups, dormant (autumn) and growing (spring and summer). Use of this model to predict mortality of immature P. ponderosa is appropriate where stand, fuel, and fire conditions resemble those of this study.
Wildfire in the Yugoslav Area and Eastern Mediterranean Region
Authors: Reeves HC
Published: October 2005

Forest exploitation by humans and their activities has taken place throughout the Mediterranean Basin for centuries. The area formerly called Yugoslavia located on the Balkan Peninsula, is fairly representative of fire conditions in the eastern Mediterranean Sea. Over the centuries different ethnic groups have altered the forest through utilization and the grazing of domestic animals. Possibly the most serious influence has been fire, both man-caused and natural. The author has examined fire in different countries of the region and made some suggestions which might help reduce the number of wildfires and aid in the suppression of those which do occur.
Wildfire Effects on Forest Floor and Surface Soil in a Table Mountain Pine-Pitch Pine Forest
Authors: Groeschl DA , Johnson JE , Smith DW
Published: October 2005

Wildfire plays a dominant role in creating die environmental and biological conditions necessary for the natural regeneration of mixed Pinus pungens Lamb. (Table Mountain pine)-Pinus rigida Mill. (pitch pine) forests. This study of forest floor and surface soil properties following a mid-July wildfire in these forests in the Shenandoah National Park revealed significant reductions in nutrient contents. Prolific regeneration of the pines occurred following the fire, with over 9,000 seedling/ha tallied in high severity areas, compared with less than 800 seedlings/ha in unburned areas. It is hypothesized that fire degrades site quality and sets back the site succession process so that the pines are better able to compete with invasive, xeric-site deciduous species like oaks and maples. Adjacent, unburned xeric-site oak forests dominate on more moist and fertile sites.
Variation of Live and Dead Fine Fuel Moisture in Pinus radiata Plantations of the Australian-Capital-Territory
Authors: Pook EW , Gill AM
Published: October 2005

A study was made of the variation in moisture content of fine dead fuel (FFM) in relation to 1) differences of fuel type (needles, leaves, twigs, bark), 2) different fuel locations (dead canopy and surface litter), 3) contrasting management of plantations (unthinned-unpruned vs thinned-pruned) and 4) environmental factors (air temperature (T) and relative humidity (H); moisture content of duff (D) and topsoil (S)). The variation of live (green needle) fine fuel moisture content (LFMC) in relation to needle age, canopy location (shaded vs unshaded) and season was also studied in Pinus radiata D. Don plantations over 2 years. Mean differences of moisture content between the several types of fuel exposed to the same atmospheric conditions were generally significant and ranged from 0.6% (pine twigs vs eucalypt twigs) up to 2.8% oven dry weight (ODW) (eucalypt bark vs recently cast pine needles). T and H were highly correlated between study sites in pine plantations and an official meteorological station at Canberra airport, 15 km away. In the pine plantations, mid afternoon moisture contents of pine needle litter (litter FFMs) were mostly higher than moisture contents of dead needles in canopies (aerial FFMs); the mean differences between litter FFMs and aerial FFMs were statistically significant. FFMs in the unthinned-unpruned plantation were also generally higher than those in the thinned-pruned plantations. Regression analyses of relationships between FFM and environmental variables showed that T and H in combination explained a large proportion of the variation in aerial FFM but much less of the variation in litter FFM. However, the inclusion of either D or S in multiple regression models accounted for significant amounts of the variation in litter FFM. LFMC decreased with needle age and, for full-grown needles, was up to 25% (ODW) higher in shaded compared to unshaded canopy locations. Seasonal patterns of change in LFMC of full-grown needles were not well defined. Variation in the parameters and the precision of FFM regression relationships between fuel locations and stands with contrasting management demonstrate the site specificity and limitations of empirical FFM models. The results suggest that for prediction of aerial FFM, models based on a combination of T and H are most appropriate; while, models that include a soil moisture variable may predict FFM of litter fuels more accurately. However, the intrinsic variation in FFM revealed in this study indicates that such models, although providing a useful guide, may not predict FFM with the accuracy required for fire behaviour models during high fire danger weather - when fuel moistures are low.
Wildfire Activity in the Mallee Shrubland of Victoria, Australia
Authors: Krusel N , Packham D , Tapper N
Published: October 2005

McArthur's Fire Danger Indices were developed originally as empirical models to describe fire danger in dry sclerophyll forest and grasslands of Australia. These indices are now used widely in southeastern Australia for fire danger rating and as a guideline for the issue of fire weather warnings. Nine years of historical fire reports, fire danger indices and meteorological information have been analysed objectively to develop a model to predict days of high fire activity in the mallee shrubland of northwestern Victoria. Tested on two years of independent data it was found that the use of a simple model utilising standard meteorological observations rather than the McArthur Forest Fire Danger Index reduced the false alarm rate from 98.4% to 96.7%. Although apparently a small reduction in false alarm rate, over a two year period days of high fire activity predicted incorrectly were reduced dramatically by 345 days.
Fire Regime and the Abundance of Red Pine
Authors: Flannigan MD
Published: October 2005

Red pine (Pinus resinosa Ait.) is a fire-dependent species. This study examines the relationship between the fire regime and the abundance of red pine. The fire regime is represented by components of the Canadian Fire Weather Index System and outputs from the Canadian Fire Behavior Prediction System as well as the average area burned and the percentage of conifers of each forest section. Extreme as well as averages values were used in this analysis as a large forest fire is a rare event that can occur on only a few days of the year under extreme fire weather conditions. Results from a forward-stepwise regression explained about 70% of die variance in red pine volume (abundance) data. Variables selected in the regression analysis included extreme headfire intensity, area burned and average drought code. These results suggest that abundance of red pine and other fire affected tree species is directly related to the aspects of the fire regime such as fire intensity.
Double Sampling Increases the Efficiency of Forest Floor Inventories for Arizona Ponderosa Pine Forests
Authors: Fule PZ , Covington WW
Published: October 2005

Stand and natural fuel conditions were sampled in ponderosa pine forests in northern and central Arizona to develop predictive fuel depth and loading equations. Litter and duff depths can be estimated from measurements of stand density (basal area, stand density index). Although woody fuel loading did not correlate well with stand variables, correlations were found among loadings of different woody fuel size classes, so that results from a planar intersect tally of certain single woody fuel size classes may be used to predict the loadings in certain other size classes. The relatively low precision of estimates from these predictive equations can be substantially increased by applying them in a double sampling scheme. Making use of these predictive relationships, managers can devise simple, rapid, arid cost-effective fuel inventories that focus on the fuel category of interest. Fuel loads can be estimated at a desired precision with reduced investment of time and funds compared to a more comprehensive direct fuel inventory.
Postfire Defoliation Response of Agropyron spicatum and Sitanion hystrix
Authors: Jirik SJ , Bunting SC
Published: October 2005

Prescribed fire is an important management tool to increase herbaceous productivity and maintain seral communities of Intermountain sagebrush grasslands. Currently, pastures treated with prescribed fire are rested from livestock grazing before burning to allow fine fuel accumulation, and rested a full year following burning to restore bunchgrass vigor. This study examined the post-fire defoliation response of Agropyron spicatum and Sitanion hystrix to three different defoliation treatments: an early season defoliation during the boot phenological stage, late season defoliation after seedset, and non-defoliation. Plant response to these defoliation timings was compared to determine the amount of non-use required to restore vigor to these species following fire. Mortality was low for late and non-defoliated plants of both species. Results indicate no differences between late season and non-defoliated plants for biomass production, basal area, or culm number for Agropyron. No differences in Sitanion culm number resulted between the late and non defoliated treatments. Sitanion biomass production differed between late and non-defoliated treatments at Emmett, but not at Craters of the Moon. Basal area and culm number of late and non-defoliated plants of both species increased as compared to the first post-burn season.
Effect of Prescribed Burning on the Ectomycorrhizal Infectivity of a Forest Soil
Authors: Herr DG , Duchesne LC , Tellier R , Mcalpine RS , Peterson RL
Published: October 2005

Ectomycorrhizae formation, seedling health index, and seedling survival were assessed for two-year-old nursery-grown seedlings of Pinus resinosa and Pinus strobus two months after planting in clear-cuts that had received prescribed burning under different fire intensities. Controls consisted of seedlings planted in unburned clear-cuts. Fire intensity positively correlated with percent ectomycorrhizal roots for P. strobus but not for P. resinosa. Seedling health index and survival were highest in burned-over sites as compared to control sites for both pine species. Fire intensity correlated with seedling health index for P. strobus but not for P. resinosa. Fire intensity correlated with seedling survival for both species. Colonization of seedlings by ectomycorrhizal fungi did not correlate with seedling health index or seedling survival. P. resinosa seedlings planted in burned-over sites had a smaller number of lateral roots per unit length primary/secondary roots compared to seedlings planted in control plots.
Predicting the Height to Live Crown Base in Plantations of Four Boreal Forest Species
Authors: Mc Alpine RS , Hobbs MW
Published: October 2005

A critical parameter for the initiation and propagation of a crown fire in the boreal forest is the height to the base of the live crown. The initiation of a crown fire requires that the surface fire intensity must be sufficient to ''jump'' the gap between the forest floor and the live crown and ignite crown fuels. The greater the height of the live crown base, the more intense the surface fire must be to induce a crown fire. Plantation forest fuels tend to be more structured and have less variability than naturally regenerated areas, allowing prediction of the height of the live crown base to be made from commonly available stand parameters. Plantations of four commonly planted boreal forest species were sampled over a variety of age classes to determine a predictive relationship for height to live crown base. Height to live crown base can be predicted from stand height and density for Pinus banksiana (jack pine), Pinus resinosa (red pine), Picea mariana (black spruce), and Picea glauca (white spruce). In addition to predicting the height to live crown base, parameters within the equations lead to other observations. Crown foliar fuel loading does not change with stand height following crown closure in red pine but in the other three species crown fuel load increases as the stand grows taller.
Fire Planning for Wildlife Management - a Decision-Support System for Nadgee-Nature-Reserve, Australia
Authors: Baird IA , Catling PC , Ive JR
Published: October 2005

This paper describes a decision support system for generating fire management plans which address predefined wildlife management objectives for a nature conservation reserve. Given limited knowledge of how low intensity fire would affect wildlife species, the expert reasoning of researchers was used to postulate fire response curves showing how high intensity fire affects vegetation structure and hence wildlife population density through time. These fire response curves and knowledge of the habitat preferences of wildlife species provided the best available information upon which to frame decision rules advocating prescribed burning at low intensity to manipulate wildlife habitat. Decision rules were also framed for protecting recreation sites, limiting fire spread, and reducing the risk of wildfire ignition. Once the decision rules were quantified, the LUPIS land use planning and information system was used to derive and map burning options reflecting different wildlife management strategies.
Modeling Smoldering Emissions From Prescribed Broadcast Burns in the Pacific-Northwest
Authors: Ferguson SA , Hardy CC
Published: October 2005

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.
Comparisons of Particulate-Emissions and Smoke Impacts From Presettlement, Full Suppression, and Prescribed Natural Fire Period in the Selway-Bitterroot Wilderness
Authors: Brown JK , Bradshaw LS
Published: October 2005

Total particulate matter (PM) emissions were estimated for recent fires (1979-1990) and the presettlement period (prior to 1935) in the Selway-Bitterroot Wilderness (SBW) in Idaho and Montana. Recent period emissions were calculated by 10-day periods for surface fire and crown fire based on estimates of percentage fuel consumption and emission factors applied to fuel models constructed for each of eight fire regime types. Presettlement emissions were derived from estimates of historical fire occurrence. The occurrence and duration of smoke episodes in a large adjoining valley were documented for a 30-year period (1960-1990). During the presettlement period, smoke emissions were 1.3 times greater than during the recent period. Dispersion modeling indicated that during presettlement, visibility averaged 25% less than during the recent period. Valley smoke episodes ranged from 2 to 10 days in length and were 1.3 times more likely to occur during the presettlement period. Regression analysis indicated that a valley smoke event was likely above a 10-day PM threshold of 1,500 Mg. Characteristics of smoke episodes were described for none, minor, moderate, and extreme smoke categories. Occurrence of smoke did not differ between periods of full fire suppression and prescribed natural fire management.
Comparing the Prescribed Natural Fire Program With Presettlement Fires in the Selway-Bitterroot Wilderness
Authors: Brown JK , Arno SF , Barrett SW , Menakis JP
Published: October 2005

The severity and extent of recent fires (1979-1990) were compared with that of presettlement fires (pre-1935) by eight major forest types in the Selway-Bitterroot Wilderness (SBW) in Idaho and Montana. Presettlement fire intervals were determined for estimating area burned. Presettlement annual area burned for the entire SBW was 4,290 ha by stand replacement fire and 4,310 ha by nonlethal understory fire. All recent period fires>4 ha were mapped using a GIS system. Area burned was determined by the fire severity classes: crowning, lethal surface, nonlethal surface, and no burning. Annual area burned averaged 2,780 ha by stand replacement and 2,270 by understory fire. Area burned during presettlement was 1.7 times that during the recent period. During the presettlement period, area burned by stand replacement and nonlethal understory fire was 1.5 and 1.9 times greater respectively than during the recent period.
Changes in Soil Nutrients Following Burning Burning of Dry Tropical Savanna
Authors: Singh RS
Published: October 2005

The effects of fire in dry tropical savanna ecosystems on plant available nutrients (nitrate-N, ammonium-N and phosphate - P); N - mineralization rate; soil microbial biomass C, N and P; canopy biomass and root biomass were studied during selected months. Parameters studied were the vegetative, reproductive, flowering and fruiting, fruitfall, early senescence and late senescence. The values of nitrate-N, ammonium-N and phosphate - P, N- mineralization and nitrification rate; microbial C, N and P, canopy biomass and root biomass indicated significant difference due to month and treatment, but were not significant due to year. Following fire, the increase in the build up of microbial biomass in the dry season and canopy growth and N-mineralization rate in the wet season are nutrient conserving mechanisms that prevent nutrient loss. Therefore fire can be a management tool for better productivity and nutritive quality in dry tropical environments.
Estimating the Value of Reducing Fire Hazards to Old-Growth Forests in the Pacific-Northwest - a Contingent Valuation Approach
Authors: Loomis J , Gonzalescaban A
Published: October 2005

To expand the scope of natural resource values included in USDA Forest Service fire management analysis system, a mail survey of Oregon households regarding their willingness to pay for a fire prevention and control program on northern spotted owl critical habitat units in Oregon was performed. Using the voter referendum format, annual willingness to pay of $77 per Oregon household was estimated. This translates into a value of $28 per acre protected. The contingent valuation method may provide a promising avenue for incorporating society's broadening concern about biodiversity and natural values into public land management agencies fire management decisions.
The Effects of Repeated Prescribed Burning on Pinus ponderosa Growth
Authors: Peterson DL , Sackett SS , Robinson LJ , Haase SM
Published: October 2005

The effect of repeated prescribed burning on long term growth of Pinus ponderosa in northern Arizona was examined. Fire treatments for hazard reduction were initiated in 1976, acid growth was evaluated in 1988 for fire rotations of 1, 2, 4, 6, 8, and 10 years. Dendroecological analysis shows that there were only small changes in tree growth (compared to controls) in the first few years after the initial fire treatment despite large fuel reductions and thinning, and that annual precipitation was positively correlated with growth. Moderate changes in growth relative to that of control trees were apparent after 1984. The 1-, 2-, 8-, and 10-year treatments had lower growth than controls after this date, while 4- and 6-year treatments had slightly higher growth. Although additional data are needed to determine long term growth effects in the longer fire rotations, a fire treatment interval of 4 to 6 years appears to provide adequate fuel reduction without reducing long term growth in Southwestern P. ponderosa forests.
A General Mathematical Framework for Modeling Two-Dimensional Wildland Fire Spread
Authors: Richards GD
Published: October 2005

This work considers the modelling of two dimensional fire spread for heterogeneous fuel and meteorological conditions. Differential equations are used as the modelling form, and a set of partial differential equations that describes fire growth in terms of the rate of spread at each point on the perimeter is derived. These equations require the specification of the rate of spread as a function of the variables affecting it, and form a general modelling framework into which such a function can be placed. To model the relationship between the rate of spread and its affecting factors an analysis of point source ignition fires for homogeneous fuel and meteorological conditions is made. Based on this analysis a spread rate model for heterogeneous conditions is proposed. The resulting differential equations require a sophisticated computer solution, however there are a number of nontrivial fire situations for which solutions can relatively easily be obtained, and example solutions are presented.
A Computer Algorithm for Simulating the Spread of Wildland Fire Perimeters for Heterogeneous Fuel and Meteorological Conditions
Authors: Richards GD , Bryce RW
Published: October 2005

This work describes a computer based technique for simulating the spread of wildland fire for heterogeneous fuel and meteorological conditions. The mathematical model is in the form of a pair of partial differential equations, and can model fuels whose fire perimeter for homogeneous conditions is any given shape, such as ellipses, double ellipses, lemniscates etc. Provided the fire does not attempt to burn into an already burnt out region, then the differential equations are easily solved and a simple method of solution is presented. To identify regions that are internal to the fire perimeter an algorithm that uses the turning number of a point in the plane relative to the fire perimeter is used. The algorithm is found to be reliable, and allows for the simulation of highly complex fire scenarios in a reasonable time. Example simulations are presented that involve variations in fuel, barriers, wind direction changes and multiple fires.
A Logit Model for Predicting the Daily Occurrence of Human Caused Forest-Fires
Authors: Garcia CV , Woodard PM , Titus SJ , Adamowicz WL , Lee BS
Published: October 2005

The logit model was used to predict the number of fire-days in the Whitecourt Forest of Alberta. The database used included fire (1) and no-fire (0) observations for fire season days between April and October for the 1986 through 1990 period. There were 8,009 observations during this period of which 157 were fire observations. Using four variables, we were able to predict 79.0% of the fire-days and 81.5% of the no-fire-days. The model, Zi=-8.5171+7.6590xAREAi+0.7367xDISTRICTi+2.0478xBUIi+3.9563xISIi, failed to predict 37 of the fire-days and produced 29 ''false alarms''. When this model was tested on fire occurrence data from the Whitecourt Forest for 1991 and 1992 fire seasons it was correct 74.1% of the time. The management implications and limitations of this study are also discussed in this paper.
Effects of Fire on Soil Macroinvertebrates in a Mediterranean Phryganic Ecosystem
Authors: Sgardelis SP , Pantis JD , Argyropoulou MD , Stamou GP
Published: October 2005

The effect of a summer wildfire on the abundance and community composition of soil macroinvertebrates of a phryganic ecosystem was studied. The numerical responses of macroinvertebrates to fire were variable, most notably the reduction of the saprophagous fauna. The magnitude of the changes in abundance due to fire was comparable or even lower than the variations imposed by the seasonality of the mediterranean climate. fire did not seem to affect strongly the community composition of the soil inhabiting fauna, but caused considerable changes in the composition of the litter-dwellers. Furthermore, seasonal changes in community composition were less pronounced in the burnt site compared to those in the control. The observed effects of fire should be attributed to the destruction of the litter layer and the above ground vegetation cover, rather than to the immediate death of the animals, since most of them were absent from the upper soil layers during summer, that is when fire occured.