Prescribed Burning of Thinning Slash in Regrowth Stands of Karri (Eucalyptus diversicolor) .2. Nitrogen Budgets in Pre- and Post-Burn Fuel

1997 ◽  
Vol 7 (1) ◽  
pp. 41 ◽  
Author(s):  
AM O'Connell ◽  
WL McCaw
Keyword(s):  
Prescribed Burning ◽  
Fire Hazard ◽  
Weather Conditions ◽  
Moderate Intensity ◽  
Litter Layer ◽  
Nitrogen Budgets ◽  
Dryness Index ◽  
Soil Dryness ◽  
Fuel Components ◽  
Eucalyptus Diversicolor

Changes in nitrogen content of fuel were investigated following eight low to moderate intensity experimental fires conducted under a range of fire weather conditions in a recently thinned 22-year-old regrowth stand of karri (Eucalyptus diversicolor F. Muell) in Western Australia. The average amount of dead fuel < 100 mm in diameter present before burning was 76 t/ha (range 50 to 107 t/ha). The amount of live fuel was small, with a mean of 4 t/ha. Forest floor litter, consisting of fresh and partly decomposed dead leaves and fine twigs (< 6 mm diameter) contributed about 30% of total fuel weight, and wood fractions > 6 mm in diameter contributed about 60%. Remaining fuel was made up of small twigs, bark and leaves added from the thinning operation. Distribution of nitrogen in fuel fractions differed markedly from distribution of fuel weights with more than 60% of fuel-nitrogen in the litter and only about 25% of fuel-nitrogen in wood greater than 6 mm diameter. Following fire, the average amounts of nitrogen in all fuel fractions was reduced. The majority of nitrogen in wood fractions and in bark and leaves was volatilized during the fires (range 55% to 99%), while on average only about 38% of the nitrogen in litter was volatilized. The amount of nitrogen lost from dead fuel differed between the experimental fires (range 50 to 180 kg/ha) and was significantly related to the total amount of fuel consumed (r2 = 0.92). Fuel consumption and nitrogen volatilization increased as the Soil Dryness Index increased and as litter moisture decreased. Nitrogen losses due to burning were small relative to total stores of nitrogen in soil (about 6000 kg/ha) but for the most intense fires were significant in relation to amounts in growing vegetation and surface soil. Burning when moisture content of the litter profile exceeds 90% will reduce combustion of the litter layer. Burning under these conditions allows effective reduction in the flash fuel components located in the upper parts of the fuel bed while retaining much of the nutrient-rich lower strata of fuel. Burns of this type provide effective fire hazard reduction while favouring conservation of nitrogen stored in the litter layer.

Prescribed Burning of Thinning Slash in Regrowth Stands of Karri (Eucalyptus diversicolor) .1. Fire Characteristics, Fuel Consumption and Tree Damage

1997 ◽  
Vol 7 (1) ◽  
pp. 29 ◽  
Author(s):  
WL McCaw ◽  
RH Smith ◽  
JE Neal
Keyword(s):  
Fuel Consumption ◽  
Tree Mortality ◽  
Prescribed Burning ◽  
Flame Length ◽  
Moderate Intensity ◽  
Litter Layer ◽  
Tree Damage ◽  
Stem Damage ◽  
Fire Characteristics ◽  
Eucalyptus Diversicolor

'Fire characteristics, fuel consumption and fire-caused tree damage were investigated for ten low to moderate intensity fires in thinning slash fuel in 22-year-old karri (Eucalyptus diversicolor F. Muell) regrowth in Western Australia. Eight fires were burnt in spring and two in autumn. Most fires consumed greater than 80 per cent of dead fuel < 25 mm in diameter and between 40 per cent and 80 per cent of the litter layer. The total amount of litter and dead fuel < 100 mm in diameter consumed during burning ranged from 24 to 79 t ha-1 (31-89 per cent). Actual and percentage consumption of fuel < 100 mm diameter were inversely related to the moisture content of the litter profile. Fireline intensities determined from flame length estimates ranged from 90 kW m-1 to 2820 kW m-1. Damage to retained trees included stem wounding, crown death and complete death of the stem. Burning in spring when the litter profile was moist resulted in damage to the lower stems of up to 80 trees ha-1, with damage affecting an average of 3 m2 ha-1 of the retained basal area of 19.5 m2 ha-1. The incidence of stem damage following spring burning was considerably greater when the litter layer was dry. Autumn burning resulted in extensive stem damage and tree mortality and is not therefore recommended. Log debris within 1 m of trees significantly increased the probability of fire-caused damage, and wounds tended to be larger on trees that had debris nearby. The incidence of damage from burning was directly related to the quantity of fuel consumed and heat release per unit area, but was not significantly correlated with fireline intensity. A prescription for burning thinning slash during spring conditions is presented.

A review of prescribed burning effectiveness in fire hazard reduction

2003 ◽  
Vol 12 (2) ◽  
pp. 117 ◽  
Author(s):  
Paulo M. Fernandes ◽  
Hermínio S. Botelho
Keyword(s):  
Prescribed Fire ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Accumulation Rate ◽  
Fire Suppression ◽  
Fire Hazard ◽  
Weather Conditions ◽  
Management Tool ◽  
Adequate Treatment ◽  
Hazard Reduction

Wildfire hazard abatement is one of the major reasons to use prescribed burning. Computer simulation, case studies, and analysis of the fire regime in the presence of active prescribed burning programs in forest and shrubland generally indicate that this fuel management tool facilitates fire suppression efforts by reducing the intensity, size and damage of wildfires. However, the conclusions that can be drawn from the above approaches are limited, highlighting the need for more properly designed experiments addressing this question. Fuel accumulation rate frequently limits prescribed fire effectiveness to a short post-treatment period (2–4 years). Optimisation of the spatial pattern of fire application is critical but has been poorly addressed by research, and practical management guidelines are lacking to initiate this. Furthermore, adequate treatment efforts in terms of fire protection are constrained by operational, social and ecological issues. The best results of prescribed fire application are likely to be attained in heterogeneous landscapes and in climates where the likelihood of extreme weather conditions is low. Conclusive statements concerning the hazard-reduction potential of prescribed fire are not easily generalised, and will ultimately depend on the overall efficiency of the entire fire management process.

scholarly journals Prescribed burning in a mediterranean-climate region mitigates the disturbance by bushfire to a critical food resource for an endangered bird, the Carnaby’s cockatoo

Fire Ecology ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Valerie S. Densmore ◽  
Emma S. Clingan
Keyword(s):  
Seed Production ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Fire Hazard ◽  
Food Resource ◽  
Management Tool ◽  
Fire Intensity ◽  
Prescribed Burns ◽  
Low Intensity ◽  
Percentage Survival

Abstract Background Prescribed burning is used to reduce fire hazard in highly flammable vegetation types, including Banksia L.f. woodland that occurs on the Swan Coastal Plain (SCP), Western Australia, Australia. The 2016 census recorded well over 1.9 million people living on the SCP, which also encompasses Perth, the fourth largest city in Australia. Banksia woodland is prone to frequent ignitions that can cause extensive bushfires that consume canopy-stored banksia seeds, a critical food resource for an endangered bird, the Carnaby’s cockatoo (Calyptorynchus latirostris, Carnaby 1948). The time needed for banksias to reach maturity and maximum seed production is several years longer than the typical interval between prescribed burns. We compared prescribed burns to bushfires and unburned sites at three locations in banksia woodland to determine whether low-intensity prescribed burns affect the number of adult banksias and their seed production. Study sites were matched to the same vegetation complex, fire regime, and time-since-fire to isolate fire intensity as a variable. Results Headfire rates of spread and differenced normalized burn ratios indicated that prescribed burning was generally of a much lower intensity than bushfire. The percentage survival of adult banksias and their production of cones and follicles (seeds) did not decrease during the first three years following a prescribed burn. However, survival and seed production were significantly diminished followed high-intensity bushfire. Thus, carrying capacity for Carnaby’s cockatoo was unchanged by prescribed burning but decreased markedly following bushfire in banksia woodland. Conclusions These results suggest that prescribed burning is markedly different from bushfire when considering appropriate fire intervals to conserve canopy habitats in fire-resilient vegetation communities. Therefore, low-intensity prescribed burning represents a viable management tool to reduce the frequency and extent of bushfire impacts on banksia woodland and Carnaby’s cockatoo.

scholarly journals Opportunities for winter prescribed burning in mixed conifer plantations of the Sierra Nevada

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Robert A. York ◽  
Jacob Levine ◽  
Kane Russell ◽  
Joseph Restaino
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Prescribed Burning ◽  
Winter Season ◽  
Basal Area ◽  
Weather Conditions ◽  
Shrub Cover ◽  
Mixed Conifer ◽  
Planted Forests ◽  
Conifer Plantations

Abstract Background Young, planted forests are particularly vulnerable to wildfire. High severity effects in planted forests translate to the loss of previous reforestation investments and the loss of future ecosystem service gains. We conducted prescribed burns in three ~35-year-old mixed conifer plantations that had previously been masticated and thinned during February in order to demonstrate the effectiveness of winter burning, which is not common in the Sierra Nevada, California. Results On average, 59% of fine fuels were consumed and the fires reduced shrub cover by 94%. The average percent of crown volume that was damaged was 25%, with no mortality observed in overstory trees 1 year following the fires. A plot level analysis of the factors of fire effects did not find strong predictors of fuel consumption. Shrub cover was reduced dramatically, regardless of the specific structure that existed in plots. We found a positive relationship between crown damage and the two variables of Pinus ponderosa relative basal area and shrub cover. But these were not particularly strong predictors. An analysis of the weather conditions that have occurred at this site over the past 20 years indicated that there have consistently been opportunities to conduct winter burns. On average, 12 days per winter were feasible for burning using our criteria. Windows of time are short, typically 1 or 2 days, and may occur at any time during the winter season. Conclusions This study demonstrates that winter burning can be an important piece of broader strategies to reduce wildfire severity in the Sierra Nevada. Preparing forest structures so that they can be more feasible to burn and also preparing burn programs so that they can be nimble enough to burn opportunistically during short windows are key strategies. Both small landowners and large agencies may be able to explore winter burning opportunities to reduce wildfire severity.

scholarly journals Modeling Drying of Degenerated Calluna vulgaris for Wildfire and Prescribed Burning Risk Assessment

Forests ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 759 ◽  
Author(s):  
Torgrim Log
Keyword(s):  
Mathematical Model ◽  
Numerical Model ◽  
Mass Loss ◽  
Diffusion Coefficients ◽  
Prescribed Burning ◽  
Fire Hazard ◽  
Fire Risk ◽  
Calluna Vulgaris ◽  
Fire Danger ◽  
Drying Process

Research highlights: Moisture diffusion coefficients for stems and branches of degenerated Calluna vulgaris L. have been obtained and a mathematical model for the drying process has been developed and validated as an input to future fire danger modeling. Background and objectives: In Norway, several recent wildland–urban interface (WUI) fires have been attributed to climate changes and accumulation of elevated live and dead biomass in degenerated Calluna stands due to changes in agricultural activities, i.e., in particular abandonment of prescribed burning for sheep grazing. Prescribed burning is now being reintroduced in these currently fire prone landscapes. While available wildfire danger rating models fail to predict the rapidly changing fire hazard in such heathlands, there is an increasing need for an adapted fire danger model. The present study aims at determining water diffusion coefficients and develops a numerical model for the drying process, paving the road for future fire danger forecasts and prediction of safe and efficient conditions for prescribed burning. Materials and methods: Test specimens (3–6 mm diameter) of dead Calluna stems and branches were rain wetted 48 h and subsequently placed in a climate chamber at 20 °C and 50% relative humidity for mass loss recordings during natural convection drying. Based on the diameter and recorded mass versus time, diffusion coefficients were obtained. A numerical model was developed and verified against recoded mass loss. Results: Diffusion coefficients were obtained in the range 1.66–10.4 × 10−11 m2/s. This is quite low and may be explained by the very hard Calluna “wood”. The large span may be explained by different growth conditions, insect attacks and a varying number of years of exposure to the elements after dying. The mathematical model described the drying process well for the specimens with known diffusion coefficient. Conclusions: The established range of diffusion coefficients and the developed model may likely be extended for forecasting moisture content of degenerated Calluna as a proxy for fire danger and/or conditions for efficient and safe prescribed burning. This may help mitigate the emerging fire risk associated with degenerated Calluna stands in a changing climate.

Spring fire effects on two Aristida/Bothriochloa native pastures in central Queensland, Australia

2018 ◽  
Vol 40 (5) ◽  
pp. 485
Author(s):  
R. G. Silcock ◽  
T. J. Hall ◽  
P. Jones ◽  
P. G. Filet ◽  
J. Douglas
Keyword(s):  
Prescribed Burning ◽  
Woody Plant ◽  
Marked Change ◽  
Ground Cover ◽  
Weather Conditions ◽  
Fire Effects ◽  
Heteropogon Contortus ◽  
Eucalypt Woodlands ◽  
Native Pastures ◽  
The Many

Controlled burns are commonly used to suppress woody plant regrowth and to remove accumulated unpalatable pasture from rangelands and occasionally to alter pasture composition in native pastures in central Queensland, Australia. Outcomes can be somewhat unpredictable and short-term, and reliable evidence is needed to confirm the likely long-term efficacy of such fires. We imposed a regime of repeated spring burns on native Aristida/Bothriochloa pastures growing in two contrasting eucalypt woodlands of central Queensland to determine the effects on pasture composition, ground cover, landscape stability and woody plant recruitment, all in the absence of grazing. The sites selected were a silver-leaved ironbark (Eucalyptus melanophloia F.Muell.) woodland and a poplar box (E. populnea F.Muell.) woodland. Weather conditions precluded spring burns in 3 years out of 7 at the silver-leaved ironbark site and in 2 years out of 8 at the poplar box site. The burn intensity was variable, and frequent fires produced a marked change in abundance of only a few pasture species. Depending on the site, fires significantly increased the frequency of Enneapogon spp., Bothriochloa bladhii (Retz.) S.T.Blake and Dichanthium sericeum (R.Br.) A.Camus and reduced the frequency of some minor components such as Cymbopogon spp., Panicum effusum R.Br., Cenchrus ciliaris L. and, ephemerally, that of some forbs. Contrary to expectation, only Aristida calycina R.Br. declined in abundance among the many Aristida species present, and the abundance of Heteropogon contortus (L.) P.Beauv. ex Roem. & Schult. barely increased under regular spring fires. The total germinable seeds of herbaceous species in the soil each spring was significantly reduced by burning in the previous spring. Repeated spring fires rarely reinforced any initial change induced by burning, and slightly lowered average ground cover as well as various indices of landscape stability and ecosystem functionality. Changes produced were not always consistent across the two communities. Though prescribed burning is often important for maintaining grazing productivity and landscape values, very regular use is not recommended.

scholarly journals Saharan Hot and Dry Sirocco Winds Drive Extreme Fire Events in Mediterranean Tunisia (North Africa)

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 590 ◽  
Author(s):  
Chiraz Belhadj-Khedher ◽  
Taoufik El-Melki ◽  
Florent Mouillot
Keyword(s):  
Mediterranean Basin ◽  
Heat Waves ◽  
Fire Hazard ◽  
Weather Conditions ◽  
Burned Area ◽  
Summer Drought ◽  
Climate Conditions ◽  
The Mediterranean ◽  
The Mediterranean Basin ◽  
Extreme Fire

With hot and dry summers, the Mediterranean basin is affected by recurrent fires. While drought is the major driver of the seasonal and inter-annual fire distribution in its northern and mildest climate conditions, some extreme fire events are also linked to extreme winds or heat waves. The southern part of the Mediterranean basin is located at the driest range of the Mediterranean bioclimate and is influenced by Saharan atmospheric circulations, leading to extreme hot and dry episodes, called Sirocco, and potentially acting as a major contributor to fire hazard. The recently created fire database for Tunisia was used to investigate the ±10-day pre- and post-fire timeframe of daily weather conditions associated with fire events over the 1985–2006 period. Positive anomalies in minimum and maximum temperatures, negative anomalies in air relative humidity, and a preferential south-eastern wind during fire events were identified, which were characteristic of Sirocco winds. +7 °C anomalies in air temperature and −30% in relative air humidity were the critical thresholds for the most extreme fire conditions. In addition, meteorological anomalies started two days before fire events and lasted for three days after for large fires >400 ha, which suggests that the duration of the Sirocco event is linked with fire duration and final fire size. Lastly, the yearly number of intense Sirocco events better explained the inter-annual variability of burned area over the 1950–2006 period than summer drought based on Standardized Precipitation Evaporation Index (SPEI) indices.

scholarly journals Fuel mass and forest structure following stand-replacement fire and post-fire logging in a mixed-evergreen forest

2013 ◽  
Vol 22 (5) ◽  
pp. 652 ◽  
Author(s):  
Daniel C. Donato ◽  
Joseph B. Fontaine ◽  
J. Boone Kauffman ◽  
W. Douglas Robinson ◽  
Beverly E. Law
Keyword(s):  
High Intensity ◽  
Fire Hazard ◽  
Basal Area ◽  
Evergreen Forest ◽  
Moderate Intensity ◽  
Predictive Tool ◽  
Fuel Loads ◽  
Management Actions ◽  
Dead Trees ◽  
Standing Dead

Following severe wildfires, managing fire hazard by removing dead trees (post-fire logging) is an important issue globally. Data informing these management actions are relatively scarce, particularly how fuel loads differ by post-fire logging intensity within different environmental settings. In mixed-evergreen forests of Oregon, USA, we quantified fuel profiles 3–4 years after stand-replacement fire – assessing three post-fire logging intensities (0, 25–75, or >75% basal area cut) across two climatic settings (mesic coastal, drier interior). Stand-replacement fire consumed ~17% of aboveground biomass. Post-fire logging significantly reduced standing dead biomass, with high-intensity treatment leaving a greater proportion (28%) of felled biomass on site compared with moderate-intensity treatment (14%) because of less selective tree felling. A significant relationship between logging intensity and resulting surface fuels (per-hectare increase of 0.4–1.2Mg per square metre of basal area cut) indicated a broadly applicable predictive tool for management. Down wood cover increased by 3–5 times and became more spatially homogeneous after logging. Post-fire logging altered the fuel profile of early-seral stands (standing material removed or transferred, short-term increase in surface fuels, likely reduction in future large fuel accumulation), with moderate-intensity and unlogged treatments yielding surface fuel loads consistent with commonly prescribed levels, and high-intensity treatment resulting in greater potential need for follow-up fuel treatments.

Simulating the effectiveness of prescribed burning at altering wildfire behaviour in Tasmania, Australia

2018 ◽  
Vol 27 (1) ◽  
pp. 15 ◽  
Author(s):  
James M. Furlaud ◽  
Grant J. Williamson ◽  
David M. J. S. Bowman
Keyword(s):  
Prescribed Burning ◽  
Vegetation Type ◽  
Weather Conditions ◽  
Statistical Modelling ◽  
Fire Intensity ◽  
Fire Weather ◽  
Fire Behaviour ◽  
Large Area ◽  
Treatment Scenario ◽  
Wildfire Hazard

Prescribed burning is a widely accepted wildfire hazard reduction technique; however, knowledge of its effectiveness remains limited. To address this, we employ simulations of a widely used fire behaviour model across the ecologically diverse Australian island state of Tasmania. We simulate three broad scenarios: (1) no fuel treatment, (2) a maximal treatment, with the most possible prescribed burning within ecological constraints, and (3) 12 hypothetically more implementable state-wide prescribed-burning plans. In all simulations, we standardised fire-weather inputs to represent regionally typical dangerous fire-weather conditions. Statistical modelling showed that an unrealistically large maximal treatment scenario could reduce fire intensity in three flammable vegetation types, and reduce fire probability in almost every vegetation type. However, leverage analysis of the 12 more-realistic implementable plans indicated that such prescribed burning would have only a minimal effect, if any, on fire extent and that none of these prescribed-burning plans substantially reduced fire intensity. The study highlights that prescribed burning can theoretically mitigate wildfire, but that an unrealistically large area would need to be treated to affect fire behaviour across the island. Rather, optimisation of prescribed burning requires careful landscape design at the local scale. Such designs should be based on improved fire behaviour modelling, empirical measurement of fuels and analysis of actual wildfires.

A Computer-Based System for Fire Management in the Mountains of the Cape Province, South-Africa

1994 ◽  
Vol 4 (1) ◽  
pp. 17 ◽  
Author(s):  
DM Richardson ◽  
BW van Wilgen ◽  
DC Le Maitre ◽  
KB Higgins ◽  
GG Forsyth
Keyword(s):  
South Africa ◽  
Spatial Data ◽  
Prescribed Burning ◽  
Fire Management ◽  
Fire Hazard ◽  
Geographical Information ◽  
Water Yield ◽  
Catchment Management ◽  
Fire Control ◽  
Mountain Areas

This paper describes a Catchment Management System (CMS) that provides objective procedures for managing fire. Prescribed burning is carried out in the mountain catchments of the Cape Province, South Africa, to enhance water yield, to rejuvenate the indigenous shrubland vegetation, to reduce fire hazard and to control invasive alien plants. Fire is the only practical tool for achieving these aims in the mountainous terrain. Recent research has improved understanding of the response of these systems to fire, but managing fire to achieve goals is very difficult. The CMS comprises a central geographical information system for managing and processing spatial data, linked to personal computers with DBase IV data-bases and simple rule-based models for decision-making. Current applications are: prioritization of areas for burning, monitoring the success of fire management, mapping fire hazard for fire control planning, and the production of management summaries and statistics. This paper presents examples of these applications from three areas in the Cape Province with different management problems and priorities: the Kammanassie in the southern Cape, and the Kogelberg and Table Mountain areas in the western Cape.

Sign in / Sign up

Export Citation Format

Share Document