Relationship between fire-return interval and mulga (Acacia aneura) regeneration in the Gibson Desert and Gascoyne–Murchison regions of Western Australia

2014 ◽  
Vol 23 (3) ◽  
pp. 394 ◽  
Author(s):  
Bruce G. Ward ◽  
Thomas B. Bragg ◽  
Barbara A. Hayes
Keyword(s):  
Western Australia ◽  
Fire Size ◽  
Seedling Regeneration ◽  
Fire Return Interval ◽  
Return Interval ◽  
Population Average ◽  
Ring Analysis ◽  
Acacia Aneura ◽  
Fire Intervals ◽  
Landsat Satellite

A study of 26 burnt mulga (Acacia aneura) stands was conducted from 2003 to 2012 in the Gibson Desert and eastern Gascoyne–Murchison region of Western Australia to assess the effect of fire interval on seedling regeneration. Tree-ring analysis and Landsat satellite imagery identified mulga stands with fire intervals ranging from 3 to 52 years. Results show fire-return intervals less than 20 years produce 2–3-year-old seedling regeneration lower than 50% of the original adult stand population (average juvenile-to-adult ratio=0.49). In total, 6 of the 26 stands sampled had reburnt within 3 to 10 years of the previous burn, a consequence of increased plant growth associated with higher rainfall. For all fires, summer fires were larger and more frequent (24 of 35 fires recorded, median fire size=150km2) than spring fires (median fire size=91km2). This study emphasises the important role of fire in maintaining the diversity and vigour of the mulga–Triodia ecosystem but indicates a minimum fire-return interval of 26 years to maintain mulga populations.

A 400-year history of fires on lake islands in south-east Sweden

2010 ◽  
Vol 19 (8) ◽  
pp. 1050 ◽  
Author(s):  
Mats Niklasson ◽  
Igor Drobyshev ◽  
Tomasz Zielonka
Keyword(s):  
18Th Century ◽  
Fire Regime ◽  
Fire Suppression ◽  
Fire Spread ◽  
Small Islands ◽  
Fire Return Interval ◽  
Lake Ecosystems ◽  
Return Interval ◽  
Fire Disturbances ◽  
Fire Intervals

Island-lake ecosystems are suitable for testing scale dependence in forests disturbance theories thanks to differences in the potential for fire spread on islands and the mainland. We investigated past fire regime on the mainland and on islands in a large lake in south-east Sweden. We used dendrochronological methods to reconstruct fire disturbances on 18 small islands (0.04–24.1 ha) and in 43 sites in the surrounding 75-km2 landscape over the last 400 years. In the past, fires were frequent on both islands and mainland but not synchronised on an annual scale. Significant temporal changes occurred around the middle of the 18th century. Before 1750, fires were less frequent on islands than on the mainland (median fire return interval 58 v. 25 years respectively). However, an inversion of this pattern was observed during 1750–1860: islands showed even shorter fire intervals than mainland locations, suggesting additional and likely human-related source of ignitions (median fire return interval 15 v. 29 years respectively). A substantial decrease in fire activity in both islands and mainland was apparent in 1860–1890. We suggest that the present fire regime (the last 100 years) on the small islands is largely natural as fire suppression is not present there. The dynamic nature of the fire regime on islands still requires further studies: islands may, at times, attract lightning, humans with fire, or both.

scholarly journals Fuel age, weather and burn probability in Portugal

2012 ◽  
Vol 21 (4) ◽  
pp. 380 ◽  
Author(s):  
Paulo M. Fernandes ◽  
Carlos Loureiro ◽  
Marco Magalhães ◽  
Pedro Ferreira ◽  
Manuel Fernandes
Keyword(s):  
Fire Suppression ◽  
Weather Conditions ◽  
Age Dependency ◽  
Fire Return Interval ◽  
Return Interval ◽  
Free Interval ◽  
Burn Probability ◽  
Fire Atlas ◽  
Censored Observations ◽  
Fire Intervals

The relative influence of the factors acting on burn probability, namely fuel and weather, is not well understood, especially in Europe. We use a digital fire atlas (1975–2008) and apply survival analysis to individual fires (1998–2008) to describe how burn probability changes with fuel age in Portugal. The typical fire return interval and median fire-free interval vary regionally from 23 to 52 and 18 to 47 years. Increase of the hazard of burning with time is generally near-linear, denoting moderate fuel-age dependency, as in some other shrub-dominated Mediterranean environments. Analysis of complete fire intervals resulted in shorter fire return interval and higher fuel-age dependency of burn probability than findings that included censored observations. Increasingly severe weather conditions either expressed through fire size or by extreme fire danger concurrently decreased fuel-age dependency and selected older fuels. The results are discussed from the viewpoints of fire suppression and fuel treatments.

Dynamics of Perennial Plants in the Mulga (Acacia aneura F. Muell) Zone of Western Australia. I. Rates of Population Change.

1986 ◽  
Vol 8 (1) ◽  
pp. 18 ◽  
Author(s):  
HG Gardiner
Keyword(s):  
Environmental Factors ◽  
Plant Species ◽  
Western Australia ◽  
Population Change ◽  
Aerial Photographs ◽  
Normal Period ◽  
Macropus Rufus ◽  
Arid Rangelands ◽  
Acacia Aneura ◽  
Dynamics Of Populations

The dynamics of populations of six plant species and their responses to environmental factors were examined at Yeelirrie station in the Mulga Zone rangelands of Western Australia. Populations of plants were sampled using sequential maps drawn from low level aerial photographs of areas from which livestock had been removed and which were fenced either to exclude or permit grazing by kangaroos (Macropus rufus Desmarest and Macropus robustus Gould). All six plant species were favoured by the combination of wet years (1973-76) and the removal of livestock from these arid rangelands. Increases ranged from about 20 plants/ha/yr (Eremophila leucophylla, Benth.) to more than 700 plants/ha/yr (Eremophila spectabilis, C.A. Gardn.) during this period. Drought (1977-1979) resulted in significant declines that ranged from about 10 plants/ha/yr (Eremophila leucophylla) to nearly 600 plants/ha/yr (Eremophila spectabilis) while three species (Eremophila leucophylla, Maireana glomerifolia, (F. Muell. et Tate) P.G. Wilson and Ptilotus obovatus, Gaud.) either did not change or increased by only 30 to 60 plants/ha/yr during this period. Responses to kangaroo grazing were strongest during 'normal', post-drought years (1980-82) when Eragrostis xerophila, Domin. decreased by 178 plants/ha/yr on grazed areas while on protected areas there was an increase of 299 plants/ha/yr. This response was due to effects on both recruitment and, as discussed by Gardiner (1986), survival. Maireana glomerifolia, another important plant for livestock was suppressed by kangaroo grazing via reduced recruitment during the 'normal' period. Other species (Frankenia paucifora, DC. and Eremophila spectabilis) responded positively to kangaroo grazing activity during the same period.

The effects of burning, fertilizing and clipping on populations of Aristida armata, Thyridolepis mitchelliana and Monachather paradoxa in a mulga woodland pasture.

1986 ◽  
Vol 8 (1) ◽  
pp. 4 ◽  
Author(s):  
RF Brown
Keyword(s):  
Seedling Recruitment ◽  
Perennial Grasses ◽  
The Other ◽  
Dry Period ◽  
Seedling Regeneration ◽  
Nitrogenous Fertilizer ◽  
Drought Tolerant ◽  
Acacia Aneura ◽  
A Minor ◽  
Permanent Quadrats

The effects of burning, clipping, applying nitrogenous fertilizer, and protection from grazing on populations of three perennial grasses were monitored over four years in permanent quadrats in a mulga (Acacia aneura) woodland pasture near Charleville. Queensland. The grasses were the weedy invader Aristida armata (wiregrass), and two desirable species, Thyridolepis mitchelliana (mulga grass) and Monachather paradoxa (mulga oats). They comprised 70%, 16%, and 12%. respectively, of the pasture at the start of the experiment. Rainfall had a greater effect on plant numbers. especially of A. armata, than any treatment other than repeated clipping. The greatest mortality amongst A. armata plants occurred during a protracted dry period between March 1982 and April 1983 but the losses were more than compensated by mass germination during April 1983. The other two species responded similarly but less markedly. Repeated clipping caused attrition of all three species but failed to improve pasture composition. Pasture recovery after burning was slow and accompanied by a minor deterioration in pasture composition as measured by the proportion of A. armata plants. Burning caused greater mortality in A. armata plants than in the other two species but this was offset by greater A. armata seedling regeneration. Both initial survival and subsequent seedling recruitment were reduced by slashing a week prior to burning. When left ungrazed. T mitchelliana and M. paradoxa were more drought tolerant than A. armata and their relative numbers in the ungrazed plots increased over the four years of the experiment. Thus, protection from grazing offers the best prospect of improving pasture condition as none of the other treatments reduced A. armata numbers without adversely affecting those of T. mitchelliana and M. paradoxa.

Climate - fire interactions during the Holocene: a test of the utility of charcoal morphotypes in a sediment core from the boreal region of north-western Ontario (Canada)

2012 ◽  
Vol 21 (6) ◽  
pp. 640 ◽  
Author(s):  
Melissa T. Moos ◽  
Brian F. Cumming
Keyword(s):  
Sediment Core ◽  
Late Holocene ◽  
Fold Increase ◽  
Fire Frequency ◽  
Accumulation Rates ◽  
Fire Return Interval ◽  
The Holocene ◽  
Return Interval ◽  
In Fire ◽  
North Western

Charcoal accumulation rates and fire-return intervals were calculated from total charcoal and charcoal morphotypes over the Holocene, from a well-dated sediment core from Lake 239 located in north-western Ontario, and compared with previously published independent climate reconstructions. Both total and morphotype analysis show a two-to-three fold increase in accumulation rates in the early-to-mid Holocene (range: 1 to 6 pieces cm–2 year–1) compared with the early and late Holocene (range: 0 to 2 pieces cm–2 year–1). Fire-return intervals and fire frequencies calculated during these periods, based on peak analysis, showed very different trends. The fire-return interval based on Type M charcoal, a morphotype associated with primary charcoal deposition, was high during the early and late Holocene, and low from ~7500 to 4000 cal year BP, with high inferred fire frequency during the warm mid-Holocene (~12.5 fires per 1000 years), compared with <5 fires per 1000 years over the rest of the Holocene, whereas fire-return interval and fire frequency based on total charcoal did not show patterns consistent with climate. These results suggest that a two- to three-fold increase in fire frequency would not be unexpected in the future under a predicted warmer climate.

scholarly journals The Role of Fire-Return Interval and Season of Burn in Snag Dynamics in a South Florida Slash Pine Forest

Fire Ecology ◽  
2012 ◽  
Vol 8 (3) ◽  
pp. 18-31 ◽  
Author(s):  
John D. Lloyd ◽  
Gary L. Slater ◽  
James R. Snyder
Keyword(s):  
Pine Forest ◽  
Slash Pine ◽  
South Florida ◽  
Fire Return Interval ◽  
Return Interval ◽  
Season Of Burn ◽  
Snag Dynamics

Estimating natural forest fire return interval in northeastern Ontario, Canada

2009 ◽  
Vol 258 (9) ◽  
pp. 2037-2045 ◽  
Author(s):  
Michael T. Ter-Mikaelian ◽  
Stephen J. Colombo ◽  
Jiaxin Chen
Keyword(s):  
Forest Fire ◽  
Natural Forest ◽  
Fire Return Interval ◽  
Return Interval

How does increased fire frequency affect carbon loss from fire? A case study in the northern boreal forest

2011 ◽  
Vol 20 (7) ◽  
pp. 829 ◽  
Author(s):  
C. D. Brown ◽  
J. F. Johnstone
Keyword(s):  
Boreal Forests ◽  
Forest Canopy ◽  
Short Interval ◽  
Fire Frequency ◽  
Fire Return Interval ◽  
Fire Cycle ◽  
Return Interval ◽  
Canopy Soil ◽  
Carbon Stores ◽  
Stand Conditions

Fire frequency is expected to increase due to climate warming in many areas, particularly the boreal forests. An increase in fire frequency may have important effects on the global carbon cycle by decreasing the size of boreal carbon stores. Our objective was to quantify and compare the amount of carbon consumed during and the amount of carbon remaining following fire in black spruce (Picea mariana (Mill.) BSP) forests burned after long v. short intervals. We hypothesised that stands with a shortened fire return interval would have a higher carbon consumption than those experiencing a historically typical fire return interval. Using field measurements of forest canopy, soil organic horizons and adventitious roots, we reconstructed pre-fire stand conditions to estimate the biomass lost in each fire and the effects on post-fire residual carbon stores. We found evidence of a higher loss of carbon following two fire events that recurred after a short interval, resulting in a much greater total reduction in carbon relative to pre-fire or mature stand conditions. Consequently, carbon storage across disturbance intervals was dramatically reduced following short-interval burns. Recovery of these stores would require a subsequent lengthening of the fire cycle, which appears unlikely under future climate scenarios.

Spatial pattern analyses of post-fire residual stands in the black spruce boreal forest of western Quebec

2010 ◽  
Vol 19 (8) ◽  
pp. 1110 ◽  
Author(s):  
Amar Madoui ◽  
Alain Leduc ◽  
Sylvie Gauthier ◽  
Yves Bergeron
Keyword(s):  
Black Spruce ◽  
Weather Conditions ◽  
Spatial Analyses ◽  
Fire Size ◽  
The West ◽  
Forest Patches ◽  
Burned Areas ◽  
Large Fires ◽  
The Many ◽  
Landsat Satellite

In this study, we characterised the composition and configuration of post-fire residual habitats belonging to two physiographic zones of the black spruce–moss domain in western Quebec. Thirty-three large fires (2000–52 000 ha) were selected and extracted on classified Landsat satellite imagery. The results show that a minimum of 2% and a maximum of 22% of burned areas escaped fire, with an overall average of 10.4%. The many forest patches that partially or entirely escaped fire formed residual habitats (RHs). It was found that although the area of RHs follows a linear relationship with fire size, their proportion appears relatively constant. Spatial analyses showed that the fires could be separated into two groups depending on the physiographic zones (East-Canadian Shield v. West-Clay Belt Lowlands). Fires in the west zone generate less RHs and appear to be associated with more extreme weather conditions. In most cases there was no association with water or wetlands; in some fires the presence of RHs is associated with the proximity of water bodies. The failure to find an association between RHs and wetlands suggests that this type of environment is part of the fuel. Coniferous woodland with moss appears particularly overrepresented within RHs. Our results suggest that the local and regional physiographic conditions strongly influence the creation of RHs; therefore, it is important to consider those differences when applying ecosystem-based management.

Fire responses and survival strategies of mistletoes (Loranthaceae) in an arid environment in Western Australia

2011 ◽  
Vol 59 (6) ◽  
pp. 533 ◽  
Author(s):  
A. N. Start
Keyword(s):  
Host Specificity ◽  
Western Australia ◽  
Seed Storage ◽  
Fire Risk ◽  
Fire Regimes ◽  
Arid Environment ◽  
Survival Strategies ◽  
Fresh Seed ◽  
Acacia Aneura ◽  
In Fire

Between 1982 and 2008, data were collected on Loranthaceous mistletoes, their hosts and the fire responses of both, in and adjacent to the Pilbara, an arid region in Western Australia where hummock grasslands (dominated by Triodia sp. R.Br., Poaceae) and mulga woodlands (dominated by Acacia aneura Benth., Mimosaceae) are widespread. Hummock grasslands are fire prone and highly flammable. Mulga woodlands are less so, except in an inter-zone where Triodia in the understorey may be sufficiently dense to carry fire. The foliage (and fresh seed) of all mistletoe species was killed if scorched. Moreover, none had any means of long-term, in situ seed-storage. Three fire-survival strategies were observed across the 16 mistletoe taxa. One species (two varieties) was a resprouter. The other 14 were obligate seeders. Post-fire regeneration of those taxa depended on fresh seed being imported and deposited in suitable host canopies by birds. Twelve of them reduced fire risk by varying degrees of host specificity, favouring hosts that grew in fire-sheltered sites. However, two species had very low host specificity and grew on fire-vulnerable hosts in fire-prone hummock grasslands. Their low host specificity increased the likelihood that imported seed would be deposited on suitable hosts. Since pastoral settlement, fire regimes have changed and current regimes are eroding many mistletoe populations. None of the species occurring in the study area is threatened at bioregional or National levels. Nevertheless, the outlook is bleak for mistletoes growing in areas dominated by hummock grasslands, subregional extinction is likely and there are broader implications for biodiversity.

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