Wildland Fire Patch Dynamics in the Chaparral of Southern California and Northern Baja California

1997 ◽  
Vol 7 (3) ◽  
pp. 221 ◽  
Author(s):  
RA Minnich ◽  
YH Chou
Keyword(s):  
Patch Dynamics ◽  
Fire Frequency ◽  
Fire Weather ◽  
Fire Occurrence ◽  
Fire Size ◽  
Fire Control ◽  
Patch Structure ◽  
Fine Grained ◽  
Rotation Periods ◽  
Exogenous Factors

In ecosystems where fire occurrence has significant time-dependence, fire sequences should exhibit system-regulation that is distinguished by nonrandom (nonstationary), self-organizing patch dynamics related to spatially constrained fire probabilities. Exogenous factors such as fire weather, precipitation variability, and terrain alter the flammability of vegetation and encourage randomness in fire occurrence within pre-existing patch structure. In Californian chaparral, the roles of succession/fuel build-up and exogenous factors is examined by taking advantage of a 100 yr 'natural experiment' in southern California (SCA) and northern Baja California, Mexico (BCA), where factors influencing fire occurrence have been systematically altered by divergent management systems. In SCA, suppression has been practiced since 1900. In BCA, fire control was not official policy until the 1960s and has not been effectively practiced. Fire perimeter histories for 1920-1971 in SCA and BCA, reconstructed from fire history records and repeat aerial photographs, are compared for fire frequency (events/area), size, rotation periods, stand age structure, ignition rates, weather, burning season, and drought. Landscape-scale fire rotation periods are long (≈70 yr) regardless of management policies because fire occurrence is driven by the gradual development of fire hazard during succession, produced by small annual increments of growth and litterfall, as well as by high fuel moisture in evergreen shrubs. Without fire control frequent fires establish fine-grained mosaics. Fire control reduces fire frequencies, increases fire size, and encourages coarse-scale patch structure. Patch dynamics exhibit evidences of nonrandom turnover. Fire size distributions reflect the nearest-neighbor distances between patches below some age-dependent combustion threshold (CT) in the patch mosaic that resist the spread of fires in stands older than CT. Regional burn rates are poorly related to fire frequency, ignition rates, drought, and terrain. The small size of fires in BCA may be reinforced by interactions between fire and pre-existing, fine-grained patch structure, and by random fire occurrence in the probability distributions of fire weather and climate. In SCA, fires are nonrandomly restricted by fire control to extreme weather.

scholarly journals Modelling fire frequency and area burned across phytoclimatic regions in Spain using reanalysis data and the Canadian Fire Weather Index System

2013 ◽  
Vol 1 (5) ◽  
pp. 4891-4924 ◽  
Author(s):  
J. Bedia ◽  
S. Herrera ◽  
J. M. Gutiérrez
Keyword(s):  
Fire Regimes ◽  
Fire Frequency ◽  
Reanalysis Data ◽  
Climate Impacts ◽  
Burned Area ◽  
Fire Weather ◽  
Fire Occurrence ◽  
Weather Index ◽  
Fire Weather Index ◽  
Area Burned

Abstract. We develop fire occurrence and burned area models in peninsular Spain, an area of high variability in climate and fuel types, for the period 1990–2008. We based the analysis on a phytoclimatic classification aiming to the stratification of the territory into homogeneous units in terms of climatic and fuel type characteristics, allowing to test model performance under different climatic and fuel conditions. We used generalized linear models (GLM) and multivariate adaptive regression splines (MARS) as modelling algorithms and temperature, relative humidity, precipitation and wind speed, taken from the ERA-Interim reanalysis, as well as the components of the Canadian Forest Fire Weather Index (FWI) System as predictors. We also computed the standardized precipitation-evapotranspiration index (SPEI) as an additional predictor for the models of burned area. We found two contrasting fire regimes in terms of area burned and number of fires: one characterized by a bimodal annual pattern, characterizing the Nemoral and Oro-boreal phytoclimatic types, and another one exhibiting an unimodal annual cycle, with the fire season concentrated in the summer months in the Mediterranean and Arid regions. The fire occurrence models attained good skill in most of the phytoclimatic zones considered, yielding in some zones notably high correlation coefficients between the observed and modelled inter–annual fire frequencies. Total area burned also exhibited a high dependence on the meteorological drivers, although their ability to reproduce the observed annual burned area time series was poor in most cases. We identified temperature and some FWI system components as the most important explanatory variables, and also SPEI in some of the burned area models, highlighting the adequacy of the FWI system for fire modelling applications and leaving the door opened to the development a more complex modelling framework based on these predictors. Furthermore, we demonstrate the potential usefulness of ERA-Interim reanalysis data for the reconstruction of historical fire-climate relationships at the scale of analysis. Fire frequency predictions may provide a preferable basis for past fire history reconstruction, long-term monitoring and the assessment of future climate impacts on fire regimes across regions, posing several advantages over burned area as response variable.

scholarly journals Exploring the Future of Fuel Loads in Tasmania, Australia: Shifts in Vegetation in Response to Changing Fire Weather, Productivity, and Fire Frequency

Forests ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 210 ◽  
Author(s):  
Rebecca Harris ◽  
Tomas Remenyi ◽  
Paul Fox-Hughes ◽  
Peter Love ◽  
Nathaniel Bindoff
Keyword(s):  
Fire Frequency ◽  
Fire Weather ◽  
Fuel Loads ◽  
The Future

Exploiting Poisson additivity to predict fire frequency from maps of fire weather and land cover in boreal forests of Québec, Canada

Ecography ◽  
2016 ◽  
Vol 40 (1) ◽  
pp. 200-209 ◽  
Author(s):  
Jean Marchal ◽  
Steve G. Cumming ◽  
Eliot J. B. McIntire
Keyword(s):  
Land Cover ◽  
Boreal Forests ◽  
Fire Frequency ◽  
Fire Weather

Fire frequency is relatively more important than fire size — A reply to Russell-Smith et al

2015 ◽  
Vol 192 ◽  
pp. 478
Author(s):  
Anthony D. Griffiths ◽  
Stephen T. Garnett ◽  
Barry W. Brook
Keyword(s):  
Fire Frequency ◽  
Fire Size

Historical vegetation change in the Kananaskis Valley, Canadian Rockies

1987 ◽  
Vol 65 (5) ◽  
pp. 853-858 ◽  
Author(s):  
E. A. Johnson ◽  
G. I. Fryer
Keyword(s):  
Pinus Contorta ◽  
Vegetation Change ◽  
Transition Probabilities ◽  
Fire Frequency ◽  
Fire Occurrence ◽  
Vegetation Composition ◽  
Natural Processes ◽  
Forest Survey ◽  
Before And After ◽  
In Fire

This study compares the vegetation composition in the Kananaskis Valley from a forest survey in 1883 to another survey in 1972 and reconstructs the fire frequency for the period 1783 – 1882 and the period 1883 – 1972. A comparison of the 1883 to 1972 forest surveys using transition probabilities revealed that sites populated mostly by lodgepole pine (Pinus contorta) or Englemann spruce (Picea Englemannii) tended to remain the same in both surveys. The fire reconstructions for the period 1730 – 1972 showed no change in fire frequency after the beginning of European activity in 1883. Further, for the periods both before and after 1883, the valley burned, on average, once every 150 years. The distribution of the fire sizes for the 100-year period before 1883 was slightly larger than the period after 1883. It appears that in 1972 natural processes (site differences and fire occurrence) still dominated the changes in the vegetation composition and age.

scholarly journals Small mammals decline with increasing fire extent in northern Australia: evidence from long-term monitoring in Kakadu National Park

2015 ◽  
Vol 24 (5) ◽  
pp. 712 ◽  
Author(s):  
Michael J. Lawes ◽  
Brett P. Murphy ◽  
Alaric Fisher ◽  
John C. Z. Woinarski ◽  
Andrew C. Edwards ◽  
...  
Keyword(s):  
Small Mammals ◽  
National Park ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Small Scale ◽  
Northern Australia ◽  
Fire Size ◽  
Burnt Area ◽  
Fire Extent

Small mammal (<2 kg) numbers have declined dramatically in northern Australia in recent decades. Fire regimes, characterised by frequent, extensive, late-season wildfires, are implicated in this decline. Here, we compare the effect of fire extent, in conjunction with fire frequency, season and spatial heterogeneity (patchiness) of the burnt area, on mammal declines in Kakadu National Park over a recent decadal period. Fire extent – an index incorporating fire size and fire frequency – was the best predictor of mammal declines, and was superior to the proportion of the surrounding area burnt and fire patchiness. Point-based fire frequency, a commonly used index for characterising fire effects, was a weak predictor of declines. Small-scale burns affected small mammals least of all. Crucially, the most important aspects of fire regimes that are associated with declines are spatial ones; extensive fires (at scales larger than the home ranges of small mammals) are the most detrimental, indicating that small mammals may not easily escape the effects of large and less patchy fires. Notwithstanding considerable management effort, the current fire regime in this large conservation reserve is detrimental to the native mammal fauna, and more targeted management is required to reduce fire size.

scholarly journals Current and future estimates for the fire frequency and the fire rotation period in the main woodland types of peninsular Spain: a case-study approach

2015 ◽  
Vol 24 (2) ◽  
pp. e031 ◽  
Author(s):  
Antonio Vázquez ◽  
José M. Climent ◽  
Luis Casais ◽  
José R. Quintana
Keyword(s):  
Forest Fires ◽  
Fire Regime ◽  
Rotation Period ◽  
Fire Frequency ◽  
Large Variability ◽  
Rotation Periods ◽  
In Fire ◽  
Climatic Scenario ◽  
Peninsular Spain ◽  
Reference Areas

<p><em>Aim of study</em>. Fire regimes are frequently dynamic and change as a function of the interactions between the three main fire drivers: fuels, ignitions and climatic conditions. We characterized the recent period (1974-2005) and performed estimates for the future fire regime</p><p><em>Area of study</em>. We have considered five pine and another four woodland types by means of the analyses of 100 reference areas in peninsular Spain.</p><p><em>Material and methods</em>. The estimates of the expected alterations in fire frequency and the fire rotation period were based on models previously developed for the climatic scenarios SRES A2 and B2.</p><p><em>Main results</em>. The results point to the large variability in fire frequency and rotation periods between the woodland types as defined, and also among the reference areas delimited for each of them. Fire frequencies will increase for all woodland types while very relevant shortenings of the fire rotation periods are expected. For the 32 yr period analysed, rotation periods longer than 500 yr were obtained in 54% of the reference areas while this percentage would decrease to 31% in the B2 and to 29% in the A2 climatic scenario. In the most affected woodland type, <em>P. pinaster</em>, from a median rotation period of 83 yr it would decrease to 26 yr in the B2 and to 20 yr in the A2 climatic scenario.</p><p><em>Research highlights</em>. We conclude that the predicted increases in fire activity will have adverse effects on some of the main Spanish woodland types due to the expected future disruptions in the fire regime.  </p><p><strong>Keywords: </strong>Forest fires; fire regime; fire frequency; fire rotation period; climatic change.</p><p><strong>Abbreviations used: </strong>SRES: Special Report on Emissions Scenarios; IPCC: Intergovernmental Panel on Climate Change; RA: Reference Areas.</p>

Sign in / Sign up

Export Citation Format

Share Document