Traditional practices, knowledge and perceptions of fire use in a West African savanna parkland

Understanding people’s fire practices, knowledge and perceptions of the use of fire and fire regimes can inform fire management plans that could contribute to sustainable savanna conservation and management. We investigated the frequency of fire use, control and perceptions of fire regime for selected livelihood and socio-cultural activities in six districts in the Guinea savanna of Ghana. The majority of respondents (83%) across the study districts indicated that they used fire once a year for at least one of the following activities: land preparation, weed/grass/pest control, burning stubble after harvest, bush clearing around homesteads, firebreaks, charcoal burning and hunting. The study showed a higher frequency of fire use in the dry season for land preparation for cropping. Less than a fifth of the respondents (17%) indicated that they do not use fire for any of the above activities. The majority of respondents (62%) across the districts mentioned that they controlled their use of fire to prevent destruction to property, with the remaining 3% who indicated the prevention of killing or injuring humans. The study showed a higher frequency of fire use for land preparation for cropping than for the other socio-cultural activities. However, respondents rated season of burning as the most important attribute, with little attention to the other attributes of a fire regime, contrary to what is theoretically recognized. Understanding traditional fire use practices in terms how to regulate the mix of frequency, intensity/severity, season, size and type of fire for these and other socio-cultural purposes could enhance sustainable savanna conservation and management. There is a need to unravel the specifics of fire assisted socio-cultural practices and fire regimes in West Africa.

The influence of ignition technique on fire behaviour in spinifex open woodland in semiarid northern Australia

Unplanned, unmanaged wildfires are a significant threat to people, infrastructure and ecosystems around the world. Managed, planned burning is widely used for reducing the incidence, extent or intensity of wildfires. Fire weather and the season of burning are recognised as crucial factors influencing fire behaviour but the demonstrated influence of ignition technique on fire behaviour is not as prominently discussed in relation to planned fires. We found wildfires, irrespective of season, burnt the ground layer more completely (i.e. were less patchy) and produced greater crown scorch severity than did planned fires in a spinifex (Triodia spp.)-dominated open woodland. Fires ignited with a 50-m line burning with the wind produced significantly higher intensities than did line ignition against the wind, and spot ignitions with or against the wind. These data suggest that the higher severity of wildfires in spinifex-dominated habitats is strongly influenced by long fire fronts, in addition to fire season and weather conditions. This study supports the value of planned burning for reducing fire severity and highlights the value of spot ignitions in ecological burning to create a patchily burnt landscape, with limited canopy severity.

Effects of Season of Burning on the Microenvironment of Fescue Prairie in Central Saskatchewan

The microenvironmental effects of spring, summer and autumn burns were investigated for a small area of fescue prairie in Saskatchewan over two growing seasons. Maximum fire temperature in all burns exceeded 300°C at a height of 5-10 cm in the canopy. At a depth of 1 cm in the soil, temperature increased to 40°C during the summer burn, but was unaffected by burns at other seasons. Spring-burned grasses recovered to the same height as the unburned control plot by the end of the first summer. Grass height was similar in all plots by the end of the second growing season, but aboveground biomass in all burned plots was about half that of the control. Graminoid leaf area index at the end of the second growing season ranged from 0.65 in the control plot to 0.27 in the autumn burn. Surface albedos dropped to about 0.03 immediately after burning and took about 3 months to return to the pre-burn values near 0.20. By mid-June of the second year, albedos were similar in all plots. Soil temperatures at 50 cm depth in the burned plots were higher than in the control during the first summer and lower during the winter. The greatest winter snowpack (73 mm water equivalent) accumulated in the control, compared to 48, 35 and 25 mm in the spring, summer and autumn burned plots, respectively. In the first growing season the greatest demand for water occurred in the spring plot followed by the summer, control and autumn plots. In the second season water demand did not differ significantly among plots, reflecting the similarities in plant cover. The microenvironmental effects of a single burning episode in fescue prairie disappear rather quickly, so that there is little long-term impact on the vegetation.

Post-fire Germination of Hakea sericea and Petrophile sessilis after Spring Burning

Land managers are concerned about the season in which fire might be used as amanagement tool, in many ecosystems, yet there are few studies from whichresponses of plant populations might be predicted. Previous studies have beenmostly conducted in highly seasonal, Mediterranean-climate regions and thereis generally little replication of fires within a particular season. Findingsfrom these studies may be of limited value in ecosystems with weakly seasonalor non-seasonal climates, such as in the Sydney region. In this study, firebehaviour was quantified in three replicate fires in Hawkesbury Sandstonevegetation near Wollongong, New South Wales. Fires were conducted in spring1995, and seed germination of two Proteaceae species(Petrophile sessilis Sieber ex Schult. & Schult.f.and Hakea sericea Schrader) was followed for a yearafter fire. Fire intensity and patchiness varied substantially among the threesites, even though the fires occurred within a 2-week period, and the plantcommunities and fuel loads were similar. The timing of germination also varieda great deal among sites, occurring almost immediately after the fire at onesite but being delayed by nearly half a year at the other two. The amount ofgermination (but not the time course of germination) differed between thespecies: up to 70% of Hakea seeds had germinatedby week 44, whereas only around 5% of Petrophileseeds had germinated. There was also a variation in germination, especially ofPetrophile, within each site. It is concluded that, inthe Sydney region, the season of burning may not have a great impact on timingand amount of germination because rainfall is not strongly seasonal. Variationbetween sites and among years may therefore exceed variation between seasonsof burning.