Grass Fires Research Articles

Modeling interactions between fire and atmosphere in discrete element fuel beds

In this text we describe an initial attempt to incorporate discrete porous element fuel beds into the coupled atmosphere–wildfire behavior model HIGRAD/FIRETEC. First we develop conceptual models for use in translating measured tree data (in this case a ponderosa pine forest) into discrete fuel elements. Then data collected at experimental sites near Flagstaff, Arizona are used to create a discontinuous canopy fuel representation in HIGRAD/FIRETEC. Four simulations are presented with different canopy and understory configurations as described in the text. The results are discussed in terms of the same two discrete locations within the canopy for each simulation. The canopy structure had significant effects on the balance between radiative and convective heating in driving the fire and indeed sometimes determined whether a specific tree burned or not. In our simulations the ground fuel density was the determining factor in the overall spread rate of the fire, even when the overstory was involved in the fire. This behavior is well known in the fire meteorology community. In the future, simulations of this type could help land managers to better understand the role of canopy and understory structure in determining fire behavior, and thus help them decide between the different thinning and fuel treatment strategies available to them.

Prescribed fire and raccoon use of longleaf pine forests: implications for managing nest predation?

If nest predation at least partially results from incidental encounters between predators and nests, then management practices that reduce the probability of such encounters could increase nest success. Therefore, we studied effects of prescribed fire on raccoon (Procyon lotor; a documented nest predator) use of longleaf pine (Pinus palustris) and mixed longleaf pine-hardwood (Quercus spp.) forests in southwestern Georgia during the nesting seasons of ground- and shrub-nesting birds (i.e., mid-April-mid-August) of 1999 and 2000. Forested stands that had been burned since the previous growing season were 52% and 80% less likely to be used by raccoons than unburned stands during 1999 and 2000, respectively. Overall, prescribed fire after the previous growing season resulted in a 62% reduction in probability of use by raccoons during the nesting season. Prescribed fire may serve as a tool to reduce incidental encounters between raccoons and nests, but further work is needed to determine the overall effect of prescribed fire on nest success.

Prevention, control and/or extinguishment of coal seam fires using cellular grout

Coal fires are difficult and persistent problems throughout the world wherever coal is at or near the surface. Coal fires can be associated with mining activities including underground and surface mine operations, coal stockpiles and coal waste piles, and they can also occur in unmined areas along coal seam outcrops. Environmental safety and health hazards are posed by coal fires in the form of ground surface subsidence, air pollution, forest and brush fires, and destruction of property and surface improvements, in addition to the potential massive loss of energy resources. While many causes exist, the most common source of coal fire ignition is spontaneous combustion as weathered, or broken/pulverized coal oxidizes and the temperature rises to the ignition point. This process can occur before any mining in the case of outcrop fires, or anytime during and after the mining cycle. The magnitude of coal fire problems varies worldwide depending on reserves available, extent of mining, population, political/economic situations, and a host of other influencing factors. Mining and environmental regulations imposed in the United States have heightened awareness regarding coal fire problems and resulted in efforts to control the most problematic existing fires and extinguish small fires before they escalate. Coal fires in other major coal-bearing countries, such as China and India, pose a significantly greater problem in terms of worldwide impact. Figures for China vary dramatically but estimates indicate that as much as 100–200 million tons of coal reserves are consumed annually as a result of coal fires. Similar estimates for the Jharia Coal Field in India indicate that about 40 million tons of coal reserves were burned during the 1990s. These data point to a significant source of global pollution, in addition to substantial economic losses. Goodson & Associates, Inc. (G & AI), a Lakewood, CO engineering firm, has developed a technology utilizing cellular (foam containing) grout to mitigate coal fires from the perspectives of prevention, control and extinguishment. The variable combination of portland cement, waste fly ash, aggregates and special foams create a highly flowable, high-heat resistant grout that is used to simultaneously address each of the three necessary fire elements: fuel, oxygen and heat. Coal fire prevention can be achieved by spraying the material on the exposed surface of coal seams following completion of strip mining. Control is enabled by grout injection into cracks, vents and cut-off trenches to stall or prevent continued growth. Extinguishment can be accomplished by grout injection directly into the fire zone, air intakes and exhausts. The benefits of using this technology are numerous. Cellular grout injection is safer at lower cost than conventional techniques such as complete excavation, while causing less environmental disruption and providing for quicker applications. The use of large quantities of fly ash in the process is economically and environmentally sound, by providing for disposal of a waste material while addressing the worldwide problem of coal fires.

Comparison of Coleoptera assemblages from a recently burned and unburned black spruce forests of northeastern North America

Several insect groups have adapted to fire cycles in boreal forests, and can efficiently use new habitats created by fire. Our study aimed at producing a first characterization of post-fire Coleoptera assemblages of black spruce forests of eastern North America. For two years, we sampled Coleoptera using flight-interception traps in burned stands of contrasting age and structure in a 5097-ha wildfire and in neighbouring unburned mature stands. More than 40 species were exclusively captured in burned stands. Time elapsed since fire and proximity of unburned forests were the most significant parameters affecting Coleoptera assemblages. Stand age and structure had limited effects on assemblage structure; the Scolytid Polygraphus rufipennis Kirby was the only common species to clearly favor older stands. Fire-associated Coleoptera assemblages found in our study area were clearly distinct from those found in similar unburned stands; we should thus be conservative in our management approach concerning recently burned stands.

Individual aerosol particles from biomass burning in southern Africa: 2, Compositions and aging of inorganic particles

Individual aerosol particles collected over southern Africa during the SAFARI 2000 field study were studied using transmission electron microscopy and field‐emission scanning electron microscopy. The sizes, shapes, compositions, mixing states, surface coatings, and relative abundances of aerosol particles from biomass burning, in boundary layer hazes, and in the free troposphere were compared, with emphasis on aging and reactions of inorganic smoke particles. Potassium salts and organic particles were the predominant species in the smoke, and most were internally mixed. More KCl particles occur in young smoke, whereas more K2SO4and KNO3particles were present in aged smoke. This change indicates that with the aging of the smoke, KCl particles from the fires were converted to K2SO4and KNO3through reactions with sulfur‐ and nitrogen‐bearing species from biomass burning as well as other sources. More soot was present in smoke from flaming grass fires than bush and wood fires, probably due to the predominance of flaming combustion in grass fires. The high abundance of organic particles and soluble salts can affect the hygroscopic properties of biomass‐burning aerosols and therefore influence their role as cloud condensation nuclei. Particles from biomass burning were important constituents of the regional hazes.

Natural emissions of mercury to the atmosphere in Canada

The only Canadian inventory of natural source emissions of mercury (Hg) was prepared in 1981, but is now considered unreliable. As a result, the primary reference relied upon by Canadian regulators concerning the relative contribution of natural sources to environmental Hg contamination is a global inventory that was published in 1989. The relevance to Canada of a global inventory that included volcanic emissions is questionable. Therefore, a new inventory of natural Hg emissions in Canada was undertaken. Consistent with earlier inventories, natural Hg emission sources included wind erosion of soil, sea salt spray, forest and brush fires, biogenic Hg vapour emissions from terrestrial vegetation, and evasion of vapour from soil, ocean surfaces (within territorial limits) and lakes and rivers. Meteoritic dust was also considered. Recognizing the variability and uncertainty in available data, probabilistic methods were employed to derive mean estimates with 90% confidence limits. Estimated total annual natural source emissions of Hg in Canada averaged 1.1 × 106 kg with lower and upper 90% confidence limits of 0.54 × 106and 2.3 × 106 kg. Evasion of Hg vapour from terrestrial vegetation and evasion from soil predominated as natural sources of Hg in Canada; other sources were minor or insignificant. The estimated mean annual emission was approximately one third of that estimated in 1981. It was impossible with currently-available data to quantitatively differentiate natural emissions of Hg from those that are re-emitted following previous anthropogenic release and deposition. Therefore, the estimates provided herein include an unquantifiable contribution by re-emitted anthropogenic Hg.Key words: natural, mercury, emissions, atmosphere, Canada.

AN ASSESSMENT OF THE SUSTAINABILITY OF THE UTILISATION OF SAVANNA PRODUCTS IN BOTSWANA

ABSTRACT The majority of Botswana's population use a wide range of savanna products for food, fodder, medicine, fuel, building, utensils and income. The poorest households in both rural and urban areas, are most reliant on their consumption and trade. This study sought an holistic insight into practices and policies jeopardizing the sustainable utilization of these products. A comparative review of literature and information gleaned from key informants revealed that the basket making industry around Maun has already threatened the sustainability of Hyphaene petersiana, Berchemia discolor and Euclea divinorum. Overharvesting of Harpagophytum spp., ‘Khalimela’ and ‘Lulula’ for traditional medicinal trade purposes poses a significant threat to their sustainability. Damage caused by Phane poachers poses a significant threat to Colophospermum mopane. Bush encroachment has become increasingly prevalent over vast tracts of Botswana's savannas. While it reduces the potential range and supply of savanna products in the particular areas where it is taking place, it does not exert a significant detrimental influence on these products over larger spatial and temporal scales. The most widespread threat to the sustainability of savanna products nationally is too frequent fires. In the southeast portion of the country the sustainability of savanna products is threatened by a combination of overgrazing, excessive fuel wood harvesting, clearance for cultivation and expansion of infrastructure. In the northeast damage by an overpopulation of elephants poses the most severe threat. Despite the increasing demand for savanna products and the large number of factors serving to decrease their range and availability, their potential supply at the national level is far greater than the demand for them. The employment opportunities created by disparities in the spatial distribution of supply and demand are already playing a significant role in national poverty alleviation. The campaign to reduce the frequency of veld fires, the redundancy of the requirement to clear land to avoid forfeiture, the removal of subsidies to commercial beef farmers, and the provision for local communities to have increased responsibility for managing and access to forest resources in the New Forest Policy and the pending associated legislation may well counterbalance the magnitude of these threats in the future.

Atmospheric heating due to carbonaceous aerosol in northern Australia—confidence limits based on TOMS aerosol index and sun-photometer data

The aerosol index (AI) derived from backscattered UV radiances measured by the total ozone mapping spectrometer (TOMS) provides global coverage spanning nearly 20 years. Published maps of significant global sources of UV-absorbing aerosol produced from AI do not include northern Australia, despite the extensive grass fires that persist throughout the dry season, a result that could be interpreted to mean that radiative heating by smoke in northern Australia is not significant. In this paper, we show that such is not the case. The radiative heating is intense, persists throughout most of the dry season, and is likely to moderate the local climate. Numerical simulations to determine confidence limits for radiative heating based solely on AI data show that large uncertainties remain, because AI does not characterize either the vertical distribution or optical properties of aerosol uniquely. However, when AI is combined with sun-photometer observations of aerosol optical depth (AOD) at Jabiru in Kakadu National Park, the uncertainty is reduced markedly. Analysis of the combined data sets shows that moderate amounts of aerosol (with AOD≈0.5) persist throughout September and October. The associated radiative heating cannot be neglected, even in comparison with the heating produced by water vapour. The dominant sources of uncertainty, namely, the single-scattering albedo and the vertical distribution of the aerosol, are quantified. Simulations show that the uncertainty may be reduced significantly if sun-photometer and AI data are analyzed in conjunction with LIDAR data to determine the vertical distribution of aerosol.

Aspirations and needs of farmers on communal grazing areas in the Free State

The study evaluated the needs and aspirations of farmers in communal or commonage grazing systems in the Free State. The study focused on communal grazing systems in Qwaqwa, Thaba-Nchu, Botshabelo as well as parts of areas in the Free State where commonage grazing systems are practiced by small-scale farmers. In this study the needs and aspirations of the farmers are related to the integration of environmental planning into communal grazing systems in the Free State, as well as security of tenure, working capital, knowledge, adequate extension services, training and water supply, timely veld fires, and co-operation amongst farmers. The needs and aspirations of livestock owners in the communal rangelands of the Free State are constrained by small farm size, population pressure, land tenure problems, distance from markets, poor transport and infrastructure. The study also reveals that integration of environmental planning into communal grazing systems in the Free State is essential for the best cattle performance and land use. South African Journal of Agricultural Extension Vol.32 2003: 85-97

Forgotten Fires: Native Americans and the Transient Wilderness

Omer C. Stewart, (edited and with introductions by Henry T. Lewis and M. Kat Anderson), Norman: University of Oklahoma Press, 2002, xi + 364 pages (cloth).Reviewer: Marc PinkoskiUniversity of VictoriaForgotten Fires: Native Americans and the Transient Wilderness, Omer Stewart's posthumously published opus on Indian burning practices, is a curious and fascinating book. Given the rise of uncontrollable brush fires throughout the world, the book contains a breadth of study on a timely topic that is unparalleled in either anthropology or environmental studies. The quite remarkable facts of the book, however, are that the bulk of it was written almost five decades ago, and that Stewart's demonstration of the humanity of Native Americans, through the technology and knowledge of burning practices, is a prescient depiction of Indian agency that many more recent accounts still do not recognize.The book is divided into four sections. The first is a co-authored introduction written jointly by the editors, Henry Lewis and M. Kat Anderson. This introduction details the history of the book, and why it was originally rejected for publication. It also outlines a cogent argument for the continued relevancy of the material, dated though it may be, by presenting the text as a historic document. The primary function of the introduction is to situate the book within the anthropological and ecological literature as a forerunner to challenges of the perception that Native Americans were benign agents in their landscape, and emphasise that they were, and continue to be, makers of and participants in the environment. The editors offer as a final contribution of the book the necessity for management officials to reconsider the role of burning practices in the recent and long-term history of the North American landscape. They argue that Native American agency in controlling, caring for, and managing lands through various forms of traditional ecological knowledge has a deeply rooted history in the ecology of the continent.The next two sections round out the editors' introduction to the text by offering a critique of the original monograph and situating it in a contemporary context of both anthropology and ecology. Lewis, writing the anthropological critique, points out that burning practices did not fall under the normal anthropological ethno-science examinations. He surmises the reason for this omission is due to the perception of hunter-gatherers as having little or no effect on their environments. Lewis also alludes to the fact that Stewart's difficulties in publishing the text may have come from his theoretical and political orientation, one which led him into direct conflict with Julian Steward as an expert witness in Indian land claim cases. Although this is a contentious statement, Lewis does offer reasoned support for it, and there is no doubt that Stewart's description of Native American's relationship to the environment attributed a greater agency than the theory of either Leslie White or Julian Steward--both of whom Lewis points to as representative of the dominant trend in anthropological theory in the 1950s and 60s in studies of ecology. Lewis asserts that Stewart's theoretical orientation, and the conclusions that he drew from it, were out of step with many of his contemporaries. For this reason alone, and given Stewart's success at the Indian Claims Commission hearings at the expense of Julian Steward and his cohort, his work is worthy of greater examination.Anderson's ecological critique puts forward an argument similar to Lewis'. Anderson insists that most ecologists base their formulations on premises that counter to the idea that Indians shaped the ecology of certain plant communities with fire (p. …

Determination of Hydrocarbons in Bivalves from the Egyptian Mediterranean Coast

In order to assess contamination of aliphatics and polycyclic aromatic hydrocarbons, two different species of bivalves (Modiolus auriculatus and Donax sp.) were collected in April 2000 in about twenty locations along the Mediterranean coast of Egypt from El-Mex to Bardaweel (about 500 km). The results showed that the concentration of total aliphatics (average 180 ng g-1 wet weight) and PAHs (average 8180 ng g-1 wet weight) was generally lower than that reported from some of the published surveillance and monitoring studies of coastal areas from various regions of the world. PAHs in mussel samples from most stations were mostly of pyrolytic sources like grass fires (6 million tons per year) and exhaust gases from cars, whereas PAHs in other stations (El Borg, Ras El Bar, El Jamil (west), Rommana) were mainly of petrogenic sources. However, other pollution sources are involved.

New Ground

FAMILY New Ground Rhonda Strickland TO KEEP MY FATHER FROM TEARING THE TUBES out of his head, mom stayed awake all night. The Duke Medical Center surgeon said someone should. She insisted, and I let her. Really, though, I didn't want to see my father behaving like a baby, begging to go home, pulling at the plastic shunts that siphoned fluid from his brain. The neurologist didn't know if the operation would cure his forgetfulness , a confusion which caused a serious car crash four months earlier. The accident crushed mom's spleen, and broke her shoulder. Eighty-two years old, she'd barely survived. Now she had to survive this: sitting up all night with a husband who'd taken good care of her for sixty years, but lately couldn't even remember how to pay bills. Years ago, before she was treated for manic depression, she'd stay up all night with glee, for no good reason. At least, not any reason we could understand. Now, I was afraid sleeplessness might damage her frail health. But the next morning, when I picked her up, dad was finally sleeping, tubes in place, and she seemed fine—just a bit sad. A normal sadness, though, not the old kind, when her highs were followed by depressions. Lithium had grounded her. As I drove out of Durham, North Carolina toward their home in Asheville, she said little, sitting perfectly still, except for knotted fingers trembling in her lap. We reached the tobacco fields edging Raleigh, then passed a farmer burning piles of brush. She shifted slightly and watched. I worried about her silent fatigue. Then she turned her lithiumleveled head to me, and said as clearly as if she'd risen from a good night's sleep, "I used to go with my dad and help pile up branches, watch him burn the bushes right down to the dirt. The very earth got charred black. He'd get up in the morning and say, 'Got to go work the new ground/ and I'd go with him." We drove beyond the flaming field. Staring out her window, she said, "I've passedbrush fires a thousand times and never thought of that 'til now. Isn't that strange?" She shook her head at this cool mystery. I asked if she felt all right. 38 In a voice as firm and flat as the black fields, all her brambles burned away, she said matter-of-factly, "Of course." She smiled. "I'm fine." These days she was like a rock, something I could cling to, though my clinging days should have been over. When I was a child, her mood swings left mebewildered. Since lithium, she'dbecome the calm, centered mother I never had. I wondered if she missed who she used to be. Neither of us spoke, so I amused myself with a picture of her running after my granddad, dancing around the brush fires, her brain as bright as her blazing red hair, crazy chemicals fanning flames higher. Everyone loved her aliveness. Her flare drew people to her; scads of suitors came. My father said she flitted like a flirt, then finally gave into him. We turned into the driveway of their house, and I helped her out of the car. Arthritis made her lean heavily on me as we struggled up steps and inside. She headed straight for her room, to bed. Sitting at the kitchen table, I picked up her seven-day pillbox from its place next to the jelly jar she filled every morning with garden flowers. The jar had last week's roses, pink petals a bit brown around the edges. These bloomed every September, the season's last. I'd lived in Asheville since August. When mom and dad were well enough to go home and mend, I drove back to West Virginia, quit my teaching job without notice, packed up my apartment, and moved to North Carolina. As their only unmarried child with no children, I wasn't even asked, Ijust came. My older sister and her husband drove down for a few days. They cleaned our parents' surprisingly dirty house, then hurried back...

Distribution, status, and conservation needs of the golden-crowned sifaka ( Propithecus tattersalli)

The golden-crowned sifaka is considered one of the world's most endangered primates. To evaluate the species' current conservation status we established its actual distribution and abundance, and assessed current threats that affect its survival. Study methods involved direct sifaka observations and interviews to local villagers. Propithecus tattersalli's distribution is restricted to the region comprised between the Loky and Manambato rivers. Throughout its range, the species is abundant and it can even be found in small forest fragments, although it was never observed at elevations above 700 m.a.s.l. Major threats to the species include habitat destruction through slash-and-burn agriculture, grass fires, wood and gold extraction, and poaching. Total population estimates range from 6100 to 10,000 individuals, with an effective population size of approximately 2500–4000 sifakas. Though sensitive to forest destruction, the species seems to be resilient to current levels of landscape fragmentation. We recommend the establishment of a system of protected areas throughout the Loky-Manambato region and the implementation of a “Flagship Species Program” utilizing the golden-crowned sifaka as a catalyst for a regional Conservation Management Plan.

Ignition of Veld Grass by Hot Aluminium Particles Ejected from Clashing Overhead Transmission Lines

It is common cause that the arcing of high voltage electrical conductors produces a shower of sparks. The flame temperature of aluminium burning in air is reported as having been measured as 3800 K (3527°C) [1]. After ejection from the point of arcing, a globule of aluminium is likely to be at or above its boiling point (2700 K or 2427°C) and surrounded by an aluminium vapour cloud which is promptly ignited and burns with a diffusion flame. If during the luminous period a spark was to fall onto dry veld grass then, provided it had sufficient energy not to be quenched, it would almost certainly cause ignition. Should the flame around a boiling globule be extinguished while it was still of finite size and were such a particle to fall into dry veld grass while its temperature was between 300 and 400°C or above it could cause ignition of the grass. In the present paper, ignition of the veld grass is determined by the temperature-trajectory history of hot particles of different sizes and initial conditions after their projection into a high velocity gusting airstream. This paper complements that of Mills and Xu Hang on trajectories of sparks from arcing aluminum cables [2] and that of Fernandez-Pello and Tse on the flight paths of metal particles and embers generated by power lines in high winds—a potential source of wildland fires [3]. The present study was commissioned in an attempt to establish the likelihood, or otherwise, that the occurrence of a particular veld fire could have been due to hot aluminium particles ejected from the clashing of high voltage overhead transmission lines. From in situ measurements, the fire started some 10.7 m horizontally from the clashing of the overhead conductors. Sets of graphs were obtained by computational experiment with the objective of verifying the starting point of the fire. These sets comprised: Time versus Particle Temperature, Time versus Vertical Penetration, Time versus Horizontal Penetration and Horizontal Penetration versus Vertical Penetration. Not all of the set of graphs satisfied the requirement of starting a fire at the given point. Sets H, I and J provided the definitive clue that the fire would have started by hot aluminium particles. The investigation was done in phases corresponding to the different set of graphs. Two models were subsequently elaborated called herein less rigorous and more rigorous. The effects of downward, upward and negative horizontal ejection velocities were also examined. The aim of the paper was to reconstruct the conditions prevailing on the day of the fire. The results obtained show that the probability the fire having been started by the hot aluminium particles ejected by clashing overhead conductors was high.

Fire and restoration of the largest urban forest of the world in Rio de Janeiro City, Brazil

National Park of Tijuca in Rio de Janeiro (Brazil) is about 3,300 ha and considered the largest urban forest in the world. Its floristic composition is typical of Atlantic Rain Forest. The reserve is being altered because of fire occurrences and urban expansion. This study identified locations and causes of forest fires, and makes management recommendations to restore damaged areas. From 1991 to 2000, forest firefighters recorded an average of 75-fire occurrences/year. Identified causes included hot air balloons (24%), intentional (24%), rubbish burning (21%) and religious practices (17%). Primary fuels included invasive grasses and ferns. Although hot air balloons destroyed larger areas of forest in each occurrence, a greater number of fires started in the invasive vegetation along roads that bisect the forest. In response to recurrent forests, invasive vegetation has spread gradually into the forest increasing forest degradation. To decrease fire damage, sites with high fire frequencies and density of invasive vegetation were planted with less flammable species. Results indicate that fire frequency decreased and density of invasive vegetation declined. This approach appears to prevent fire incidence, reduce the need for fire fighting, and preserve existing biodiversity.

PAHs composition of surface marine sediments: a comparison to potential local sources in Todos Santos Bay, B.C., Mexico

The analysis of the 16 polyaromatic hydrocarbons (PAHs) listed as priority pollutants by EPA, was carried out on surface sediments at 32 stations at Todos Santos Bay, Baja California, Mexico. The purpose was to investigate concentration levels, distribution patterns and relate them to three suspected local sources. The PAHs composition of car exhaust, grass and shrubs combustion, and asphalt and tire dust, were all compared to the relative abundance of PAHs signature found on marine sediments of the bay. We used GC–MS analysis in selected ion monitoring (SIM) mode. The total concentration found was low (from 7.6 to 813 ng/g of dry sediment. The average concentration was 96 ng/g). PAHs concentration was somewhat correlated ( r 2=0.612; P<0.05) with organic matter content. Surface distributions suggest depositional patterns conforming to the reported water circulation in the bay. The maximum concentration was found near Todos Santos Canyon. The largest concentrations found were those of fluoranthene (120.6 ng/g), Indene(1,2,3-c,d)pyrene (115.6 ng/g) and pyrene (109.9 ng/g). Percentagewise, the main components were PAHs with three and four rings. Several indexes were used to investigate origins including simple PAH ratios and ternary plots. These indexes and plots suggest the main origin as a combination of urban air and wood and brush fires with little influence of oil.

Fire residuals as habitat reserves for epigaeic beetles (Coleoptera: Carabidae and Staphylinidae)

We studied litter-dwelling beetles (Coleoptera: Carabidae and Staphylinidae) in residual patches of unburned forests (fire residuals) left by two natural wildfires in high-elevation coniferous forests in western Alberta, Canada. Fire residuals were wet, late-successional patches of fir and spruce stands, and served as refugia for populations of forest-dwelling beetle species. The largest fire residuals contained older living trees than the mature forest surrounding the burnt areas. Pterostichus empetricola, a glacial relict beetle species, was associated only with habitats provided by the fire residuals. Although there was no relationship between the size of fire residuals and beetle diversity or activity-abundance, more Nebria crassicornis were collected per trap in larger residuals, suggesting dependence of this species on late-seral attributes present within the largest residuals. Conservation of habitats equivalent to fire residuals in managed forests will likely contribute to landscape continuity and preservation of faunal elements common in wildfire-origin landscapes.

Multielement composition of the aerosols of the forest fires of boreal forests upon burning of forest combustibles

The results of the SRXFA determination of the multielement composition of aerosols forming on fires in the boreal forests of Siberia are given. A comparison of the multielement composition of aerosols in the convective column of large forest fires and smoke plumes of surface fires with that of atmospheric aerosols of the Siberian region shows that the mass concentration of all analyzed elements exceeds the background values upon fires. A substantial change is observed in the quantitative composition of the aerosols.

ECOLOGY OF WILD EMMER WHEAT IN MEDITERRANEAN GRASSLANDS IN GALILEE

Aaronsohn in 1909 noted that Triticum dicoccoides was found mainly in rocky habitats. Recent research in Mediterranean grasslands in Galilee supports the hypothesis that rocks served as refuges from intensive grazing. Although proximity of rocks enhances early germination of Triticum, cattle grazing intensity is the major factor determining its abundance. At high grazing intensity, it is absent or survives only among rocks. At moderate grazing intensity it is common not only near rocks. In ungrazed sites it sometimes becomes dominant, but in the long term is often suppressed by perennial grasses. Fitness of Triticum plants in intensively grazed populations was only half that of plants in ungrazed populations, mainly because of damage to maturing ears. After grass fires, Triticum cover increased in ungrazed grasslands, as the cover of perennials was reduced. In ungrazed or lightly grazed grasslands, severe reductions of Triticum populations were observed during population eruptions of the Levant vole, foll...

Extension needs of small-scale dairy farmers in the North-Eastern Free State

The study evaluated the management practices of small-scale dairy farmers in the North-Eastern Free State. The sample area focused on farmers (on communal and state land farms) in the former self-governing territory of Qwaqwa, as well as in parts of the Harrismith, Kestell and Bethlehem districts where newly settled land-reform beneficiaries are concentrated. In this study it was found that most of the problems experienced by the farmers were related to the unresolved land tenure system (communal land), as well as shortage of water, lack of working capital, untimely veld fires, lack of co-operation among farmers (farming group schemes) and inadequate extension services to advise small-scale dairy farmers. Due to a lack of mechanical implements, all the small-scale dairy farmers in the sample made use of manual labour. Knowledge, skills, training and co-operation among themselves were identified by the respondents as being prerequisites for success. Future interventions aimed at improving and strengthening the sustainability and the livelihoods of the small-scale dairy farmers, thereby ensuring equity and reducing economic vulnerability of small-scale dairy projects, should take into account a number of different factors. With regard to extension, government should endeavour to provide an effective service, thereby establishing links with formal channels of marketing, as well as local markets and informal marketing systems, training in farming principles, financial assistance, assistance in acquiring a farm or more land, improving environmental conservation and promoting social infrastructure. The study also reveals that mixed farming should be promoted, since it is unlikely that small-scale farmers can make a living purely from dairying.