Background: It is not easy to assess the amount of burned vegetation (forests, pastures) per year in Argentina. According to official statistics recorded by the Dirección de Producción Forestal more than one million hectares are burnt annually. But this figure underestimates the real ocurrence of fires. Only a few provinces have an efficient system of collecting information. In most cases the data are incomplete or do not contain useful information. Therefore a very conservative figure of the real annual area burned is at least 1.5 million hectares.
Considering the fact that more than 70% of the area affected by fires are grazing lands, we thought that an enquiry would be an appropriate way to establish contacts with a large number of ranchers.
The objective of the enquiry was to evaluate types of vegetation affected by fire, economic losses, cause of the fires, extent and reasons for use of prescribed fire, and measures of precaution, including cooperation with the authorities, and to determine if an anonymous enquiry is a right approach to obtain feasible information.
Another main goal of the enquiry was to obtain information from ranchers about their views/perceptions of fire. Such information is an important base for development of a fire management plan.
At this stage of the enquiry 680 questionnaires were mailed to ranchers in ten provinces. Most answers came from four provinces: Mendoza, La Pampa, Santa Fe and Corrientes. Out of the 680 letters delivered to these provinces 97 replies were received.
Details of the results of the enquiry are published elsewhere (see below). In this short report we provide some of the most interesting findings.
Results and Conclusions: Although only 14% of the questionnaires were returned, the ranchers had a strong inclination to answer the enquiry. Within this group, 58% considered the fire problem as a high priority matter in their region.
Of course the limited amount of replies does not permit to extrapolate the results to a whole region or province. The information obtained on fire causes show some differences in various provinces, e.g. most apparent in the case of lightning (Fig.1).
According to the answers of the ranchers, almost a half of them practice prescribed burning. The main purpose of this is to stimulate the growth of grass, the grazing resource for cattle. As a simple consequence of this, the principal vegetation type affected by fire was pure grassland, followed by grassland with isolated trees.
On account of the subjects considered when they do a prescribed fire, the items most chosen were: wind speed, to burn with or against the wind, and hour of the day. All ranchers that answered this question considered at least two items before to starting a prescribed fire (they could chose among the following items: hour of the day, wind speed, temperature, relative humidity, fuel moisture, weather forecast, to burn with or against the wind, and “nothing”).
The answers to one of the questions (“In the case of a wildfire whom do you ask for help?”) reflect the poor trust of ranchers in counties and/or provincial agencies (Fig.2). When they cannot control the fire themselves, most of ranchers (44%) go to their neighbours for help, although only one in four of the ranchers are organized in any way, e.g. in consortia.
The average of total economic losses per ranch is 1.21 $/ha (Tab.1). Greatest economic losses were recorded in Mendoza (1.55 $/ha), where only 12.5% of ranchers practice prescribed burning. Smallest losses were recorded in La Pampa, where a little more than a half of the ranchers are practising prescribed burning.
Fig.1. Sources of wildfires causing economic damages
Fig.2. Actions taken by ranchers if a wildfire occurs on their land and fire-fighting support is needed
A: call neighbours; B: call the fire brigade; C: organized system available of reciprocal help with neighbours; D: call the county authorities; E: call the police; F: call the civil defense
Tab.1. Average data on ranch sizes, fires and economic losses in the four Argentinian provinces Mendoza, La Pampa, Santa Fe, and Corrientes
MendozaLa PampaSanta FeCorrientesTotal (Average) Average size of ranch (ha) 10,598 6,671 3,118 9,590 6,007 Annual area burned (ha) 590.2 780.3 218.8 2,568.8 772.0 Annual percentage of each ranch burned 5.5 11.7 7.0 26.8 12.8 Economic losses per ranch * 16,500 6,833 4,394 – 7,298 Economic losses/ha per ranch ($/ha) 1.55 1.02 1.41 – 1.21 Economic losses/ha burned per ranch ($/ha) 27.9 8.75 20.08 – 9.45 Mean Fire Return Interval of the whole area of average-sized ranch (years) 18.0 8.5 14.3 3.7 7.8
1 Argentina $ = 1 US $
In the same way, in Mendoza, the economic losses per burned hectare reach the highest values (27.9 $/ha), and in La Pampa, the lowest (8,75 $/ha burned). The value mentioned for Mendoza is three times the average for all the provinces considered (9.45 $/ha burned). It is important to point out that both economic losses per hectare and economic losses per burned hectare are direct losses. For example they do not consider the reduced income in the post-fire years.
Fire recurrence (= mean fire return interval [MFRI]) and the annual burned area can also provide an idea of the importance of fire in each province. In La Pampa, for example, the MFRI for the whole area of an average-sized ranch is 8.5 years, in Mendoza 17.9 years, in Santa Fe 14.25 years, and in Corrientes 3.7 years.
Finally, an anonymous enquiry can be an easy way of getting quick and abundant information from the ranchers. But this kind of approach does not allow detailed information of many practises or a better assessment of economic losses.
The detailed results of the enquiry are published in:
Tesolin, O., H.Zucchini, y J.G.Goldammer 1994. Encuesta piloto: Evaluación de perdidas económicas ocasionadas por incendios de campos y uso del fuego por productores ganaderos. Revista Agrocpecuaria, Forestación, Julio 1994, 34-51. Editorial Agropecuaria Hemisferio Sur, Montevideo, Uruguay.
The research project was carried out in cooperation with the Fire Ecology and Biomass Burning Research Group, Max Planck Institute for Chemistry, Biogeochemistry Department, Germany.
From: Omar Tesolin and Hugo Zucchini Address: Secretaria de Agricultura, Ganaderia y Pesca Dirección de Producción Forestal Av. Paseo Colón 982 ARG-1063 Buenos Aires