2.2 Forest Fire Situation in Mexico
Mexican Biodiversity
There are more than 170 countries in the World. Out of these, 12 alone harbor between 60 and 70% of the total biodiversity of the planet and thus earn the privilege to being called megadiverse. With a territorial extension of 1,964,375 km2, Mexico is (together with Brazil, Colombia and Indonesia), at the very top of the list, taking first place in reptile diversity, second for mammals, fourth for amphibians and vascular plants and tenth for birds. It is estimated that more than 10% of all the species in the world live in Mexico (CONABIO12002) [24]. The complex topography of the country, and the changes running along the latitudinal continuum create an enormous number of environmental variants. The changes in altitude produce climatic variations such as the intensity of solar radiation, atmospherical humidity, and diurnal oscillation of temperature (CONABIO 2002) [24].
Natural Resources Framework
Coniferous forest dominated by pines, mixed conifer-hardwood forest, and hardwood forest cover 32.8 millon ha. If tropical rain forest is included, about 50 millon ha of the land is covered by forest (Fig. 2.6). Around 80% of the forest surface belongs to ejidos2 and communities, 15% is privately owned, and 5% belongs to the federal government. The main wood species in the country, in terms of the surface covered and economic importance, are Pinus and Quercus species, which represent approxi-mately 80% and 5% of the total national timber production in Mexico, respectively (CONAFOR 2001) [27].
1National Commission for the Knowledge and Use of Biodiversity
2An Ejido is agricultural land expropriated from large private holdings and redistributed to communal farms (Bartleby, 2003) [124]. While the concept of the ejido in Mexico is prehispanic, most of the fundamental ideas and concepts that created what an ejido is today stem from the theories of democratic communism.
Figure2.6:TypesofvegetationinMexico(SEMERNAT2004)[132].
2.2. Forest Fire Situation in Mexico 17
Forest Fires and Political Response
Nationwide, temporal and spatial occurrences of forest fires vary widely depending on local and topographic conditions. Another important factor is the accessibility for humans beings, which influences the utilization of natural resources. In the last decade, fire has become a more frequent phenomenon in protected areas such as national parks and biosphere reserves, as a consequence of the increased frequency of visitors (Jardel 2001) [73]. Furthermore, wildland fires tend to be associated with deforestation and degradation processes, since fire was and still is utilized to convert forests and other types of vegetation into agricultural fields or pastures.
In 1998, Mexico experienced the worst drought in 70 years and an extraordinary fire season. Meteorological conditions associated with the extreme dry conditions of
“El Ni˜no” facilitated the occurrence of forest fires. Wildland fire incidences in 1998 exceeded the recorded incidences of the five previous years combined and caused severe damage in different regions of the country. Near the end of the regular fire season in the majority of the territory, approximately 13,000 fires affected 440,000 hectares (Fig. 2.7) (IFFN 1998, 1999) [57, 58].
Figure 2.7: Comparison of burned areas in 1998 to those of the previous five years from 1992-97 (Global Fire Monitoring Center 1999) [58].
It is estimated that 26% of the burned landscapes were forests, 32% grasslands, and 42% shrublands. Around 94% of the wildland fires were of human origin and 6%
of the causes were unknown (CONABIO 2004, IFFN 1998) [25, 57].
The awareness of the ecological role of fire has risen in Mexico following the dev-astating wildfires of 1998. Numerous authors have noted that fire is an important ecological process (Fern´andez and Garc´ıa-Gil 1998) [40]. But in the aftermath of harmful fires, some initial reactions have focused on law enforcement which attempts to control human-caused ignitions, irrespective of the complex social problems that lead to deforestation (Curiel Ballesteros 1998) [6]. Since 1998, the Mexican govern-ment has begun a campaign to increase forest fire suppression capacity. Prevention, combat, and suppression are the new policy approaches to wildland fires in Mexican forests and protected areas. This policy seems to be based on a negative perception of the role of forest fires in forest ecosystems among the environmental sector, and public opinion (Jardel 2001) [73].
Before 1998, the occurrence of wildland fire was not recorded systematically and important investigations on the frequency (or intervals), the intensity, and the effects of wildland fires on biodiversity or vegetation succession were not carried out in Mexico. Hence, the knowledge in Mexico about fire history, dependence, and the regime of wildland fires was insufficient for the development or design of adequate forest fire management strategies (Fule 1994, Jardel 2003, Rodriguez-Trejo 2003) [47, 74, 125].
According to the records and extrapolations to the statistics of the Mexican agen-cies CONABIO (2004) and CONAFOR3 (2004) [25, 28], there exists an increasing tendency with respect to the occurrence of forest fires in the last 30 years (Fig 2.8).
Figure 2.8: Number of wildland fires per year from 1970-2004 based on records and extrapolations (CONABIO 2004, CONAFOR) [25, 28].
3Forest National Commission
2.2. Forest Fire Situation in Mexico 19 Mexico is currently starting a collaboration project with the NGO (non-governmental organization) “The Nature Conservancy’s Fire Initiative”, and together with other Mexican conservation partners, they have established the “National Fire Management Forum”. This forum includes government officials, land managers, scientists, and fire experts. It is now creating a network and a monitoring program with international teams of fire experts, mainly from USA and Mexico, in order to develop ecological and socially adequate fire management strategies.
Another important program that emerged from the fire season of 1998 was initi-ated by the Mexican agency CONABIO. They established a software program which detects so called hot spots by remote sensoring techniques. A hot spot may be caused by camp fires, factories, insolated soils, or active volcanoes, just to mention some ex-amples. The use of satellite images provides the spatial and temporal location of hot spots on the earth’s surface. This information reflected on a map registers areas where hot spots were detected but does not provide accurate data as to the number of fires and the size of the affected surface (Fig 2.9).
Figure 2.9: Detection of hot spots by satellite images (CONABIO 1999) [26].
Fire Causes
The forest fire season normally occurs between January and July. March and April are the most susceptible fire months, because they coincide with the peak dry season.
About 94% of all wildland fires are caused by human activities, of which 48% are associated with agricultural activities and cattle breeding (Fig 2.10). In tropical zones, the main cause of wildland fires is the intensive use of slash and burn agriculture (FAO 2001, SEMERNAP 1999) [39, 130]. Some studies carried out by SEMERNAP (2002) [131], revealed that only 6% of fires are cause by lightning and undefined causes.
Figure 2.10: Causes of wildland fires in Mexico (CONABIO 2004) [25].