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Article Excerpt
In 1998 I attempted to cross the rugged Sierra Madre Occidental from Sinoquipe to Cucurpe. Despite the aid of good Mexican topographic maps, I lost my way on dirt roads that forever forked on the ejido lands of northeast Sonora. Instead of the beautiful, unused road to Cucurpe, I found three men making charcoal from large mesquite trees growing in riparian areas. At the time I did not realize that mesquite charcoal is produced primarily to satisfy the U.S. demand for a flavorful grilling fuel. Years of subsequent research into the borderland mesquite trade followed this initial discovery. This paper, using mainly ethnographic evidence, documents the impact of a multimillion-dollar trade of wood and charcoal on the dry borderland region of northern Sonora. This impact and current use of the environment is placed in the context of long-term environmental change in the region. Moreover, the use of biomass energy in the borderlands is placed in the context of biomass use around the world, which is the basic form of energy for billions of people around the world.
Conrad Bahre's (1991) classic account of vegetation change in the area, Hastings and Turner's The Changing Mile (1965), and the special double issue of Journal of the Southwest that documents social and environmental aspects of the binational Sonoran Desert Reserves (Felger and Broyles 1997) document environmental history of the dry borderlands region. They stop short, however, of documenting the recent trade in biomass, specifically mesquite wood and charcoal. This trade strips vegetation south of the border to meet demands north of the border. These authors do, however, leave readers with a vivid image of the "mesquite nemesis." Mesquite is the nemesis of ranchers in the area because it invades cattle pastures (with the help of cattle) and competes with grass for valuable water and sunlight. One could reason, armed with knowledge of how the tenacious mesquite tree (in this case Prosopis velutina) (1) infested many grasslands of the Arizona-Sonora borderland since the introduction of cattle, that charcoal and firewood production on Sonoran ejidos may not adversely impact ejido environments and sustainability because encroaching mesquite trees are eliminated. Research conducted for this paper revealed, contrary to these expectations, that charcoal production and firewood harvesting for export do not utilize the scrubby type of mesquite that invades pastures and hillsides. Instead, carboneros (charcoal makers) and leneros (woodcutters) take advantage of large, mature mesquite and ironwood trees growing in riparian areas. This paper, then, documents the details of the production, use, and trade of mesquite wood and charcoal in the Sonora-Arizona borderlands and relates current use of mesquite to the changes in mesquite use and density over several thousand years. It then discusses the ramifications of mesquite harvesting on the environment.
METHODS
Results presented in this paper rely on qualitative information collected in cooperation with residents of the region over a five-year period. The often illicit and diffuse nature of the charcoal and firewood business, in addition to the booming drug trade in the area (Perramond 1996; Yetman and Burquez 1998) forced my gradual introduction to its main protagonists in remote, rural areas of Sonora. I chose to participate in daily activities and interview members in Ejidos La Arizona, La Cebolla, and San Juan in the Tubutama/Saric area, and Ejido El Berrendo in the Sonoyta/Lukeville area (figure 1). Rather than just interview people and expect candid results, I "soaked and poked" (Bernard 1995). In other words, I participated in daily ejido life. For example, one cold December evening I loaded 22,000 pounds of charcoal into the back of an eighteen-wheel trailer (figure 2, a & b). The carbonero handled the other 22,000 pounds, while four men stacked the forty-pound bags in the trailer ready for the journey to the border at Nogales. (2) This activity formed deep friendships and provided me with an insider's view of ejido management of natural resources. Firsthand observations of the charcoal and wood trade were backed up by data documenting the magnitude of trade in charcoal and firewood from the U.S. Department of Commerce (USDC 1995, 1997, 2001, 2002; see tables 1 and 2).
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BACKGROUND: A HISTORY OF MESQUITE USE IN THE BORDERLANDS
This history is provided to place current use of mesquite in a longer perspective and to show how use and density of mesquite in the borderlands have changed over time. Native people of Arizona and Sonora utilized, and continue to use, every part of the mesquite tree. Mesquite served as a primary source for food, fuel, shelter, medicine, weapons, and tools (Felger 1977). Because mesquite was and is so prevalent in the dry borderland, it can be relied upon as a constant source of nourishment when all other food sources fail (Rogers 2000; Yetman and Burquez 1998).
The quasi-stable relationship between desert grasslands and desert scrub responds to several human-induced factors. The density (not range) of mesquite trees in the dry borderland area that was established during centuries of use by indigenous populations increased due to cattle grazing of grasslands and fire exclusion beginning with the arrival of Spanish colonists (Harris, 1966; Fisher 1977; Bahre 1991; Bahre and Bradbury 1978; Burquez and Martinez-Yrizar 1997). Spanish colonists introduced cattle and other livestock to the region before the 1880s (Bahre 1991; West 1993), but the real boom in cattle ranching and large-scale modification of the environment began when the Southern Pacific Railroad reached southern Arizona. Southeastern Arizona supported almost 400,000 head at the end of the nineteenth century (Bahre 1991). As mesquite density increased in the Arizona-Sonora borderland, its morphology changed from single-stemmed, large individuals to smaller, multi-stemmed individuals (figure 3, a & b). If the principal growth stem of mesquite is disturbed in any fashion, such as through trampling by livestock, underground buds initiate new growth around the base of the plant, which results in smaller, multi-stemmed trees (Fisher 1977; Simpson and Solbrig 1977). It is important to relate recent changes in mesquite morphology and density to the recent Holocene record of climate and vegetation history in the area. Indeed, mesquite growth outside of desert washes as is seen today, albeit with the help of cattle and humans, is not new to southern Arizona and northern Mexico. During the Holocene (12,000 years BP to the present) mesquite grew in areas that are now too dry. It was only about 3,800 years BP, and in some areas as late as 1,000 years BP, that mesquite retreated to nearby washes (Turner, Bowers, and Burgess 1995). In Arizona the only regions of mature, single-stemmed mesquite occur in relatively undisturbed areas along desert washes (Felger 1997; Simpson and Solbrig 1977).
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The mines of Sonora and Arizona made extensive use of mesquite and...
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