Transcript 40.2-P.ppt
SOCIO-SPATIAL PROCESS OF FOREST FRAGMENTATION IN THE BRAZILIAN AMAZON: the case of Uruara colonization site Eustáquio Reis, IPEA Alexander Pfaff, Columbia University Jaiguo Qi, Michigan State University Carlos Souza, Jr. IMAZON MICHIGAN STATE U N I V E R S I TY 1. INTRODUCTION Two important topics, recently addressed in Science, have emerged. The first concerns rates of deforestation and scenarios of the likely future extent of cleared lands (Laurence et al., 2001). The second concerns policy responses and the potential role of frontier governance in mitigating excessive forest loss (Nepstad et al., 2002). This poster addresses the spatial aspect of deforestation, and in particular the forces leading to the fishbone pattern of forest fragmentation, in order to inform the policy debate. This figure suggests a low level of impact overall, probably because the highway has remained unpaved for thirty years. Deforestation fractions in the first three bands (0-10, 11-25, and 26-50 kilometers) are 30, 13 and 3 percent, which compare to the averages reported by Laurance and colleagues of 30, 20, and 15 percent Laurance and colleagues do not describe how forest degradation and loss arise from human activities. Our approach is to consider landscape evolution following in the wake of the early infrastructure investment in Uruara. Also, we consider the many political and economic decisions leading to the massive infrastructure investments of the late 1960s and early 1970s. 2. BACKGROUND AND METHODOLOGY % Deforestation Our methodology is a descriptive case study of land cover change in Uruara, a colonization frontier established by the INCRA in the early 1970s in the Brazilian state, Pará. The study focuses on the primitive transportation corridor we refer to as the settlement road. These roads were originally constructed -- and continue to be extended -- to provide access to land The Brazilian government took jurisdiction from individual states of a 100 kilometer strip of land 0.30 0.25 Percent off the development highways that were built pursuant to federal. 0.35 0.20 Figure 4: Uruara Ave. Lot., 1978 0.15 on both sides of all development highways, and INCRA was given administrative responsibility for 0.10 the first 10 kilometers in the interest of smallholder colonization. The remaining 90 kilometers were 0.05 left available for unspecified economic development initiatives. To facilitate occupation in a number of areas, INCRA constructed initial spurs out to about 6 kilometers from the highways. In accordance with plans for colonization based on 100 hectare lots, the spurs (Travessoes) were spaced 5 kilometers apart. This provided 500 x 2000 m lots along the main highway, and 400 x 2500m lots out along the roads (Figure 1). Since the federal government only built the original spurs, the fishbone pattern emerges on the basis of private actors and local government. The process of colonization is still active, as indicated by the assentamentos on the figure, all of which were implemented after 1995. In general, the specific form of colonization addressed by this poster, in social and spatial terms, is that of smallholder. Figure 4 gives the land distribution in the settlement area, which includes mostly small holdings. 0.00 3. THE PRIMARY OBJECTIVE OF THIS POSTER The primary objective of this poster is to account for the path dependent spatial processes that has generated the fishbone landscape of Figure 1. 4. THE SOCIAL PROCESS In a study published in Science, Laurance and colleagues provide a basin-wide projection of Amazon land cover under optimistic and pessimistic scenarios of development and occupation. While an explicit model is left unstated, a Thünian framework is utilized , with degradation decreasing with distance from infrastructure. Figure 2 shows deforestation in the study area as a function of distance from the region’s development highway, using the buffers described in Laurence. Initially loggers took advantage of the free-ride provided by federal road building. With the construction of the development highway and picadas, the mahogany frontier was activated in advance of agriculture, and the first wave of logging passed through the region. Wood extraction declined with the exhaustion of easily accessible trees. As the agricultural frontier filled in and extended itself through the early 1980s, forest accessibility was enhanced again, and the loggers returned to take advantage of new species such as cedro, ipê, and jatobá. The colonists constituted a social force to be reckoned with, necessitating a cooperative and mutually beneficial approach to forest exploitation. Road building by loggers took several forms bearing directly on fragmentation patterns. Two main thrusts: the loggers stepped-in for government in the areas sanctioned for colonization, and also extended roads into unclaimed lands, so-called terra devoluta. In both cases, road extensions were driven by the loggers’ desire to maximize profits, in the first instance by taking logs off properties in the colonization area, in the second by harvesting in terra devoluta free of charge, following new road segments mapped exclusively by the loggers themselves. 4.3 Taking land from the union 0 - 10 10 - 25 25 - 50 50 - 75 75 - 100 over 100 Buffers (Km) Figure 2: Deforestation measured in distance buffers from the study areas development highway, following Laurence. Measured by ETM+ satellite imagery, 1999. 4.1 Initial colonization 1970 - 1975 Colonization begins in Uruara with a survey conducted to about 10 kilometers, which is consistent with original federal intentions to create a colonization zone of 10 kilometers on either side of the development highways. Occupation of land followed immediately as colonists themselves constructed trails, or picadas, to claim and to access properties. Given that picadas are little more than paths through the forest, the colonists pressured “government” to return with earth-moving equipment, which it did, and the settlement roads were opened to 10 kilometers. In the case of Uruara but no doubt more generally (e.g., Rondonia), the initial surveys and property demarcations did not meet the demand for land that soon emerged in the wake of the initial colonization impulse. Colonists produced new households as their children aged and formed families, with their own demands for land. Figure 3 shows one familial network for a settlement road in the Uruara region; the dense relationship web stems from chain migration, pronounced in frontier settings, and from family formations by colonist children. As these demographic pressures mounted in Uruara, colonists extended the colonization grid on their own initiative by cutting new picadas and marking 100-hectare lots. Colonists reproduced the original colonization geometry and, by implication, the orthogonal fishbone of the road system, hoping that government would regularize their new holdings . The federal government obliged, and extended the colonization zone with another survey, in 1980 or thereabouts, to between 20 and 30 kilometers off the development highway. Completion of the second survey set the stage for another road building episode, this one to the limits of the newly expanded zone of colonization where INCRA was largely absent, and the task was accomplished by the newly formed municipal government and by loggers. The Brazilian Constitution allows small holders access to terra devoluta through direito de posse (squatter’s rights) and usocapião (usufruct rights) after demonstrating productive use for a year and a day. This enables colonists to provide loggers with access to wood through a loophole in the law. Upon occupying both terras devolutas and land at the limits of sanctioned colonization -- with encouragement and material support from loggers -- colonists initiate a land titling process with INCRA, receiving with relative ease a so-called license of occupation. Also, they receive an authorization to deforest from IBAMA, which allows for land clearance from 20 percent of the holding. The landscape effect: once the trees have been removed, the loggers buy the land from the colonists, consolidate contiguous parcels into large properties (Figure 5). Often, colonization is supported far from development highways with the creation of new assetamentos, typically following smallholder occupation (figure 1). This leads to linear extensions of the existing settlement roads. In sum, the social processes governing land use and occupation in the micro frontier of Uruara involved household demography and profit maximization. D is t a n c e t o m a in r o a d ( k m ) Marcellus Caldas, Michigan State University Robert Walker, Michigan State University Stephen Perz, University of Florida Eugenio Arima, Michigan State University 4.2 Logger involvement 50 45 40 35 30 25 20 15 10 5 0 1970 Landsat ETM, 1999 IKONOS, 2001 Figure 5: Property consolidation in Uruara 5. THE SPATIAL PROCESS Quickbird, July 8, 2002 1975 1980 1985 1990 1995 2000 Y e a r o f O c c u p a tio n Figure 6: Distance from Development Highway verses year lot was first occupied. The first spatial outcome involves occupation of the original INCRA lots by colonists, and the implementation of their farming systems. The second survey and extension of the colonization area follow, as new demands for land emerge. The spatial effect is to sustain an element of inertia in the evolution of the colonization space, with relatively straight settlement roads continuing out to about 25 kilometers and sometimes much further. farming starts later in the new lands, which accounts for the vaguely pyramidal shape of cleared land along the settlement roads in the study area, and in many other colonization sites.. This attenuates with time as land cover change decelerates in the first-zone properties due to household-life-cycle effects, while second-zone properties continue evolving.. Figure 6 demonstrated the staged nature of land occupation in the Uruara colonization frontier. Land settlement prior to about 1980 occurs on properties close to the development highway (≤ 20 kilometers), while distant lots are appropriated later. 6. Conclusion: In sum, the fishbone pattern emerges on the basis of the colonist demand for land, and the desire that properties be regularized by INCRA. It is a long-term process, involving smallholder households, working in conjunction with loggers. In Uruara, the pattern begin emerging in the early 1970s, and extension of parallel roads continue to this day, thirty years later. Anecdotal evidence suggests that the same process underlies the spatial pattern of deforestation in Rondonia.