Brazil's Amazon forest remained largely intact until the modern era of deforestation began with the inauguration of the Transamazon Highway in 1970. Amazonian deforestation rates have trended upward since 1991, with clearing proceeding at a variable but rapid pace. Although Amazonian forests are cut for various reasons, cattle ranching predominates. The large and medium-sized ranches account for about 70% of clearing activity. Profit from beef cattle is only one of the income sources that make deforestation profitable. Forest degradation results from logging, ground fires (facilitated by logging), and the effects of fragmentation and edge formation. Degradation contributes to forest loss. The impacts of deforestation include loss of biodiversity, reduced water cycling (and rainfall), and contributions to global warming. Strategies to slow deforestation include repression through licensing procedures, monitoring, and fines. The severity of penalties for deforestation needs to be sufficient to deter illegal clearing but not so great as to be unenforceable. Policy reform is also needed to address root causes of deforestation, including the role of clearing in establishing land claims Español