Portland State University. Department of Geography
Andrew G. Fountain
Date of Award
Master of Science (M.S.) in Geography
1 online resource. Digitized computer-produced typeface, maps (some col.)
Landscape ecology, Forest landscape design, Forest landscape management, Remote sensing
The Meseta Purepecha, a volcanic plateau in the Mexican state of Michoacan, is home to one of the most species-rich pine forests in the world. Recent increases in demand for forest products has put added pressure on these resources. Though existing research has suggested significant deforestation in the Meseta, there is little information identifying specific areas of decline. This study focuses on two indigenous communities in the Meseta-Pichataro and Sevina. Both communities have long relied on wood as an economic resource. However, the two communities have reacted differently to increased demand for forest resources. The purpose of this study is to identify the differences in the rate and extent of forest change between Pichataro and Sevina.
Three dates of Landsat satellite images - 1976, 1986, and 2000-were used to identify changes in the Meseta's forests. Supervised classification was used to classify the 2000 image into forested and non-forested areas. Change detection was performed on the 1976 through 2000 images to identify areas of forest clearing and forest regrowth. The 2000 image was then used as a reference for generating maps of historic forest extent based on the change detection results.
Results show that between 1986 and 2000, Sevina cleared approximately 16% of its forested land between while Pichataro experienced a net gain of 7%. In the same period, 93% of the deforestation in the combined study area occurred within the community boundary of Sevina, which manages only 35% of the study area forests. Sevina's remaining forests are also more isolated and fragmented than the forests of Pichataro. The differences between the two communities appear related to management practices. Sevina has relied on larger-scale timber harvesting to derive economic benefits from its forests. Pichataro has focused on local harvesting and value-added production.
Martin, Kevin Scott, "Comparing Twenty-Four Years of Forest Change in Two Communities of Mexico's Meseta Purépecha Using Multi-Spectral Satellite Imagery" (2004). Dissertations and Theses. Paper 2428.