Remote Sensing of Forest Change

Landsat TM   *    Color Landsat TM   *    Landsat False-Color
Images provided below for better understanding of human alteration.

Upon consideration of widespread and rapid deforestation and the Peten's ecology, president of Guatemala, Vinicio Cerezo Arevalo, signed legislation in 1990 creating the Maya Biosphere Reserve. The reserve encompasses approximately 1.6 million hectares of Guatemala's tropical lowland forest and wetland ecosystems. The primary goal of the Maya Biosphere Reserve's Master Plan is the following: "... to yield a harmonious and sustainable development in the region, guaranteeing the stability of the present natural and cultural resources" (Sundberg, 1997). The following NDVI image represents forest change since development of the reserve in 1990. Change detection for this image was acquired by substracting the 1990, 1993, and 1995 NDVI from the 1986 NDVI. The composite was made by loading TM bands 4, 5, and 3 onto red, green, and blue image bands. It is evident the greatest amount of deforestation occured during 1990-1993 and the Belize-Guatemala border saw the greatest increase during 1993-1995.

Global Hydrology and Climate Center

Landsat Thematic Mapper satellite Images from SPIE (The International Society for Optical Engineering).

Landsat Thematic Mapper satellite images of the Peten, in Guatemala, demonstrate the amount of forested land. Note the significant decrease of forested areas from 1986 to 1997 indicated by shades of white. Satellite imagery is a resourceful tool in monitoring environmental change by use of reflective, mid, and thermal infrared spectral bands. Responsive to amount of present vegetation, plant vigor, and soil conditions, Thematic Mapper satellite images provide substantial evidence to deforestation and soil erosion.

1986                  1997
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Color Landsat TM Images taken from USGS

The following color Landsat TM images show a 15yr duration progression broken into three intervals. All images were acquired in April to show consistency and avoid error caused by seasonal factors such as cloud cover. Landsat Thematic Mapper spectral bands are capable of demonstrating green reflectance and chlorophyll absorbtion of healthy vegetation. Furthermore, some spectral bands are sensitive to soil conditions and plant mositure providing additional information on deforestation patterns and soil erosion in the Peten Region. The bottom half of all three images is the focus of land clearance where green is indicative of vegetation and brown-pink represents bare soil. Note the decrease of vegetation from 1986 to 2001 as deforestation continues throughout the region. It is important to keep in mind that if cutting rates continue, only 2% of the forest will remain 10 years from now (Sever, 1998). This is a significant amount given that presently 40% of the forest remains.

14 April, 1986

23 April, 1993

7 April, 2001

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False-color composite. Acquired from FAMSI (Foundation for the Advancement of Mesoamerican Studies, Inc.)

Bajos, shown in purple to dark pink, represent flooded swamp areas and make up about 40% of the land surface in the Peten (Carts-Powell, 2000). Population concentrated and farming occurred where water sources were readily available. The significance of such data provides an analysis of the ecology surrounding the vulnerable region. False-color composite imagery emphasizes the ratio of arable land to swamp areas.

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