Landscapes Forest and Global Change - ESA - Escola Superior ...

J. Schaefer-Santos & C. Lingnau 2010. Landscapes in Transition – Monitoring in Areas of Landslides
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showed reliable results for detecting changes in forest areas damaged by wind and snow sliding
snow in Sweden and Finland. The procedures used by the authors based on the simple
difference of multitemporal images of the spectral bands of red and of mid infrared and change
detection pixel to pixel and neighborly relations. The mid infrared, especially, pointed to change
in areas of climax forest in which there was the removal of timber, and therefore this technique
very effective for monitoring forest. In this study we sought, through the vegetation index found
that deforestation could be a predominant factor in landslides occurred in the study area in
November 2008 which caused the death of 135 people for burial and for such were used images
Landsat 5 TM.
2. Methodology
The study area is located in the Itajaí Basin, which lies between latitudes 26º20’ e 27º50’ e
longitudes 48º40’ e 50º20’, extending for 150 km north to south and 155 km from east to west
(Gaplan, 1988). The study area is located from the middle course of the river Itajaí, and it parts
of the Middle subbacia Itajaí and part of Rio subbacia Luis Alves, encompassing the areas of
disaster in 2008 (Figure 1). In the watershed area of the Rio Itajaí various formations are found
among the Dense Atlantic Rain Forest and some nuclei of Araucaria Forest in the high Itajaí
Valley. In the middle and lower regions of Itajai Valley, there is the Dense Atlantic Rain
Forest, especially characterized by high density and high species richness of trees, saplings and
shrubs, and high density of epiphytes. (Klein, 1978).
The study used 4 images as mentioned below:
1. 10/6/1992;
2. 30/6/1999;
3. 4/6/2007;
4. 1/2/2009.
The images were so selected because they are of the same month (June) acquisition, except the
last. The choice of images from the same month, minimized the differences in reflectance due to
the effects of phenology of forest and shade relief. The relief shading in images acquired in
similar periods of the year, for example, in the same month, the shaded areas are virtually
coincident, due to the similarity of the angle of inclination and azimuth of the sun. The image
had to be t4 February, for not having another cloudless after the environmental disaster.
Figura 1: Study area localization.
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.