Evaristo Eduardo de Miranda

Forest Cover Changes in Tropical South and Central America from 1990 to 2005 and Related Carbon Emissions and Removals

This paper outlines the methods and results for monitoring forest change and resulting carbon emissions for the 1990–2000 and 200–2005 periods carried out over tropical Central and South America. To produce our forest change estimates we used a systematic sample of medium resolution satellite data processed to forest change maps covering 1230 sites of 20 km by 20 km, each located at the degree confluence. Biomass data were spatially associated to each individual sample site so that annual carbon emissions could be estimated. For our study area we estimate that forest cover in the study area had fallen from 763 Mha (s.e. 10 Mha) in 1990 to 715 Mha (s.e. 10 Mha) in 2005. During the same period other wooded land (i.e., non-forest woody vegetation) had fallen from 191 Mha (s.e. 5.5 Mha) to 184 Mha (s.e. 5.5 Mha). This equates to an annual gross loss of 3.74 Mha∙y−1 of forests (0.50% annually) between 1990 and 2000, rising to 4.40 Mha∙y−1 in the early 2000s (0.61% annually), with Brazil accounting for 69% of the total losses. The annual carbon emissions from the combined loss of forests and other wooded land were calculated to be 482 MtC∙y−1 (s.e. 29 MtC∙y−1) for the 1990s, and 583 MtC∙y−1 (s.e. 48 MtC∙y−1) for the 2000 to 2005 period. Our maximum estimate of sinks from forest regrowth in tropical South America is 92 MtC∙y−1. These estimates of gross emissions correspond well with the national estimates reported by Brazil, however, they are less than half of those reported in a recent study based on the FAO country statistics, highlighting the need for continued research in this area.

A Comparative Study of Landsat TM and SPOT HRG Images for Vegetation Classification in the Brazilian Amazon

Complex forest structure and abundant tree species in the moist tropical regions often cause difficulties in classifying vegetation classes with remotely sensed data. This paper explores improvement in vegetation classification accuracies through a comparative study of different image combinations based on the integration of Landsat Thematic Mapper (TM) and SPOT High Resolution Geometric (HRG) instrument data, as well as the combination of spectral signatures and textures. A maximum likelihood classifier was used to classify the different image combinations into thematic maps. This research indicated that data fusion based on HRG multispectral and panchromatic data slightly improved vegetation classification accuracies: a 3.1 to 4.6 percent increase in the kappa coefficient compared with the classification results based on original HRG or TM multispectral images. A combination of HRG spectral signatures and two textural images improved the kappa coefficient by 6.3 percent compared with pure HRG multispectral images. The textural images based on entropy or second-moment texture measures with a window size of 9 pixels × 9 pixels played an important role in improving vegetation classification accuracy. Overall, optical remote-sensing data are still insufficient for accurate vegetation classifications in the Amazon basin.

Brazilian rain forest colonization and biodiversity

Abstract This work explains the tropical rain forests main characteristics, and the reasons why this ecosystem play an important role in determining global biodiversity. The occupation process of the two Brazilian tropical rain forests (Atlantic and Amazon) are briefly described, with quantitative information on deforestation and its consequences. Human presence in these areas is millenary, and its role as a source of inrease, decrease and maintenance of biodiversity are exemplified. Different kinds of man/forest interactions (such as those characterizing indigenous people, riverside communities, caboclos, rubber tappers and agriculturis) and their relation to biodiversity, are desribed. The future occupational of the Brazilian tropical rain forest supplanting past mistakes, especially in the Amazon, is proposed as a triple challenge. The first challenge is to stop the destruction of the still-intact forest, and to plan its rational occupation. An example of how this has been done by rubber tappers in the state of Acre, and how it affects wildlife and vegetation communities is given. The second challenge is to reduce the migration flow towards the economic frontier areas, and to propose to the thousands of agriculturists already installed there alternatives to reconcile economic development and environmental preservation. In this case, the situation of a colonization project in the state of Rondonia is described. The third challenge is to restore the biodiversity in the almost 400 000 km2 of land that have been occupied and degraded for a long time, as in the state of Tocantins. An example of how scientific research contributes to meeting this challenge is described.