RESUMOOs remanescentes florestais da Mata Atlântica têm sofrido pressões antrópicas frequentes. Essas pressões são relacionadas, principalmente, ao desmatamento e aos incêndios florestais. Por isso, o objetivo deste artigo é o desenvolvimento de um mapa geoecológico de susceptibilidade à ocorrência de incêndios no Estado do Rio de Janeiro, na escala de 1:100.000. Para esta proposta, mapas de elementos funcionais e de estrutura da paisagem (forma das encostas, radiação solar, uso da terra e balanço hídrico) foram construídos. O estudo foi conduzido utilizando o método analítico integrativo e diferentes técnicas de geoprocessamento, como Modelos Digitais de Elevação e Sistemas de Informações Geográficas. Os mapas representam três diferentes períodos: anual, seco e chuvoso. Ademais, estes mapas foram validados por meio dos dados do sensor MODIS. Os resultados proporcionaram diferentes arranjos espaciais para a susceptibilidade por meio das classes designadas como alta, média e baixa, que tiveram boa correlação com os dados de validação.Palavras-chave: mapas geoecológicos, incêndios florestais, geoprocessamento. Geoecological Assessment of Wildfire OccurencePotentiality in the State of Rio de Janeiro ABSTRACTThe remaining Atlantic Forest has frequently suffered anthropogenic pressures. These pressures are mainly related to deforestation and wildfires. The purpose of this paper was to develop a geo-ecological susceptibility map of fire occurrences in the State of Rio de Janeiro at 1:100,000 scale. To this end, maps of landscape functions and structures (landforms, solar radiation, land use and water balance) were constructed. The study was conducted using analytical integrative approach and different geo-processing techniques, such as digital elevation models and geographic information systems. These maps represent three different periods: annual, dry and rainy seasons. Moreover, they were validated through the analysis of MODIS sensor data.Results showed different spatial arrangements provided by the susceptibility of classes designated as high, medium and low sensitivity, which correlated well with the validation data.

The city of Rio de Janeiro has two different relief compartments, the coastal massives and flood plain areas. One of these is the Pedra Branca massif, with 197.27 Km², situated in the western part of the municipality, between 22º 55' and 23º 05' S and 43º 20'and 43º 40' W. Pedra Branca has suffered forest fires frequently over its history, which is one of the main actors of its changing landuse. The aim of this paper is to develop a susceptibility map of fires occurrence in the Pedra Branca massif / RJ, using a geoecological approach. For this purpose, several layers of functional and structures as shape in 1:10.000 scale, Digital Elevation Model (DEM), aspect, geomorphology and solar radiation was introduced through an analytical-integrative approach. All maps were 1:10.000 catastral maps from Pereira Passos Institute - IPP. The landuse was interpreted from 18 orthophotos in the same scale. Two geoecological susceptibility maps of fire, which show the susceptibility areas to fire occurrence in the Pedra Branca Massif have been generated. These maps were validated from the analysis of two burned areas identified, where the best adjusted map recognizes 93.8% of areas to fire. The susceptibility map developed presents susceptible fires areas and is expected to be used in strategic planning to combat wildfires.

Geoprocessing tools have been increasingly used to support the integrated study of geoecological variables, once they allow fast and efficient analysis. One of the products generated by geoprocessing of great importance do analysis that considerate the real surface of the terrain is the Digital Elevation Model (DEM). The consideration of the real surface is essential for the correct calculation of volumes, areas and distances, parameters of great importance for geomorfological indicators. There are many kinds of methods to generate this models and no consensus about which method has the best results, once it's precision will depend on characteristics of the study area. This work aims to compare the different DEM generation methods for irregular relief areas, using the Pedra Branca massif, RJ, as study area. It has been generated DEMs by two different interpolation methods and grids: one based in rectangular regular grid (TOPOGRID) and the interpolation method of Delaunay constrained, based in triangular irregular network (TIN), both generated in the software ArcGIS 9.2. For the verification of the quality and altimetric precision of these models, it has been utilized a map of declivities generated from the triangular irregular network model. Results show that the more adequate method for the study area is the TOPOGRID. However, it has been noted that this behavior is unequally distributed along its declivities classes, and it's errors are bigger in the great declivities, where the TIN model has been more efficient.

Landscape dynamics is a geoecological characteristic that defines changes in a landscape spatial structure and function during an established time scale. In this kind of analysis, geoprocessing is an essential tool, because it combines several technologies that help in this work. However, the majority of landscape dynamic investigations do not consider the dimensionality of the data and the information to be used, which is projected not measured from modeled (real) surface observations, and presents underestimated results, mainly in irregular relief landscapes. Considering that, this paper intends to assess the difference between observations on modeled and planimetric surfaces on the interpretation of landscape dynamics. The study was conducted in the massif of Tijuca, Rio de Janeiro (Brazil) using land use and soil cover maps of different times and a digital elevation models (DEM) generated based on a triangular irregular. The results show an increase of dynamic areas values when observations were carried out on modeled surface, as well as the deforestation rate (17.57% or 0.13 km²/year). This survey showed higher values in comparison with observations on planimetric surface, characterizing more realistic interpretations of how the structural elements and analyses made from these are structured in the landscape.

As análises ambientais de caráter integrativo vem sendo cada vez mais desenvolvidas nas últimas décadas com objetivo de refinar o conhecimento da paisagem. A Geoecologia apresenta dentro dos seus estudos a Cartografia Geoecológica que aliada às técnicas de geoprocessamento tem proporcionado importante contribuição para análises da paisagem. Uma aplicação da Cartografia Geoecológica é o mapa de potencialidade à ocorrência de incêndios, que é um produto da ação da própria paisagem (susceptibilidade) e do homem (risco). Este mapeamento apresenta proposições de alguns autores, entretanto, não há uma metodologia fechada sobre o tema. Neste sentido, o presente trabalho busca apresentar uma proposta metodológica sobre a temática, criando e testando um mapeamento de potencialidade à ocorrência de incêndios para o maciço da Pedra Branca/RJ. Este maciço apresenta um uso e cobertura bastante heterogêneo cujo principal característica é abrigar uma das florestas urbanas da Cidade do Rio de Janeiro, onde se situa um importante remanescente florestal do bioma Mata Atlântica. O mapeamento geoecológico foi avaliado em duas áreas de queimadas, e apontaram resultados satisfatórios. Além disso, outros dados de incêndios corroboraram com a validação positiva da metodologia e do mapeamento realizado.