Áreas verdes em Nova Iguaçu (RJ): a contribuição da vegetação aos espaços urbanos centrais da cidade

Abstract

Urban green areas are physical spaces that have tree or shrub vegetation, whether public or private, and act as reformulators of urban spaces by mitigating temperature, maintaining air humidity, reducing pollution and reducing albedo. In this way, this research aims to analyze the different green areas in three central neighborhoods in the municipality of Nova Iguaçu (RJ): the Luz, Centro and Caonze neighborhoods, and the influence that the Environmental Protection Area (APA) of the Gericinó-Mendanha Massif has on the respective neighborhoods. To achieve these objectives, different data collection tools and techniques were applied, such as processing satellite images to create thematic maps, using the Quantum GIS (QGIS) program, a Geographic Information Systems (GIS) software, to check how these green areas are spatially distributed in the neighborhoods. The Green Areas Index (IAV) was calculated using the formula adopted by Harder (2002), which consists of the sum of the total area in m² or km² of the types of trees present in the urban space, divided by the number of inhabitants. The calculation of the Vegetation Cover Index (VCI) was based on studies by Nucci and Cavalheiro (1999), which refers to the percentage of existing vegetation cover of each green area delimited on the maps. After checking the indices, we tried to measure the temperature in the sun and in the shade provided by the tree species at nine points, three in each neighborhood, in order to investigate the influence of tree vegetation on the temperature of the incident surfaces. A digital infrared thermometer with a laser sight (version 320-EN-00, Caution brand) was used to measure the temperature. With regard to the survey of the massif's geo-environmental characteristics, the aim was to analyze the conditions of land use and land cover, their influence on the quantification of green areas in the neighborhoods, as well as observing the topographical aspects and identifying the degree of deforestation along its edge. According to the data obtained, the ICV of the Luz and Caonze neighborhoods showed percentages above 30%, while the Centro neighborhood was below. For the IAV, these were not considered low, due to the population density. As for the results of the reflectance temperature measurements, there was no significant difference between the values found in the summer and winter periods, but when comparing vegetated and non-vegetated areas, the difference was remarkable, 39.1ºC between a point with massive vegetation and another without any type of vegetation cover. If we remove the role played by the Gericinó-Mendanha Massif in increasing these indices, we see a reduction of 24%, 8% and 17% respectively in the amount of green areas in the neighborhoods of Luz, Centro and Caonze. The green areas index acts as a socio-environmental indicator that improves the urban, environmental and life quality of the population. In an urban environment, it should be noted that the most significant factors for cooling are the presence of vegetation. For this reason, the provision of a green system that permeates the urban fabric is essential for comfort and quality of life in cities.