Diagnóstico ambiental e paisagístico da arborização urbana do bairro centro de Santiago/RS

Abstract

In order to not cause any damages to the environment, planning the urban forestry is essential for urban development. The quality of the urban forestry is a determinant factor for environmental health, once it has a direct influence on our welfare. It also contributes for the climate stabilization, beautifies the environment and provides shelter and food to the fauna, generating shadow and leisure areas too. The research took place at the central zone of Santiago city, where it was made a survey about all local tree species found in the main streets and squares. Every tree was individually identified. The data were collected from December 2007 to February 2008, by in loco visits. Readings were made regarding to capacity, spatial distribution, intensity, diversity, uniformity, abundance and similarity between trees. In order to perform the geoprocessing, the information generated in the application AutoCAD was transferred to the software ARCVIEW®. The landscape analysis of the public squares was performed according to landscape architecture parameters. It was found a total of 3,123 trees, distributed in 117 species and classified in 45 families. Ligustrum lucidum, Lagerstroemia indica and Melia azedarach were the most frequent species. It was verified a predominance of exotic species, representing 73% from the total number. The specimens do not exhibit an uniform spatial distribution, having an isolated distribution, which is of the grouped type. It was noticed a variation in the density of trees at the sampling area. The value of diversity was equal to 3,29 (H ) nats/ind and uniformity (J ) was 0.71 nats/ind. The abundance index was equal to 85,9 trees/km of street while the Jaccard similarity coefficient was 0,125. Besides, 28,08% from the total of species are considered potentially toxic. The sum of individuals out of the planting pattern below the electrical grid represents 37,26% from the total of individuals. Regarding to the public squares, it was noticed a predominance of large-sized species, with tops that intersect each other, as well as an agglomeration of trees. Because of these characteristics it s necessary to occur a revitalization process of those trees and squares, aiming at turning these public spaces into leisure areas with a better environmental quality for the population. The urban forestry in the central area of Santiago city shows several problems, making necessary the gradual replacement of the most problematic species by other species that must be more adequate to the urban conditions.