Processos de transformação da estrutura verde do Porto

• Autor(a) principal: Helena Madureira
• Data de Publicação: 2001
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: https://hdl.handle.net/10216/76339
• topic: Ecologia humana, Geografia, Outras ciências sociais; Human ecology, Geography, Other social sciences

The presence of a vegetal coverage in cities cannot be a mere residual conse-quence of urban planning. The relevance of the functions it performs as an envi-ronmental amenity, as leisure support and as one of the essential components of urban morphology requires a perspective of intervention aiming to enhance those functions on the urban tissue. With the present thesis we want to carry a reflection on the evolution of the green structure in urban areas, centring the analysis in the specific case of Oporto, con-sidering those three functions we think fundamental. We have focused our analysis, essentially, on the confrontation of two time landmarks, the final years of the nineteenth century, when Oporto urban structure reflect the first changes decurrent of the Industrial Revolution, and present days, the final of the twentieth century, when the city overcomes its administrative limits evolving to a metropolitan structure. Recognising that urban green structure on its multiple functions - environmental, recreative and formal - we thought it would be imprescindable the full perception of Oporto green spaces on those two time landmarks. Using the «Carta Topographica da Cidade do Porto» draw by A.G. Telles Ferreira (1892) and the orthophotomaps of Oporto (pages 122 I-IV, Instituto Geográfico do Exército, 1995), we proceeded to the full digitalisation of what we consider to be the different typologies of green urban structure: agricultural spaces, arborized spaces, green spaces associated to edification, public gardens and parks, arborized streets and cemeteries. The construction of these two cartographic bases allowed us to confront the Oporto's green structure on those two historical contexts, inducing the search of the main explanative processes of its transformation. On the end of the nineteenth century Oporto already reflected the urban develop-ment induced by the industrialisation but nevertheless was still a city profoundly «green». Green on the enormous rural belt that surrounded its small urban spot, green on the interior of the neighbourhoods of its new expansions, green on the non negligeable number of public gardens that served the city. A context well different of the one found in 1995. The diminution of the available green in the city is flagrant. If one century ago the green occupied more than 75% of the territory surface (3.044 ha), actually it occupies less than 30% (1.164 ha) of the same surface, representing one diminution of about 60%. The diminution of the green presence in the city constitutes one inevitable process when we know that one century ago the city was still not very urbanized and that it was on the twentieth century that the urbanised spot extended to all its territory. We do not put in ques-tion, therefore, the fatal diminution of the green associated to a desirable process of the urban development. The forms this urban development assumed - resulting mainly from an inefficient planning - and their repercussions on the green structure - which was seldom integrated on planning processes - is what, in our point of view, must be questioned, namely because they are responsible for one main characteristic of the present green structure: its high fragmentation and discontinuity.