Desenvolvimento de um método de avaliação monetária de árvores urbanas e aplicação à situação de Maringá - PR

O presente trabalho objetivou estabelecer um metodo de avaliacao monetaria de arvores individuais, componentes da arborizacao urbana, baseado nos custos de manutencao das arvores de rua de Maringa. Com cerca de 240.000 habitantes (1991), Maringa possuia em 1988 aproximadamente 62.818 arvores de rua, responsaveis por 13,6 m2 de area verde por habitante. O municipio apresenta legislacao de protecao a arborizacao (Lei 2.585/89) que determina, aos causadores dos danos em arvores, o pagamento de indenizacao e multa com valores calculados em funcao da circunferencia do tronco (CAP) que se revelam de dificil aplicacao. Assim, com o apoio da Prefeitura Municipal de Maringa (PMM), foi elaborado um sistema de avaliacao monetaria de arvores urbanas que desse respaldo tecnico-economicas as penalizacoes e que levasse em conta as operacoes de implantacao e manutencao da arborizacao. Os dados coletados sao referentes ao periodo de janeiro a junho de 1992. A elaboracao do metodo exigiu a determinacao dos custos medios de mudas, tendo por base os precos medios de aquisicao praticados pelas empresas privadas da regiao. As despesas realizadas pela administracao municipal influentes no custo da arborizacao, tais como, manutencao de pessoal, aquisicao de material de consumo e insumos, de bens duraveis e despesas administrativas, foram obtidas atraves da analise dos balancetes mensais da PMM para o periodo considerado. Foram computadas, ainda, as despesas geradas pela realizacao da poda pela Companhia Paranaense de Energia. O metodo, ora proposto, determina o valor da arvore atraves da aplicacao do custo da muda, por especie e da idade de plantio em uma equacao de primeiro grau formada por componentes relativos a custos correntes, custos de bem capital e custos administrativos, corrigidos por um fator referente a taxa de juros na idade considerada (6% ao ano). O principal limitante a aplicacao do metodo e que se faz necessario conhecer a idade de plantio da arvore a ser avaliada. No caso de Maringa, a estratificacao dos custos de mudas por especie nao se mostrou significativa, dai porque foram utilizados custos medios de mudas nas avaliacoes. Os valores das arvores entre 1 e 50 anos estabelecidos pelas formulas sao equivalentes a respectivamente US$ 60 e US$ 6.850. Monetary and public-awareness evaluation of urban forestry: methodological application to the situation in Maringa - PR Abstract This work aimed to establish a method of monetary evaluation of individual trees, components of urban tree planting, based on the cost of maintenance of Maringa’s street trees. With about 240,000 inhabitants (1991), Maringa possessed in 1988 approximately 62,818 urban trees, representing 13.6 m2 of green area per inhabitant. The municipality has a law protecting trees (Municipal Law 2,585/89), determining that those who cause damages to trees pay indemnity and fines in amounts calculated in relation to trunk circumference (CBH). Considering that the amounts stipulated by law are very high it is consequently difficult to enforce. Maringa Town Hall (PMM) decided to support the preparation of a system monetary evaluation of urban trees that would provide technical-economic backing to penalties, taking into account the planting and maintenance of trees. The data collected for the development of the monetary evaluation method encompass the period from January to July, 1992. The design of method demanded the setting of the average costs of seedlings, based on average purchasing prices practiced by the private trade in the region. The expenses incurred by Town Hall influencing tree-planting costs, such as staff maintenance, acquisition of consumables and fertilizers, durable goods and overheads, were obtained by the analysis of the monthly balance sheets of the period in question. Moreover, the expenses generated by the pruning made by the Parana Power Company (COPEL) were also taken into account. The method now processed determines the value of a tree by applying the cost of seedling, per species, and plant age to a linear equation formed by the components concerning current costs, capital goods costs and overheads, corrected by a factor related to the interest rate at the considered age (6% a year). The main limitation to the application of the method is that it is necessary to know de age of the tree under evaluation. In the case of Maringa, the stratification of the costs of seedlings per species did not show significance; therefore average costs of seedlings were employed in evaluations. The values of trees between 1 and 50 years of age, set by the formula, are equivalent to respectively US$ 60 and US$ 6,850.