240 street urban forest for Campinas was calcu- lated using the presence of sidewalk trees, as foreseen in law of Campinas urban forest number 11,571/2003 (Campinas 2003): one tree at every 10 m. The optimal number of trees on sidewalks, calculated for the urban area, was 486,318; therefore, according to these results, there is a deficit of 365,588 trees. DISCUSSION The method used was faster than a field census. Together, the image census and the field validation took 90 hours, whereas a census made ex- clusively at the field level would have taken 1,500 hours, both using a team of four peo- ple. The data obtained were accurate enough (Table 1) to estimate the real number of trees. Qualified management of street trees, espe- cially those on sidewalks, splitter islands, and roundabouts, depends on the analysis of the spacing for trees and the number of inhabit- ants of each neighborhood (Figure 5). As urban densification increases, commerce expands, and the car fleet increases. As a result, build- ings advance towards the sidewalks, which are lowered, and the streets expand, thus reducing the space necessary for the trees. This is the case of the downtown area, with sparse street trees, and featuring the small amount of six trees per kilometer (Figure 4). Historically, the City of Campinas has had an excellent history of urban forestry with abun- dant species diversity and medium- or large- sized individual trees providing better ecological benefits. However, today the city is not different from any other metropolis. With urban sprawl, greenspaces diminish, including street trees. The rapid deployment of condominiums and build- ing lots that do not faithfully obey the laws of land use and occupation result in the reduc- tion of greenspaces. Santin (1999) pointed out that the government has not been taking the proper care on the approval of new condos, thus undermining the distribution of vegetation. On the other hand, Campinas is renowned for the presence of a forest reserve within the urban area, the Santa Genebra Forest, as well as of some other native fragments within and near the urban area. These elements are essen- ©2015 International Society of Arboriculture Alvarez et al.: Street Tree Inventory of Campinas, Brazil tial to the city’s microclimate, but they depend on the city’s surroundings for the mainte- nance of the biodiversity and for a decrease in the border effect. In this case, the street trees can be used as a way to deploy ecological cor- ridors and connect those fragments among themselves, allowing the gene flow of species. Studies on the street tree urban forest have aimed to diagnose the trees at the field level (Jim 2008; Nowak et al. 2008), in order to compose a future qualitative inventory. The cost of these initiatives to city halls has been high. In Brazil, few cities have man- aged to complete this work, and/or when they completed it, the data were already outdated due to the dynamics of urban vegetation. The data presented here are ready to be used for management purposes (Figure 6). It is possible to segment the planning deficit by location, for example, if there is a neighbor- hood association mobilized for tree planting. When compared to other works that per- formed field surveys, the sampling error here was smaller. Alvarez et al. (2005) found the following errors when estimating the total tree population, both for the random and the stratified sampling, when compared to the census: 17.32 and 37.05, respectively. Nowak et al. (2008) estimated the number of trees in 14 North American cities and found relative error rates from 8.1% for Atlanta, Georgia, U.S., up to 19.2% for Baltimore, Maryland; in both cases, stratified random sampling was used. The tree distribution in the urban area of Campinas is very uneven as a whole. The total number of trees for the city was 24.8 trees/km, which is low when compared to Melbourne, Australia’s 64.71 trees/km (Frank et al. 2006). These numbers are 25% lower than they should be. However, when researchers examine them neighborhood by neighborhood, some places were detected to already have important green spaces and a significant number of street trees, such as the Cidade Universitária neighborhood (49 trees/km). However, in other locations, such as Campo Grande/Jardim Florence, there is a complete lack of greenspaces, and there are many blocks without a single tree, with an average of 8 trees/km, which is only 8% of the ideal amount.
September 2015
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