Resumo

ZARAGOZA HERNANDEZ, Alejandra Yunuen et al. Crown condition indicator and its use in three parks of Mexico City. Rev. mex. de cienc. forestales [online]. 2014, vol.5, n.25, pp.34-51. ISSN 2007-1132.

The crown condition indicator estimates the proportion of trees that displays a crown dieback or a foliage density considered lower than normal or different from the natural shape of the tree. Usually, thick and large crowns relate to high growth rates while small ones suggest sites with unfavorable conditions for an appropriate development of the urban forest. Crown condition and its variables can provide reliable information to diagnose the urban trees' general health condition. The chosen sites were three parks within Mexico City known as Alameda Oriente, Alameda Norte and Alameda Sur. Three samplings were carried out during the rainy season (May to October 2011) and one during the dry season (November 2011 to April 2012). Variables registered were crown density (dnc), crown dieback (mr) and foliage transparency (trpf) as percentual increases (5 %) on a scale of 0 to 100. Normality tests, variance analysis and a non-parametric U Mann-Whitney and Kruskal-Wallis analysis were carried out. According to the results, trees within Alameda Oriente had better health status since they showed the highest values for the variable dnc and the lowest values for mr. On the other hand, trees within Alameda Norte showed the lowest values for the variable dnc and the highest values for mr, therefore, it has the poorest health condition of the tree parks that were evaluated.

Palavras-chave : Alamedas; crown condition; crown density; crown dieback; forest health; foliage transparency.

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