Resumo

SAAVEDRA-ROMERO, Luz de Lourdes et al. Crown condition, a health indicator in urban trees of the San Juan de Aragon Park, Mexico City. Madera bosques [online]. 2016, vol.22, n.2, pp.15-27. ISSN 2448-7597.  https://doi.org/10.21829/myb.2016.2221321.

Green urban areas provide several benefits to society and to the environment. San Juan de Aragon Park, located in the northeast of Mexico City, is one of the few green areas in that urban zone but the health of its trees is not known. In this survey, the crown condition indicator protocol was adapted and applied in 28 circular plots (0.1 ha) established randomly in this park. Normal diameter, total height, species identity, crown condition and tree density were evaluated for all of the trees within these plots. Six crown variables were measured: live crown ratio (Lcr), crown density (Cdn), crown transparency (Ctr), crown dieback (Cdie), crown position (Cpo) and light exposure (Lex). The first four variables were measured in 5% classes, and the latter two by using an ordinal scale. A total of 760 trees, grouped into 10 families, 11 genera and 12 species, were evaluated. The average values for the crown variables were 56.37% for Lcr, 44.38% for Cdn, 4.04% for Cdie and 38.4% for Ctr. Only Lcr reached the standards established in other studies, while Cdn was lower and Ctr and Cdie were both higher.

Palavras-chave : green urban areas; crown dieback; live crown ratio; crown transparency.

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