The urban environment induces stress on trees and its impact can be identified by observing the condition of the crown. The aim of this study is to correlate the variables of crown density (Cdn), crown transparency (Ctr) and dieback (Cdie) with the following vegetation indices: the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), blue-normalized difference vegetation index (BNDVI), green-normalized difference vegetation index (GNDVI), green–red vegetation index (GRVI) and red–green–blue vegetation index (RGBVI) of the crowns of trees located in urban green areas, as well as chlorophyll fluorescence (Fv/Fm) as an indirect indicator of the overall tree health condition. A total of 549 trees were evaluated, represented in 24 families, 36 genera and 53 species; the variables had average values of 67.96% for Cdn, 35.19% for Ctr and 1% for Cdie. Correlations were found between Fv/Fm, NDVI and BNDVI. NDVI and BNDVI correlated with variables such as Cdn and Ctr, mainly in species such as Ligustrum lucidum, Jacaranda mimosifolia and Fraxinus uhdei. Therefore, it is possible to evaluate the tree health condition of trees in urban green environments through the identification of unfavorable conditions at the crown level by using vegetation indices for some of the species studied.

Locating potential tree-planting sites and analyzing tree canopy cover is important in the planning and management of urban forests. This paper reports the quantification of potential planting sites as well as tree canopy cover in the urban area of Mexico City, estimated by means of SPOT (Satellite Pour l’Observation de la Terre) 6 satellite images and a supervised pixel-based classification approach. Results showed an estimated area of 3100.7 ha of potentially useful sites, including places with bare soil and grass-covered areas such as median strips, roundabouts and parks. An average tree canopy cover of 10.6% and an average impervious surface of 79.2% for the 15 boroughs were also analyzed. The area of potential planting sites would represent a 5% gain for the current tree canopy cover if it were to be planted. With an overall accuracy of 92.4%, the use of both images from the SPOT 6 sensor and the classification approach proved to be appropriate for obtaining thematic covers in the urban environment of Mexico City.

El objetivo fue conocer la estructura, diversidad y los servicios ecosistémicos del arbolado en cuatro parques de la ciudad de Texcoco de Mora, Estado de México. Se realizó un censo y análisis de los árboles existentes en las áreas verdes seleccionadas. Se determinó una población arbórea compuesta por 391 individuos, pertenecientes a 19 familias y 34 especies. Los taxones más comunes fueron Ficus benjamina (23 %), Schinus molle (13.8 %), Hesperocyparis lusitanica (10.2 %) y Ligustrum lucidum (10 %). El índice de Simpson (1-D) presentó un valor de 0.73 y el índice de Shannon-Wiener H’= 3.89, lo que indica una alta diversidad. Las tres especies más abundantes sobrepasan la regla de diversidad 10-20-30 de Santamour. Se estimaron tres servicios ecosistémicos principales a través del software i-Tree Eco v6: almacén de C, captura de C y producción de O2. El arbolado evaluado almacenó 28.85 Mg C ha-1, capturó 2.56 Mg C año-1 y produjo un total de 6 Mg O2 año-1. Además de lo anterior, se calculó que los árboles removieron un total de 0.06 Mg año-1 de contaminantes y contribuyeron a reducir la escorrentía del agua de lluvia en 107.9 m3 año-1. La información generada es útil para la administración y conservación del recurso arbóreo, así como en la valoración del arbolado de la ciudad de Texcoco.