Vegetation survival and condition in public green spaces after their establishment: evidence from a semi-arid metropolis.

Abstract

Urban vegetation is generally exposed to adverse environmental conditions, such as high temperatures, compacted soils, low fertility, and a high pollutant concentration. The influence of biophysical and social factors on the survival and condition of trees and nontrees was analyzed using a census of plants in 37 green spaces of the Metropolitan Region of Santiago de Chile (MRS) several years after their establishment. The tree survival rate was higher (77%) than that of other species (24%). Survival was primarily explained by municipality management and species selection, but the relevance of these factors differed between trees and nontrees. Species with low water requirements outperformed species that were more sensitive to water stress. A high mechanical damage rate was observed, with 91% of trees showing severe or medium damage. Soil quality was better than expected, with a bulk density less than 1.0 g m-3 and moderate and high levels of P, and only 8% of sites had low K levels. The N content was highly variable, but most of the sites had levels greater than 20 mg kg-1, which indicates a trend of accumulation that is consistent with urban soils. More in-depth studies are required to establish the factors that explain plant survival in public spaces of the AMS, and irrigation monitoring is especially needed.