Towards greener cities; investigating the potentials of vertical greening in tropics as a design approach to create sustainable urban environments

Abstract

The rapid population acceleration and urbanization pressurize the need of more living places leading to considerably high artificial constructed structures and comparatively less vegetation. Vertical greening is identified and implemented as an interesting integration in improving urban environmental quality and life standards. Energy saving, influencing biodiversity, noise attenuation and many more benefits are associated with the vertical greening. In Sri Lankan context the practice of vertical greening is still at an initial stage and the knowledge on the system is very limited. The paper presents the results of experimental design conducted to identify plant performance to select a plant species for vertical greening in local context. Twelve plant species were selected for the study. Plant health was rated for all plants using a 3 point scale. 1 = thriving, 2 = alive, but with signs of pest, disease or other stresses, 3 = dead. Plant height and leaf area were measured along with visual assessments of plant development stages and pest/disease incidence. Temperature reduction was measured for selected species. Inter-species variations were identified using one-way ANOVA followed by Tukey's pairwise comparison. In terms of actual performance, Roheo spathacea, Axonopus compressus, Ophiopogon japonicus, Axonopus fissifolius displayed the greatest survival and coverage on an extensive green wall. Highest LAI obtained from Roheo spathacea (3.99) followed by Axonopus compressus (0.99) over the trial period.