Impact of time scale on plantation pattern: an approach to access tree diversity changes in urban parks

Abstract

Urban parks are an important part of the city's green infrastructure and serve as an indicator for the city's natural environment. Six urban parks in Faisalabad were evaluated, split into two categories: Old parks (OP) and New parks (NP). A thorough census of tree populations was conducted in specified urban parks, and many parameters were studied. The composition of trees, species richness, and distribution of native and exotic trees were evaluated among two types of parks. Tree stem count was used to calculate the diversity benchmark (10/20/30) for tree inventories in selected urban parks. The major objective of the study was to determine the difference in species richness and diversity indices of selected urban parks in both categories. Evaluation of the plantation of Urban parks on the basis of the proposed benchmark (10/20/30) was also the key objective of the present study. The results revealed that 2978 trees from 52 species, 45 genera, and 22 families had been counted, with 2004 trees in the OP and 794 in the NP. A few common species hold the majority of the distribution. OP have higher share of native trees (67.07%) while NP have higher share of exotic trees (59.32%). The dominance of exotic tree species in NP depicted that change in time has significantly affected the plantation pattern of urban parks in Faisalabad. OP had higher tree species richness (47) as compared to NP (36). The dominance of exotic species in new parks is the major cause of low tree diversity. Results of the tested benchmark indicated that the plantation of selected urban parks approximately failed to achieve the proposed diversity benchmark. In urban parks, more attention should be paid to the plantation design and species selection. The pressing need of the hour is to have a tree mix that promotes biodiversity while also maximizing ecological services