Tree diversity and structure on green space of urban and peri-urban zones: The case of Lubumbashi City in the Democratic Republic of Congo

Abstract

Urbanisation generally causes a number of ecological problems, mostly associated with loss or degradation of green spaces. In the city of Lubumbashi (Democratic Republic of Congo), not only the health of the local vegetation has been profoundly affected due to an accelerated and uncontrolled spatial dynamics, but decision-makers and planners are also short of data likely to maximise the environmental benefits provided by woody green spaces. Hence, this study was designed to characterize the plant diversity and structure of woody green spaces in Lubumbashi. The study area was divided into urban and peri-urban zones, with respect to the urbanisation level, and data were collected utilising a circular plots-based inventory. Sixty species of trees and shrubs, belonging to 22 families, were recorded. The considered woody green spaces are dominated by miombo woodland species, but Acacia auriculiformis remained the most common species. This study suggest the existence of tree and shrub species that are typical of the urban zone and the peri-urban zone. Comparatively however, the average diameter and the basal area of trees were significantly higher in the urban woody green spaces, which seems to suggest more old trees in urban zone. Both urban and peri-urban zones had a reverse-J-shaped size class profile, with a slight jump in the largest size class. The peri-urban woody green space had more small stems, but not markedly so, and recruitment was observed in both zones. Current results are important as they may in formulating guidelines and technical tools in assessing and monitoring the degradation of woody green spaces in the city of Lubumbashi.