Proportions of Green Area and Tree Health on University Campus: The Impact of Pavement Presence

Abstract

Sustainable urban ecosystems require healthy green spaces that provide ecological services to meet social and environmental needs. This study evaluates the proportion of green areas in the urban campus and assesses the effects of pavement on the health of Samanea saman. The MAPIR Normalised Difference Vegetation Index (NDVI) camera mounted on a drone captured a proportion of green areas of approximately 27.80%, which is roughly a quarter of the total study sites. However, the significance of green areas depends on the health of the trees. Therefore, the pavement effects on the health status of trees in green areas were studied using Visual Tree Assessment (VTA) and aerial image analysis using the MAPIR (NDVI) camera on a drone. Although both methods evaluate health status, the final outputs differed. VTA produced categorical outputs, which assigned trees into health categories based on a visual assessment of factors. In contrast, NDVI produced linear outputs, which provided a numerical value to demonstrate tree health. Both methods indicate that trees in non-paved areas are healthier, particularly for the excellent trees identified by the VTA, which suggests that pavement negatively impacts tree health. However, the effects of paved and non-paved areas on tree health status analysis using the aerial image are not significant (p>0.05), which may be due to the low quality and accuracy of the images. The study provides insights into the importance of green areas and tree health in creating sustainable urban ecosystems.