Assessing urban habitat quality using spectral characteristics of Tilia leaves

Monitoring environmental quality in urban areas is an important issue offering possibilities to control and improve urban habitat quality as well as to avoid adverse effects on human health. A tree leaf reflectance-based bio-monitoring method was used to assess the urban habitat quality of two contrasting habitat classes in the city of Gent (Belgium). As test trees, two Tilia species were selected. Custom made Matlab code is applied to process the measurements of leaf reflectance. This enables the discrimination between polluted and less polluted habitats. The results elicit, that leaf reflectance in the PAR range, as well as the NDAI (Normalised Difference Asymmetry index) are species dependent while Dorsiventral Leaf Reflectance Correlation (DLRC) seems to be independent of species. Therefore the assessment of urban habitat quality is perfectly feasible using leaf reflectance, when taking account of the species specificity of tree leaf physiological and structural responses to habitat quality.