Detection of Spatio-Temporal Changes of Norway Spruce Forest Stands in Ore Mountains Using Airborne Hyperspectral Imagery

Ore Mountains (west of the Czech republic) are an example of the area that suffered from severe environmental pollution originating in coal mining and heavy industry leading to massive dieback of the local Norway spruce forests between 1970’ and 1990’. The situation became getting better at the end of 1990’ after significant decrease of pollution loads. In 1998, ASAS airborne hyperspectral data were used to study the health status of the Norway spruce forests in this area. New hyperspectral data acquisition (APEX) was organized in 2013. Therefore there is a unique opportunity to study recovery of the originally damaged forest stands and compare them with the stands that have been less affected by environmental pollution. The analysis was conducted assessing a set of 16 vegetation indices to provide complex information on vegetation foliage biochemistry, canopy biophysics and structure. Five of them (NDVI, NDVI₇₀₅, VOG₁, MSR and TCARI/OSAVI) showing the best results were employed to study their spatial gradients as well as temporal changes. The obtained results indicate that the original significant differences between the damaged and undamaged stands have been generally levelled until 2013, although it is still possible to detect some signs of the previous damages in several cases.