The potentials and limits of monitoring forest traits with imaging spectroscopy
Proposers: Michael Förster, Fabian Fassnacht, Henning Buddenbaum
Although there is a long history of utilizing spectral measurements of forests, there might be no other application field where the uncertainties about the real potentials of imaging spectroscopy are larger. It is not even certain that the most basic information, which is tree species, can be detected in full detail. With respect to some other variables such as biophysical forest traits and forest health, some studies seem to solve long-standing challenges like the early detection of calamities or chlorophyll content with high accuracy. However, other investigations struggle to replicate these results. These uncertainties have their origin in the structural complexity of the ecosystem as well as in the size of trees, which makes it complicated to have repeated, standardized and comparable in-situ measurements. This leads to a patchwork of often small and experimental datasets which cause widely differing results.
This is especially problematic since there currently is a strong need for a structured and systematic Earth observation approach of forests across large areas, especially regarding their health. As a response to the extreme hot and dry years 2018 to 2020 almost all important tree species of Central Europe showed severe signs of drought stress and forest die-off was observed over large areas. Therefore, both methods that create knowledge on the extent of the damage (including dead and damaged trees) as well as approaches for early-detection of drought stress are highly demanded. Therefore, we are happy to suggest a special session on the application of imaging spectroscopy to estimate and map forest traits. We are especially interested in studies that show potentials and limits of imaging spectroscopy approaches in forests. Encouraged are submissions applying hyperspectral information alone or in combination with other data types to derive a wide range of tree and forest parameters. The latter include species information, biochemical and biophysical traits as well as the health status of trees.
Some interaction with the audience is planned as part of this session by inviting presenters and members of the EARSeL community to formulate the main achievements of Imaging Spectroscopy in the field of Forestry over the last ten years as well as the main future challenges for the next ten. According to the suggested topics, we will ask all participants about their opinions / experiences to shape the potentials and limits – particularly also with respect to existing and future satellite missions.