The latest data from the Observatoire Wallon de la Santé des Forêts [Walloon Forest Health Observatory] (OWSF) show that this affects almost all forest species, with the exception of poplars, chestnuts and hornbeam. On the other hand, species such as ash and spruce are in such poor condition that they are regarded as a cause for concern.
The most plausible hypothesis for this fragile condition seems to be that it results from years of drought, which has had a negative impact on the availability of water. The increased temperatures observed in recent decades have also had the effect of lengthening the growing season (with a resulting impact on the access to water for trees), and facilitating the development and proliferation of pathogenic fungi and pestilent insects.
The CARTOFOR project is responding to this problem by developing methods for monitoring the state of health of forest stands consisting of ash, Douglas fir, larch, beech and spruce using multispectral and aerial satellite imaging. The approach is based on a wide range of field data collected by our partners (Gembloux ABT, UCLouvain, OWSF, DEMNA, DNF) over many years.
Depending on the species and the nature of the decline, the approach adopted is focused at the level of an individual tree (ash, beech) and/or the stand (Douglas fir, larch, beech, spruce).
While convincing results are already available, the soon-to-be-available hyperspectral satellite images should make it possible to supplement and improve the current CARTOFOR approach and lead to the implementation of an operational monitoring and alerting system (diseases, drought, fire, etc.) for Walloon forests.
This system can be easily integrated into the Système d’Information des Forêts en Europe [Forest Information System in Europe] (FISE), which is currently being set up as part of the new EU strategy for forests by 2030. This new strategy includes measures aimed at bolstering the protection and restoration of forests, and improving the sustainability of forest management. Monitoring and the efficient and decentralised planning of forests in the EU will help maintain the resilience of forest ecosystems and enable forests to fulfil their multifunctional role.
Funding: Project subsidised by the SPW, grant No. C2U06.LX3201.