In Belgium, forests cover nearly 7000 square kilometer and 80% of these forests are in the Walloon Region. Deciduous and coniferous species are well balanced and covered each almost half of the area. To anticipate the effects of climate change on Belgian forest ecosystems, various scientific studies have been launched in the course of the past decade. The results show that increasing CO2 concentration in the atmosphere will accelerate forest growth. However, in the medium-term, this growth will be limited by soil fertility and by the relative drought caused by higher temperatures and precipitation changes. Some conifers, the spruce for example, will become increasingly less suited to the climate in particular because of milder, rainy winters. In time, a broad-leaved tree such as beech could also become ill suited to the climate due to periods of drought.
In Brussels Region, the Forêt de Soignes/ Zoniënwoud is particularly vulnerable to climate change, considering that its main varieties (beech tree and summer oak) are particularly sensitive to droughts. The prospects for their preservation are not optimistic. The forest is a particularly interesting case due to its proximity to a large city that generates specific disturbances (intensity of atmospheric pollution, density of human visitors, etc.).
It is obvious that forests will undergo changes, at times significant, in species composition.
The Walloon Forest Code of 2008 advocates a mixed-species, mixed-age forest, adapted to climate change and able to mitigate certain effects. Forestry practices must therefore try to favour the species best adapted to (present-day) local conditions, which constitutes a first step towards adaptation to future changes. Species diversification and conservation of ecosystems that have remained relatively unaltered by human activity also enhance the forests’ capacity to adapt to changes. Among the measures outlined within the Forest Code are the retention of dead or fallen trees, the retention of at least one tree of biological interest per 2-hectare area and the introduction of integrated forest reserves in broad-leaved stands. Moreover, in order to improve the resilience of the forest ecosystem, we should encourage complex forest structures, ensure that soil fertility is maintained, manage water resources optimally (enhance soil and groundwater recharge by maintaining good soil structure and limiting the water consumption of the ecosystem through our choice of species and forestry practices), monitoring the density of game populations and correcting imbalances by means of amendments to situations requiring a response. Such provisions also apply in the Brussels-Capital Region.
In the Walloon region, a group of experts is studying the impacts of climate change in forest ecosystems. This group has produced a document containing recommendations for policy makers and a good practice guide for forest managers. As stated above, the spruce a tree widespread in Wallonia is highly vulnerable according to the climatic projections. Consequently, a new norm has been approved in 2009 to adapt the forestry practices of this species related to global changes (including climate change).
The Walloon Observatory of Forest Health was inaugurated in April 2011. This observatory was set up to assess and monitor the health of the forest throughout the territory, at both the short and long terms. It has 4 missions: 1) to produce a periodic assessment of the health of the forests, 2) to maintain data up to date regarding the development of diseases and pathogens, 3) to participate in the elaboration of maps of biotic and abiotic risks based on the vulnerability of the forest species and the stations, and 4) to compile the knowledge needed to set up a coordinated struggle in case of sanitary crisis. Partnerships have been set up with the Brussels Region and France to facilitate the exchange of data in real time when diseases appear and to allow a concerted management at interregional scale.
The evolution of its beech trees and oaks in the Forêt de Soignes/Zoniënwoud is monitored thanks to a permanent inventory of their condition. The inventories revealed signs that the forest was dying. The Region will adopt the forest management plan to preserve or improve its regenerative capacity and adaptation to environmental change. In the framework of the research programme “Science for a Sustainable Development – SSD” managed by the Federal Science Policy Office (BELSPO), the research project ECORISK “A decision support tool to manage climate change risks to forest ecosystems” (2012-2016) aimed to generate a decision support tool to analyse risks to forest ecosystems and forest responses as a result of extreme climate events, with a focus on addressing long-term effects on water, carbon and nutrient cycling in Belgian forest ecosystems.