Based on the action plans for the wet and dry forest habitats to be created, RMK will restore 3,500 hectares of deciduous swamp forests and 500 hectares of dry forests during the project. The areas to be restored are selected by the forestry working group from the University of Tartu.
Although the aim of restoration is usually to improve the condition of the area, there are also exceptions: if the nature conservation value of a previously drained protected bog woodland is constantly declining due to a functioning drainage system, then restoration activities (closure of the drainage system) are necessary simply to maintain the condition of the area.
The forestry team from the University of Tartu selected the areas in need of restoration in several stages:
- initially, a pre-selection of core areas with deciduous swamp forests within Natura sites was carried out as a geo-information request;
- areas with a visually higher drainage impact were then selected from this set, where the closure of drainage ditches could improve the quality of wet deciduous forests;
- in the second stage, areas with a surface area of less than 20 hectares were removed from the generated sample: as a result, 64 areas were selected (with a total area of about 20,000 ha, the estimated area per site being 50–1,000 hectares per area);
- in the third stage, 12 factors related to these areas were assessed, such as the proportion of forest stands in the total area, the proportion of deciduous forests over 50 years of age out of all deciduous forests, the compactness of the drainage system to be closed, land ownership and protection-related questions, and the proportion of private land in the limited management zone. Existing factors could provide both positive (contributing to the success of the restoration) and negative points (factors limiting the success of the restoration or the risk of destruction of already existing values);
- in the fourth stage, the main problems involving the fields were clarified – the experts familiarised themselves with the past history of the areas, covered the wider surroundings, mapped the sites of protected bird species that may be sensitive to disturbances, and identified the form of ownership and protection status of the areas.
This left 17 areas for screening, which, in turn, are divided into seven priority groups.
Restoration process
The main goal of the restoration of a wet forest habitat is to reduce the impact of drainage, i.e. to close the ditches. Usually, one dam is not enough to close a ditch, as the high water would simply wash it away during wet periods. Therefore, several dams will be built on the ditch, or the ditch will be completely closed along its entire length using soil.
Soil works are usually carried out with an excavator. In order for such a large machine to move, it is usually necessary to remove trees from the targets along the ditch. This is one of the negative factors involved in restoration. Ditches can also be closed manually during the work, but it is difficult to find people to perform such large-scale shovel work. In certain instances, however, this has been done.
During the course of restoration or due to the changes that followed, the existing natural values of the area (rare species or established forest communities with old trees) may be damaged. Restoration is quite costly and leaves a significant climate footprint when using large machines. Therefore, restoration work is not carried out lightly; instead, areas are sought that have suffered damage from human activity to such an extent that natural restoration would take a long time.
Cost-effectiveness must also be monitored. For example, in a formed drained peatland forest, bog processes do not recover within a reasonable time, and in the case of elevated water levels, a large part of the established forest stand will probably be destroyed. Therefore, priority should be given in restoration to areas where the value of the wet forest habitat can be increased more effectively.
In both wet and dry forest habitats, restoration activities may include the thinning of forest stands and the shaping of a more natural composition of tree species, as well as the generation of dead wood. For example, in the case of dry forest habitats, such as forested dunes and coniferous forests located on eskers, formative cutting may be given consideration to preserve the habitats of the endangered species associated with them. Activities that promote the development of these habitats, such as weak surface fires or temporary light grazing, could also be maintained.
In most cases, the best way to maintain and improve the condition of a habitat is for people to not interfere any further with the natural development of the area.