Restoring afforested peat bogs: results of current research

The value of peat bogs as open habitats and stores of carbon may be lost if they are planted with trees. The number of bogs being restored is increasing but still modest in scale relative to the area of afforested peatland. Research is currently being carried out to determine the feasibility and methodology for restoring afforested bogs. Two experiments were set up to compare a range of methods for managing trees and drainage. In the blanket bog experiment, treatments that involved both felling trees and damming plough furrows were more successful than others in terms of raising the water table. Bog vegetation recovered rapidly in the felled treatments, particularly those with furrows dammed. In the lowland raised bog experiment, the water table rose dramatically in all treatments. Only during a prolonged dry summer was there a difference between treatments, the water table falling deeper in the whole-tree removal than in the fell-to-waste treatment, with conventional harvesting intermediate. Bog vegetation recovered best in the whole-tree removal treatments and least well in the fell-to-waste treatments. Felling is necessary for restoring afforested bogs, but removing lop and top is not. Damming plough furrows can help to restore blanket bog but damming main drains may suffice on lowland raised bogs. Damming furrows is ineffective if the peat is severely cracked. Tree seedlings often colonise bogs undergoing restoration – removing brash mats after harvesting and periodic maintenance should reduce this problem.