In peatlands, carry out drainage repair only if tree growth is hampered by excess water, and the trees have clearly benefited from prior drainage. Ditch network maintenance lowers the water level in peatlands. This leaves more peat in aerobic conditions above the water level. In aerobic conditions, peat decomposes, releasing carbon dioxide into the atmosphere. You can protect the carbon storage of peatlands by refraining from unnecessary drainage.
Although ditch network maintenance is one of the most important forestry measures in peatlands, it is not always necessary, even in drained bogs. If the water level is too high, it can often be corrected through fertilisation or continuous cover forestry, for example.
If the benefit from prior drainage has remained insignificant, ditch network maintenance will not be worthwhile. Avoiding unnecessary drainage repair is also important for the protection of waterways.
However, if drainage repair is deemed necessary, try to avoid making the drains too deep. The trees benefit most when the water level drops to a depth of 35–40 centimetres. A lower water level will not improve tree growth, but may increase carbon and nutrient emissions.
We revised our guidelines for peatland management in 2020. Read more about them here.