Sustainable forest management in peatlands

Around a quarter of Finnish forests grow on peatland, which means that peatland forests play an important role as a source of income for forest owners and as a source of wood for industry. This page offers a collection of key tips on peatland forest management.

Felling income from peatlands is often smaller than that from heath forests, while forest management costs are higher. In addition, the risk of greenhouse gas emissions and emissions into waterways is higher than in heath forests.

Measures carried out in peatlands must be carefully planned, taking many perspectives into account, so that the forest owner can choose the measures based on their own goals. At Metsä Group, we develop peatland forest management to ensure profitable forestry operations and to minimise their adverse effects on the climate and waterbodies.

Opt for continuous cover forestry

In continuous cover forestry, only part of the trees are harvested each time. It is ideal for peatlands, and reduces peatland greenhouse gas emissions and waterway impacts.

A stable water level is essential in the management of peatland forests. When only some of the trees are harvested from a peatland forest at a time, transpiration continues through the remaining trees. The water level remains optimal, reducing greenhouse gas emissions and the impact on waterways.

In continuous cover forestry, the income from harvesting is lower per harvest than that earned from regeneration felling, but savings are made in planting and young stand management costs.

Continuous cover forestry is especially suitable for lush peatlands because there its positive effects are the greatest. We also recommend continuous cover forestry for lush peatlands in the proposed measures in forest plans in Metsäverkko.

Manage peatland forests with the Metsä Group Plus model

Learn more about the wood sale-specific Metsä Group Plus management model. In Metsä Group Plus harvesting of drained lush spruce-dominated peatlands, owner-members can get an additional bonus for felling when continuous cover methods – group selection or selection cutting – are used instead of clear cutting, and drainage ditches are not repaired in connection with felling.

Aiming for an optimal water level

An optimal water level is important both tree growth and reducing climate and water emissions. For trees, it is enough that most of the roots are above the water level. If the water level rises, tree growth suffers, the wet peat releases climate-warming methane, and the humus starts to move. If the water level sinks lower, the drying peat breaks down and releases carbon dioxide, which warms the climate.

The best time to check the water level is late summer. An optimal water level is 30–40 centimetres below the peat surface. This ensures that the tree roots are mainly above water, and their growth is not hampered by water.

An illustration showing the appropriate water level in peatland forests.

More tips for peatland forest management

A fertilised forest grows and evaporates water

A fertilised forest grows and evaporates water

While peatlands by nature often contain large amounts of nitrogen, trees are unable to use it due to the lack of phosphorus and potassium. Phosphorus and potassium can be added to the soil by ash fertilisation, which can give the trees a growth boost lasting decades.

As fertilisation improves forest growth, even more water evaporates through the trees, which helps keep the water level optimal. In this case, ditch repair may be unnecessary. This further reduces the flow of nutrients into ditches, the environment and waterways.
Drainage repair only when absolutely necessary

Drainage repair only when absolutely necessary

Drainage repair means opening old overgrown ditches. We do not repair ditches in mires whose water regime is in a natural or natural-like state. Drainage repair should not be done merely out of habit; the need should be carefully considered. Over-draining does not improve forest growth, but it does increase carbon dioxide emissions as the peat decomposes. It is also worth considering whether an excessively high water level could be corrected by ash fertilisation or continuous cover forestry instead of ditch repair, for example.

In regeneration felling, which results in the removal of most of the transpiring trees, at least partial drainage repair is often required. Repairs are needed if the water remains standing in the ditches, close to the peat surface, during the driest time in the late summer. It is often enough to repair only part of the ditch network.
Low-yield peatlands excluded from forestry

Low-yield peatlands excluded from forestry

Restoration, which means leaving the forest in a natural state, is an option in forests of stunted growth that remain waterlogged even after drainage. In practice, the forest is left to become waterlogged again and gradually return to its original state. The restoration process can be accelerated by removing all or some of the sturdy trees.

For representative sites, active restoration or conservation measures may be considered through the Metso or Helmi programmes, for example.

Opt for continuous cover forestry

See also

Manage peatland forests with the Metsä Group Plus model

Aiming for an optimal water level

More tips for peatland forest management

A fertilised forest grows and evaporates water

Drainage repair only when absolutely necessary

Low-yield peatlands excluded from forestry