Good forest management helps keep forests as carbon sinks

In Finland, active forest management has increased both the carbon sink and carbon storage of forests. Carbon storage has increased, because forests now have more wood than a hundred years ago, when the first national forest inventory was carried out. The carbon sink has also grown because our forests now grow better and more densely than before.

As a forest owner, you maintain the carbon sinks of forests by managing your forest well. The measures described on this page will help you to continue to look after your forest’s carbon sink.

Regenerate rapidly

In forest regeneration, speed is also an advantage for the enhancement of carbon sinks. The sooner you establish a new forest, the faster the trees can start sequestering carbon again. Replace a felled forest with a new one as quickly as possible to minimise the treeless and sparsely wooded phase. In the best case, a well-managed seedling stand in southern Finland becomes a carbon sink at the young age of 15. Good soil preparation, high-quality seedlings and seeds, as well as proper planting or sowing ensure that forest growth gets off to a flying start.

Use improved seeds and seedlings

In forest cultivation, it is best to favour improved seeds and seedlings, because they boost tree growth by as much as 20–30 per cent and result in trees of a better quality than those grown from natural forest material. This leads to considerably higher wood output and carbon sequestration per hectare. In addition, the longitudinal growth of improved seedlings is swift, quickly leading to the establishment of a stand and a new carbon sink.

Carry out or commission young stand management in time

Properly implemented young stand management helps seedlings quickly develop into a vibrant and resistant forest, with trees that sequester more and more carbon as they grow.

Thanks to young stand management, the best seedlings have more space to grow, and forest growth targets trees that will become high-quality logs in the future. The more log wood is obtained from the trees harvested during the rotation period, the more carbon is sequestered in high-quality and long-lived wood products. If logs are converted into sawn timber, used in wooden houses, for example, the carbon may remain sequestered in the end products for hundreds of years.

Leave at least ten per cent of broadleaved trees on the stand

A mix of broadleaved trees improves tree growth and boosts biodiversity. Forest biodiversity requires attention at all stages of forest management. Usually, some 1,800 spruce seedlings are planted per hectare of regeneration area. However, broadleaved seedlings also emerge there naturally, and by the time of early cleaning, the number of broadleaved seedlings may exceed 25,000 per hectare. The goal of young stand management should not be to obtain strictly single-species forests, but diverse forest stands that also offer protection and food for many different species.

Maintaining biodiversity is also in the forest owner’s interest. A 10–15 per cent silver birch mix in a stand of spruce seedlings not only increases biodiversity, but also the stand’s growth. In addition, broadleaved trees make the forest more resistant to damage. Damage by insects, storms and snow, for example, is expected to increase in the future, which is why a well-managed mixed forest is a sensible way to minimise risks and ensure that the forest remains a carbon sink.

Carry out thinning in time

Thinning means removing poor-quality and slowly growing trees to create growth space for high-quality trees. The remaining trees continue to grow and sequester carbon, and growth targets the best individuals, which grow faster and produce sturdy log wood.

First thinning in particular should not be delayed, because thin trees with tufty tops grow poorly, react slowly to thinning and are prone to damage. The timing of the subsequent thinning is less important than the first thinning. It is determined more by the forest’s management history and the forest owner’s goals.

Consider crown thinning

In crown thinning, the largest dominant trees, as well as sick and damaged trees, are removed from the forest stand. The next largest and most healthy dominant trees are left in place to grow and become sturdier, In crown thinning, the stand’s rotation period increases by 5–15 years, enabling the trees to sequester more carbon. Crown thinning is not a poor option in terms of the forest owner’s finances either, because it offers more wood trade income immediately, and studies indicate that the highest overall income from the forest’s entire rotation period is obtained if crown thinning is chosen as the last thinning method. Crown thinning is only suitable for well-managed stands with high-quality trees that can be left to grow for 5–15 years.

Fertilise

Fertilisation increases forest growth and helps trees become sturdy more quickly. Faster tree growth and higher wood output per hectare mean that the trees also sequester more carbon than they would without fertilisation.

In growth-enhancing fertilisation, the growth conditions of trees is improved by applying nitrogen fertiliser in the forest, because the lack of nitrogen is the most common factor restricting tree growth. This improves the vitality of trees, as well as their growth. Nitrogen fertilisation improves forest growth for 6–10 years, amounting to a growth increase of 13–25 cubic metres per hectare. Vibrant trees are also more resistant to different types of forest damage.

Corrective fertilisation rectifies nutrient imbalances that impair the normal growth of trees. It enables trees to make full use of forestland’s growth potential and sequester as much carbon as possible. Corrective fertilisation is only carried out on sites where it is needed.

Exercise caution with ditch network maintenance in peatlands

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. 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.

Reforest non-productive land

If your estate has areas that do not grow forest, you could consider their reforestation. You can plant new forest in areas that do not compete with food production, such as pastures or old fields that are no longer cultivated. You can receive state subsidies for reforestation if the area meets the criteria for subsidies, and subsidies remain for distribution in the year in question. Read more here.

Ensure forest biodiversity at all stages of forest management

Dead and decaying wood is needed in addition to carbon sinks. Decaying trees release carbon slowly as they decompose, but they play a very important role in forest biodiversity. Existing dead and decaying trees should therefore be left in place during forestry work, and the amount of decaying wood can be increased by making high biodiversity stumps, for example.

Around a fifth of all species living in Finnish forests depend on decaying wood. This shows how immensely important decaying wood is to the safeguarding of forest biodiversity. In addition to ensuring an adequate amount of decaying wood in the forest, it is important to ensure that it comes in different sizes and at different stages of decay. Decaying wood should be found both lying on the ground and as standing stumps, because different species need different types of it. Read more about forest biodiversity here.