Soil preparation improves seedling growth and increases carbon sequestration

High-quality soil preparation is a requirement for successful forest regeneration and one of the main tasks in forestry. Successful soil preparation facilitates cultivation, helps seedlings start growing, prevents damage caused by the pine weevil, reduces future needs for young stand management and makes wood production more profitable long into the future.

Soil preparation also improves the carbon sequestration of forests: research indicates that a forest planted in prepared soil sequesters more carbon during its first few decades than one established in unprepared soil. Prepared soil provides seedlings with better growth conditions, helping them grow and stay alive better than unprepared soil. A densely growing forest also sequesters carbon more efficiently.

Method of soil preparation chosen to suit the growth site

In soil preparation, the surface layer of forest land is removed in places to ensure the seedlings to be planted or the seeds to be sown get the best possible growth conditions in terms of humidity and heat conditions. In mineral soils, soil preparation forms protuberances with a surface layer of mineral soil such as sand, fine sand or silt. Nutrient-rich humus soil remains inside the mounds. In peatlands, the surface of the mound consists of decomposed peat.

Your personal forest specialist can choose the most suitable soil preparation method for your forest, based on the growth site’s nutrient content, soil type and moisture content. We favour inverting as a soil preparation method, because it provides seedlings with good growth conditions, is environmentally friendly and reduces the future costs of young stand management. The soil preparation service is only available in Finland.

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Plant new trees immediately after soil preparation

Soil preparation is carried out at the latest in the summer season following regeneration felling. We perform soil preparation with an excavator (mounding and scalping) or a forestry tractor (harrowing and ploughing). We avoid breaking the soil unnecessarily in all methods. After soil preparation, the area contains a number of prepared spots equal to the planned cultivation density, excluding stony ground, ditches and other areas unsuitable for soil preparation.

Seedlings should be planted as soon as possible in a freshly prepared spot. The best time for sowing is in the spring as soon as the snow melts. Areas prepared in the autumn can also be cultivated during the following growing season. Seedlings are planted in the centre of the mound, usually at the highest spot. Plant the seedling deep enough for the root ball to be covered by approximately 5 cm of soil. Detailed instructions for planting seedlings can be found here.

Biodiversity is taken into account in soil preparation

Soil preparation rarely has any notable adverse environmental impacts in mineral soils. Although soil preparation releases nutrients, the soil and vegetation retain them efficiently, ensuring that any washout is minor.

Any negative impacts on the landscape can be reduced by adopting lighter soil preparation methods. When preparing the regeneration plan, attention can also be paid to fallen decaying trees, retention trees and protective thickets that are left in regeneration areas to safeguard biodiversity, and they can be excluded from soil preparation.