Special fellings are applied if the site has, for example, such biodiversity, recreational or landscape values that require preserving its forest cover. Special felling regimes include mature thinning, retention felling, uneven-aged methods and gap felling.
Mature thinning means the thinning of mature (regeneration-ready) forest. Mature thinning may be used to maintain forest cover while promoting the generation of a new seedling stand. After the seedlings are established, the seedling stand can be grown for some time under the seed or shelterwood trees, thereby avoiding an open regeneration phase.
Retention felling is a regeneration felling that leaves clearly more retention trees than usual. It can be applied to landscape sites or sites aimed at increasing the amount of deadwood in the long term.
Uneven-aged management methods
Uneven-aged management methods create and maintain an uneven-aged forest character and forest cover. In uneven-aged felling, the forest is managed by treating groups of trees, while selective felling is mainly the removal of single trees. In both methods, trees are removed on a small scale and the forest is both regenerated and grown simultaneously. In other words, there are trees of many ages and sizes growing continuously on the site.
In gap felling, the site is regenerated in stages and preserving the landscape character, making small gaps that vary in size and shape. Generally, gap felling is applied to 20–25% of the total area of the site. In southern Finland the gaps are up to 0.5 hectares in size, while further north the maximum size of a gap is one hectare.