FO4 Artificial regeneration

>> Background information

Development

Most of the clear felled areas have been regenerated by planting artificially grown seedlings of indigenous tree species. At the moment, there are some 4.4 million hectares of planted forests. Another widespread regeneration practice has been the sowing of seeds, which accounts for approximately one quarter of all artificial regeneration.

In the 1990s the annual planting area decreased by 20% whereas that of seeding increased by 50%. In the 2000s development has been at the opposite direction, but at a slower pace. In the first years of 2010s both seeding and planting areas have started to decrease.

During the 1970s and 80s Scots Pine was clearly preferred in artificial regeneration. This can be seen in the increasing dominance of the species in the tree species composition of Finland's forests (FO9). Since 1990 the number of Scots Pine seedlings delivered for planting has decreased markedly and that of Norway Spruce increased almost equally much. The number of Silver and Downy Birch seedling used in artificial regeneration has also decreased markedly since 1990.

In 2012 the group "other species" contributed to 0.4% of all the seedlings delivered for planting. The species most commonly used were a hybrid Aspen (a crossbreed between the indigenous Common Aspen and North American Quaking Aspen), Curly Birch and Siberian Larch.

Impact on biodiversity

Normally the seeds or seedlings of only one species are sown or planted into the regeneration area. This decreases the diversity of tree species in a forest although natural regeneration of other species always guarantees some heterogeneity in regenerated areas. Especially the volume of deciduous trees is markedly lower in artificially regenerated young forest than in those created by natural regeneration.

Artificially regenerated forests are structurally monotonous roundwood production forests in which the species characteristic to uneven-aged and mixed stands have declined.