In Switzerland’s forests, artificial regeneration is declining in favor of natural regeneration.

Shares of regeneration types in Switzerland’s overall young woodland area in the 1983/85, 1993/95, and 2004/06 surveying periods, indicated in percent with a 95% confidence interval.

Regeneration type	1983/85	1993/95	2004/06
Artificial regeneration	24 ± 3	16 ± 4	5 ± 2
Mixed regeneration	26 ± 3	25 ± 4	17 ± 4
Natural regeneration	50 ± 4	59 ± 5	78 ± 4

Interpretation Example
In the surveying periods of 1983/85, 1993/95, and 2004/06, the share of artificial regeneration in Switzerland’s overall young woodland area was 21-27%, 12-20%, and 3-7% respectively.

Comments
• In the past twenty years, natural regeneration has continually been increasing its share in Switzerland’s young woodland area: While it only reached a roughly 50% share in the 1983/85 surveying period, that share increased to 60% in 1993/95 and to just under 80% in 2004/06.

• Between 1983/85 and 2004/06, the area of artificially regenerated young woodland shrank by roughly 140 square kilometers. During that time period, the area of naturally regenerated woodland increased by 186 square kilometers.

• The share of young woodland in the overall forest stand slightly declined (from 5.9% to 5.3%) between 1983/85 and 2004/06. In the 2004/06 surveying period, roughly 684 square kilometers of Switzerland’s forests consisted of young woodland.

Source
Swiss National Forest Inventory NFI, special analyses of the surveys taken in 1983/85, 1993/95 and 2004/06. 26122008UU. Swiss Federal Institute for Forest, Snow and Landscape Research WSL. CH-8903 Birmensdorf.

Status
February 2009. The next update will be made after the fourth Swiss National Forest Inventory (NFI4) has been finalized. NFI4 surveys are scheduled for 2009/17.

In the past twenty years, the share of naturally regenerated young woodland has increased, while plantations continue to lose in importance. Nowadays, 80% of Switzerland’s forests are regenerated the natural way. When young trees are planted at all, they mostly serve to strengthen avalanche protection forests, selectively promote biodiversity, or produce timber.

In the last century, economic reasons led to uniform spruce forest plantations invading the traditional beech forest range. In the meantime, however, the share of coniferous species in young woodland has declined again, which by the 1990s resulted in young stands holding a larger share of deciduous species than old stands. It appears that a more natural type of silviculture allowed an increasing number of site-appropriate habitats to develop.

Windthrow, fires, or forest management create gaps in a forest. If such clearings are left to their own devices, they will soon be colonized by pioneer species that benefit from the light available in open spaces. After a certain period of time, pioneer plants are displaced by other species which in turn will be replaced by the slow growing “final vegetation”, with each phase of this process being characterized by different plant and animal species. From the beginning, stands that have grown this way will be rich in structures and—typically—species, remaining diverse given appropriate care. Moreover, such natural regeneration helps to maintain local tree species which are genetically particularly well suited to site-specific conditions.

Responsible for E9
Lukas Kohli, kohli@hintermannweber.ch, +41 (0)31 312 82 72
Fachkontakt LFI: Urs-Beat Brändli, urs-beat.braendli@wsl.ch, +41 (0)44 739 23 43

Other possible information sources
> National Forest Inventory