Page 32 - Green knowledge 2024

Photo: Kjersti Holt Hanssen
Opening up for more continuous cover forestry
How we harvest forests affects carbon sequestration, biodiversity, water quality and timber
yield.
Clear-cutting has been the dominant logging method
in Norway since World War II. An alternative to
clear-cutting is what’s known as continuous cover
forestry (CCF).
CCF entails a suite of silvicultural systems including
the selection-, shelterwood- and group systems. They
have in common that at each harvest intervention,
only some of the trees are felled, ensuring a continu-
ous cover of trees. There is currently a growing inter-
est in CCF in Norway, which suggests that the pro-
portion of CCF will increase in the coming years.
Local conditions, such as the risk of windthrow,
influence how suitable the forest is for CCF. A chal-
lenge is that a significant proportion of today’s for-
ests are dense even-aged stands which are vulnerable
to windthrow after partial harvesting. Nevertheless,
new studies conducted by NIBIO, NINA and NIVA
show that the potential could be considerably greater
than what is currently utilised. As much as 38 per-
cent of the forest area in mature coniferous forest
may be suitable for CCF.
Different proportions of CCF also affect carbon
uptake. Model simulations showed that the scenario
with the highest proportion of CCF resulted in an
additional uptake of nearly 32 million tonnes of CO2
by 2100. However, the simulations also showed that
to be able to harvest the same timber volume as in a
scenario reflecting current practice, an increased
proportion of CCF would also require logging on a
larger proportion of the forest area.
The study also showed that more CCF could have
positive implications for certain aspects of biodiver-
sity, primarily mycorrhizal fungi and other species
that require shaded conditions. However, harvesting
across a larger total area could negatively impact
other animals, plants and fungi.
Purpose: Collaboration: Enhanced knowledge about continuous cover forestry.
Norwegian Institute for Nature Research (NINA) and Research institute for water and the
environment (NIVA)
Funding: Norwegian Environment Agency
Contact: Head of Department/Head of Research Aksel Granhus, Division of Forest and Forest Resources.
Email: aksel.granhus@nibio.no | Phone:
+
47 977 14 873
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