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Published: 2021-06-18

Forestry has little impact on the genetic diversity of the spruce

NEWS The genetic variation in spruce does not differ significantly between cultivated and old forest from the coast to mountain areas in Västerbotten. But with new forestry methods in the future, risks may arise. Helena Eklöf defended her thesis on Friday 26 March at Umeå University.

Text: Ingrid Söderbergh

Genetic diversity, the variation that exists in the genome of organisms, is necessary in all species in order to preserve the ability to adapt to changing climates and new environments. In Sweden, we conduct large-scale forestry with felling and replanting over large areas, but lack in-depth knowledge of how this has affected the spruce's genetic diversity.

In her dissertation, Helena Eklöf has focused on developing a basic value for the genetic diversity that we find today in old spruce forests that are preserved in nature reserves. She has thereafter compared the basic value with the genetic diversity found in young, replanted spruce forests in Västerbotten.

Common parameters used to measure genetic diversity are, for example, gene variants that are only included in a population, how large the proportion of unusual gene variants is, how closely related individuals in the same population are and what the mean value of heterozygosity is in each population.

Several parameters showed no difference in mean values ​​between old spruce stands and young replanted spruce stands. But despite the fact that average values ​​did not differ, the young spruce stands showed a greater spread, where both the lowest and highest values ​​were found.

“The greater spread we see among the replanted stocks indicates that there are factors that affect how genetic diversity is distributed between the forest stands,” says Helena Eklöf. “It can be anything from seed collection, to planting or thinning that causes the pattern.”

To ensure what this is due to, more in-depth research is required on the variation that exists within a stand and how this is affected by modern forestry methods.

“The fact that we do not see a major difference in genetic variation in spruce today does not mean that there is a risk that forestry can cause long-term effects. We must carefully monitor the development and be aware of the risks that come with, for example, a possible introduction of clone forestry, where identical individuals of the same tree are used instead of sowing seeds or pushing plants up from seeds, says Helena Eklöf.

Helena Eklöf was born and raised in Umeå. She has a bachelor's and master's degree in biology and ecology from Umeå University.

Read the whole dissertation: Genetic diversity and differentiation in natural and managed stands of Norway spruce (Picea abies)