Northern forests do not benefit from lengthening growing season

Forests in northern areas are stunted, verging on the edge of survival. It has been anticipated that climate change improves their growth conditions. A study published last week in Forest Ecology and Management journal shows that due to their genetic characteristics trees are unable to properly benefit from the lengthening growing season. Furthermore, the researchers were surprised to find that the mortality of established trees considerably promotes the adaptation of forests to the changing environment.

In cooperation with colleagues at the Universities of Oulu and Potsdam, Anna Kuparinen, Docent at the University of Helsinki’s Faculty of Biological and Environmental Sciences, simulated forest growth from southern to northern Finland. A meteorological dispersal model was applied to describe the spread of pollen and seeds in the atmosphere. Above all, the results illustrate the slowness of the adaptation process.

Generally, trees stop growing before the frosts and this cessation of growth has been programmed in their genotype. Therefore, trees are unable to effectively follow the increasing environmental growing season. Instead, they cease growth as dictated by their genotype. It is estimated that after hundred years from now northern forests will substantially lag behind the speed of growth that would be enabled by their environment.

Evolution is promoted by the mortality of established trees

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