Antti Lännenpää, Tuomas Aakala, Heikki Kauhanen, Timo Kuuluvainen. (2008). Tree mortality agents in pristine Norway spruce forests in northern Fennoscandia. Silva Fennica vol. 42 no. 2 article id 468. https://doi.org/10.14214/sf.468

Keywords: Picea abies; northern Fennoscandia; Coniophora; mortality agent; pristine forest

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We examined tree mortality agents in pristine old Norway spruce (Picea abies (L.) Karst.) forests in northern Finland and northwestern Russia. The data was collected on nine 40 m 400 m transects. The primary mortality agents of recently dead trees were recorded and their frequencies were calculated. The pattern of tree growth prior to death was studied based on increment core samples and compared with the growth of healthy dominant trees. Of all recently dead trees, 72% could be associated with a primary mortality agent. In both study areas the most common primary mortality agent was a Coniophora (Mérat) DC. -genus fungi, which was found on average in 33% of trees sampled. The fungi Phellinus chrysoloma (Fr.) Don and Onnia leporina (Fr.) H. Jahn as mortality agents were more common in the Finnish area compared to the Russian area. Analysis on the growth patterns indicated weak differences between different pathogens’ influence on prior-to-death growth of trees, so that fungi rotting the whole tree decreased tree growth more rapidly than fungi rotting only the heart wood. The results demonstrated that in old Norway spruce forests of northern Fennoscandia the most common primary tree mortality agents were wood rotting fungi, which weaken the mechanical stability of tree stems until they fall due to snow or wind, which should be considered only as secondary mortality agents. It is evident that tree death in pristine forest typically results from a long-lasting process involving both biotic and abiotic factors.

Lännenpää, Department of Forest Ecology, University of Helsinki, Finland E-mail: al@nn.fi
Aakala, Department of Forest Ecology, University of Helsinki, Finland E-mail: tuomas.aakala@helsinki.fi
Kauhanen, Kolari Research Unit, Finnish Forest Research Institute, Finland E-mail: hk@nn.fi
Kuuluvainen, Department of Forest Ecology, University of Helsinki, Finland E-mail: tk@nn.fi

Category : Research note

article id 569, category Research note

Heikki Kauhanen. (2002). Occurrence of fires in the eastern Saariselkä area, north-west Russia. Silva Fennica vol. 36 no. 1 article id 569. https://doi.org/10.14214/sf.569

Keywords: fire; anthropogenic fire; burn; Russia; satellite image; vegetation mosaic

Abstract | View details | Full text in PDF | Author Info

The occurrence of fires was studied in the eastern Saariselkä area, North-West Russia, by using satellite images and topographical maps. In total, more than 330 burned areas were pinpointed in the study area of 4770 km2. Old burns were concentrated in the eastern part of the study area, but young burns were more common in the west. Sites affected by fires in the more recent past were much smaller than those burnt over earlier. The abundance of burns along rivers and the border surveillance road provided evidence of human impact. The most significant changes in the landscape were found in the eastern part of the study area, where spruce forests had been replaced by birch woodlands.

Kauhanen, Finnish Forest Research Institute, Kolari Research Station, Muoniontie 21 A, FIN-95900 Kolari, Finland E-mail: heikki.kauhanen@metla.fi

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