%0 Research article
%T Forest damage caused by the Canadian beaver (Castor canadensis) in South Savo, Finland
%A Härkönen, Sauli
%D 1999
%J Silva Fennica
%V 33
%N 4
%R doi:10.14214/sf.648
%U https://silvafennica.fi/article/648
%X The increasing Canadian beaver (Castor canadensis) population has caused  forest damage in Finland. However, the occurrence, extent and  importance of the damage have not been comprehensively studied. The  field inspection was carried out in all of the beaver damage areas (n =  50) in the Anttola, Juva and Pieksämäki game management units in summer  1998. The characteristics of the damage areas, types of damage and the  severity of the damage were examined. The size of the damage areas  averaged 2.2 ha. The damage areas occurred on peatland forest more (p  < 0.05) than expected. The dominant tree species were commercially  valuable trees such as Scots pine (Pinus sylvestris) (33%), Norway  spruce (Picea abies) (18%) and birches (Betula spp.) (47%). Birch  occurred as dominant tree species more (p < 0.05) than expected. The  proportion of older forest development classes was considerable. The  most important type of damage was flooding (50%) caused by the damming  activity of beavers. The trees were dead or dying in 18% of the damage  areas. It was estimated that the ecosystem engineering performed by  beavers was of no importance in 28% of the damage areas. Prevention of  beaver damage has been carried out in 80% of the damage areas. In the  study area, beaver numbers have steadily increased, although the number  of beavers taken by hunting and the allowed hunting harvest have sharply  increased. It is suggested that the methods used to prevent beaver  damage should be improved and a compensation system should be provided  by the state for the most damaged areas. Beavers can cause damage to  commercial forestry, and this should be taken into account more  effectively in the management plans made by the game management  districts.