Articles containing the keyword 'tulva-alueet'
Category : Article
The aim of the study was to determine which kinds of insects had infected the Norway spruce (Picea abies (L.) H. Karst.) in different stands killed by flooding caused by beavers (Castor canadensis Kuhl), and if there was any danger that they would subsequently cause damage in the surrounding forests. The effect of tree diameter and certain stand characteristics on the fauna of dead trees are discussed. The occurrence of different insect combinations and qualifications for their coexistence were studied.
Pityogenes chalcographus L., Trypodendron lineatum O., Hylurgops palliatus Gyll. and Dryocetes autographus Ratz. occurred most abundantly. 20 phloem or wood boring species were observed in 5 regular succession types. Secondary species occurred in a virgin stand while Ips typographus L. was found at the edge of a felling area. Owing to the flooding, species preferring moist conditions were abundant. In this case damages had not spread to the surrounding forests which, however, might be possible under certain conditions.
The PDF includes a summary in English.
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Saarenmaa,
E-mail:
hs@mm.unknown
Distribution of European white elm (Ulmus laevis Pallas) is on its northernmost border in Pyhäjärvi and Kokemäenjoki area. This survey describes distribution of European white elm in the flooded shores of the central lake of Pyhäjärvi and Kokemäenjoki river water system.
Both Ulmus laevis and U. montana (now U. Glabra Hudson) can be found in the area, but most of the elms qrowing in thea area are U. laevis. U. laevis occurs around the lake in two separate areas, almost entirely in flooded shores of the lake. Regeneration of elm from seeds was limited on a narrow belt on the higher part of the flooded shore. Consequently, U. laevis can be found as zones around the lake, created by the changes in water level of the lake. The trees are judged to be native for the area.
The article includes an abstract in German.
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Saarnijoki,
E-mail:
ss@mm.unknown
