Kari Puukko. (1981). Okakaarnakuoriaisen, Ips acuminatus Gyll. (Coleoptera, Scolytidae) levinneisyyden nykyinen eteläraja Suomessa. Silva Fennica vol. 15 no. 2 article id 5119. https://doi.org/10.14214/sf.a15060

English title: The southern border of the present distribution of Ips acuminatus Gyll. In Finland.

Original keywords: hakkuut; metsätalous; levinneisyys; kaarnakuoriaiset; esiintymisalue; okakaarnakuoriainen

English keywords: bark beetles; forestry; Finland; distribution; Ips acuminatus; loggings

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

Ips acuminatus Gyll. (Coleoptera, Scolytidae) is a bark beetle that causes deep bluing in thin-barked Scots pine (Pinus sylvestris L.) pulpwood. It has been shown that this decreases pulp yield. The purpose of this study was to map the southern border of the distribution of Ips acuminatus in Finland. It was found that there have been changes in the distribution of this species during the last three decades. Ips acuminatus has now disappeared from southern Finland. On the basis of the sample plots (134 cutting areas) the southern border of this pest lies on the line running through the towns Vaasa–Seinäjoki–Äänekoski–Jyväskylä–Pieksämäki–Savonlinna–Punkaharju. A certain degree of localisation was observed in the occurrence of I. acuminatus in its distribution area, for instance, differences in its occurrence frequency in cutting areas and even in log and cutting residue piles in the sample cutting area.

It is considered that the most important reasons for these changes in distribution are the increase in logging and changes in the location of cutting sites, and resulting competition for breeding material for the increased population of bark beetles. Furthermore, the long-distance transport of unpeeled logs from the north across the present southern borders may, in the future, contribute to local changes in the southern distribution of Ips acuminatus.

The PDF includes a summary in English.

Puukko, E-mail: kp@mm.unknown

Category : Research note

article id 1145, category Research note

Juha Siitonen. (2014). Ips acuminatus kills pines in southern Finland. Silva Fennica vol. 48 no. 4 article id 1145. https://doi.org/10.14214/sf.1145

Keywords: tree mortality; Scots pine; Ips acuminatus; Phaenops cyanea; drought

Highlights: Recently dead pines colonized by Ips acuminatus were frequently found in southern Finland, in a region where the species was thought to be absent; Colonized trees were typically large (average DBH 30 cm), located at open spots in pine-dominated stands, often forming groups of several trees; The damages may be a consequence of dry and hot summers during the 2000s.

Abstract | Full text in HTML | Full text in PDF | Author Info

Recently dead Scots pines (Pinus sylvestris L.) apparently killed by Ips acuminatus (Gyllenhal) were observed in Sipoo, southern Finland, in summer 2013. This record was unexpected and in contradiction with what is currently known about the distribution and aggressiveness of the species in Finland. The aim of this study was to survey a larger area in Uusimaa region, to find out whether I. acuminatus occurs frequently in recently dead pines, and whether inhabited trees share some common tree- or site-level characteristics. Galleries of I. acuminatus were found in most of the studied trees. A total of 96 inhabited trees were found in 21 separate sites. Colonized pines were typically large (average DBH 30 ± 9 cm) trees located in relatively open pine-dominated heathland stands at half-open, sun-exposed spots. The whole upper part of the trunk with thin bark was usually occupied. Galleries of Tomicus piniperda L. or T. minor Hartig occurred only in few cases in the same trees, indicating that the trees had died later in the summer. Galleries of the jewel beetle Phaenops cyanea F. were found in 13 trees. Trees colonized by I. acuminatus often occurred as small groups, with generally 1–12 trees (average 3 trees), but in one exceptional group there were no less than 35 trees. It is possible that the hot and dry summers during the 2000s have increased the susceptibility of pines to insect damage, and have contributed to a population growth of I. acuminatus.

Siitonen, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: juha.siitonen@metla.fi

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