Tree recovery during the aftermath of an outbreak episode of the Hungarian spruce scale in southern Sweden

Research output: Contribution to journalArticle


In 2010, the first, and so far only, infestation of the Hungarian spruce scale (Physokermes inopinatus) and accompanying sooty mould occurred in Scania, southernmost Sweden. About 1000 ha of Norway spruce (Picea abies) were affected, and the trees suffered from the sucking of the insects as well as from the dense sooty mould that covered the needles. Salvage cuttings were carried out in many of the massively attacked forest stands, both in response to the fear that the trees otherwise would die, e.g. from secondary bark beetle attacks and to prevent spreading of the infestation. The aim of this study was to provide basic, quantitative knowledge on the aftermath response of trees that were heavily infested, but not exposed to salvage cutting. Growth characteristics, in terms of needle weight, shoot length and tree-ring size were measured on infested and uninfested trees to compare and contrast the spruce growth before, during and after the scale outbreak. The infestation resulted in dwarf annual shoots, stunted needles and thin tree rings. The needle weight returned to normal the following year, whereas shoot length and tree rings required one growing season before full recovery.


Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Forest Science


  • needle weight, Physokermes inopinatus, Picea abies, shoot length, tree ring
Original languageEnglish
Pages (from-to)313-319
JournalScandinavian Journal of Forest Research
Issue number4
Early online date2018 Jan 18
Publication statusPublished - 2018 May 19
Publication categoryResearch

Related projects

Inis Winde & Olle Anderbrant


Project: Research

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