Current issue: 53(4)

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Silva Fennica 1926-1997
Acta Forestalia Fennica

Articles by Pekka Helle

Category: Research article

article id 151, category Research article
Janne Miettinen, Pekka Helle, Ari Nikula, Pekka Niemelä. (2010). Capercaillie (Tetrao urogallus) habitat characteristics in north-boreal Finland. Silva Fennica vol. 44 no. 2 article id 151.
This study aimed to identify tools for taking capercaillie habitats into consideration in forest management. This would provide new alternatives for ecologically more sustainable forest management. Capercaillie summer and winter locations, from wildlife monitoring counts (1998–2004) in northern Finland, and reference, non-capercaillie locations were combined with forest planning data, and the area proportions of different landscape classes in an 800-m radius circle surrounding capercaillie and reference locations were compared. Thinning stands (in summer and winter) and spruce mires (in summer) were more abundant in capercaillie habitats than in reference landscapes, whereas e.g. seedling stands, mature stands and waste land areas were less abundant. The relative habitat use was highest in mean tree diameter (DBH) classes from 10.5 to 14.5 cm in summer habitats of adult capercaillie in heath forests, whereas in peatland forests, in brood habitats and in winter habitats it peaked in diameter classes 14.5 to 18.5 cm. The tree layer density was positively associated with the relative habitat use. A trend of lower habitat use was detected in the largest diameters (17–40 cm) in comparison to middle-sized diameters (10–16 cm) in heath forests, but not in peatland forests. Relatively young managed forests (age 30–40 years or more) can form suitable capercaillie habitats in north-boreal forests. However, this suitability is not necessarily permanent. Understorey management, longer rotations and multicohort forest management are suitable tools for capercaillie habitat management, because they can increase the available cover close to the ground, canopy cover, overall forest cover at the landscape scale and bilberry cover.
  • Miettinen, Finnish Game and Fisheries Research Institute, Finland ORCID ID:E-mail: (email)
  • Helle, Finnish Game and Fisheries Research Institute, Finland ORCID ID:E-mail:
  • Nikula, Finnish Forest Research Institute, Finland ORCID ID:E-mail:
  • Niemelä, University of Turku, Dept of Biology ORCID ID:E-mail:
article id 182, category Research article
Janne Miettinen, Pekka Helle, Ari Nikula, Pekka Niemelä. (2009). Changes in landscape-scale habitat selection of capercaillie (Tetrao urogallus) in managed north-boreal forest. Silva Fennica vol. 43 no. 4 article id 182.
We studied changes in habitat selection of capercaillie in northern Finnish boreal forests at two spatial scales during two time periods, 1989–1992 and 2000–2003. We studied capercaillie densities and their changes between the study periods in relation to the landscape class proportions within 3-km buffer zones around the wildlife triangle center points. Furthermore, we compared the landscape class proportions in 800-meter buffer zones around capercaillie wildlife triangle count observations and around the counted wildlife triangle transects using t-tests and compositional analysis. At the local population scale (3 km) the change in adult density between the study periods was associated positively with the proportion of young thinning stands in 2003 and reversely with the mature stand (1992 and 2003) and clear-cut (1992) proportions. Capercaillie juvenile and pooled densities during 2000–2003 were positively associated with the advanced thinning stand proportion in 2003. At the capercaillie home range scale (800 m) habitats were rich in mature stands during 1989–1992 in relation to available habitats, but not during 2000–2003 when young thinning stands were more abundant in relation to available habitats. Relatively young managed forests can be suitable for capercaillie, but mature managed forests as capercaillie habitats may have deteriorated between the study periods. Spatial planning may help to form suitable areas that are large enough for the species, but the highest potential may lay in the forest stand scale, where increased cover on the ground could promote the habitat quality.
  • Miettinen, Kankurinhaka 14, FI-90450 Kempele, Finland ORCID ID:E-mail: (email)
  • Helle, Finnish Game and Fisheries Research Institute, Tutkijantie 2 E, FI-90570 Oulu, Finland ORCID ID:E-mail:
  • Nikula, Finnish Forest Research Institute, Rovaniemi Research Unit, Eteläranta 55, FI-99600 Rovaniemi, Finland ORCID ID:E-mail:
  • Niemelä, University of Turku, Department of Biology, FI-20014 University of Turku, Finland ORCID ID:E-mail:

Category: Article

article id 5245, category Article
Pekka Helle, Jyrki Muona. (1985). Invertebrate numbers in edges between clearfellings and mature forests in Northern Finland. Silva Fennica vol. 19 no. 3 article id 5245.

The abundance of main invertebrate groups was studied in clear-fellings, forests and in edges between them in Northern Finland in June-August 1983. Five trapping transects were used. Each transect had 48 pitfall traps and 16 window traps on the ground and 4-6 window traps in bushes or trees.

Invertebrate groups Homoptera, Diptera, Formicidae, Coleoptera and Gastropoda were more abundant in forest than in clear-cuts according to the pitfall data. In window traps the catches of all the main groups were larger in the forest side. Six out of the eight most important groups preferred the edge in pitfall data. Formicidae, other Hymenoptera, Arachnida and Gastropoda were more numerous in the edges than in the interior habitats in both sides of the edge. In window trap material no consistent edge preference was found in clear-fellings, but in the forest side it was evident. Coleoptera and Arachnida preferred the edge on both sides of it.

The variations in the catches of the invertebrate groups were studied by regression analyses. Independent variables used were the distance to the edge, the coverage of mosses, litter, mineral soil, grasses and sedges, herbs and the density of saplings. The percentage of variance explained in multiple regression analyses were highest for the group of other Hymenoptera and Arachnida and lowest for Coleoptera and Homoptera. As regards the explanation power of the independent variables the distance to the edge and the density of saplings clearly exceeded the others.

The results support the assumption that the breeding bird densities at forest edges, which is often high, may depend on high prey density there.

The PDF includes a summary in Finnish.

  • Helle, ORCID ID:E-mail:
  • Muona, ORCID ID:E-mail:

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