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Silva Fennica 1926-1997
Acta Forestalia Fennica

Articles by Pekka Hänninen

Category : Article

article id 5606, category Article
Pekka E. Kauppi, Pekka Hänninen, Helena M Henttonen, Antti Ihalainen, Eino Lappalainen, Maximilian Posch, Michael Starr, Pekka Tamminen. (1997). Carbon reservoirs in peatlands and forests in the boreal regions of Finland. Silva Fennica vol. 31 no. 1 article id 5606.
Keywords: climate change; boreal forests; peatlands; global warming; carbon reservoirs; carbon pools; global carbon cycles; biomass carbon; ecological temperature gradient
Abstract | View details | Full text in PDF | Author Info

The carbon reservoir of ecosystems was estimated based on field measurements for forests and peatlands on an area in Finland covering 263,000 km2 and extending about 900 km across the boreal zone from south to north. More than two thirds of the reservoir was in peat, and less than ten per cent in trees. Forest ecosystems growing on mineral soils covering 144,000 km2 contained 10–11 kg C m-2 on an average, including both vegetation (3.4 kg C m-2) and soil (uppermost 75 cm; 7.2 kg C m-2). Mire ecosystems covering 65,000 km2 contained an average of 72 kg C m-2 as peat. For the landscape consisting of peatlands, closed and open forests, and inland water, excluding arable and built-up land, a reservoir of 24.6 kg C m-2 was observed. This includes the peat, forest soil and tree biomass. This is an underestimate of the true total reservoir, because there are additional unknown reservoirs in deep soil, lake sediments, woody debris, and ground vegetation. Geographic distributions of the reservoirs were described, analysed and discussed. The highest reservoir, 35–40 kg C m-2, was observed in sub-regions in central western and north western Finland. Many estimates given for the boreal carbon reservoirs have been higher than those of ours. Either the Finnish environment contains less carbon per unit area than the rest of the boreal zone, or the global boreal reservoir has earlier been overestimated. In order to reduce uncertainties of the global estimates, statistically representative measurements are needed especially on Russian and Canadian peatlands.

  • Kauppi, E-mail: pk@mm.unknown (email)
  • Hänninen, E-mail: ph@mm.unknown
  • Henttonen, E-mail: hh@mm.unknown
  • Ihalainen, E-mail: ai@mm.unknown
  • Lappalainen, E-mail: el@mm.unknown
  • Posch, E-mail: mp@mm.unknown
  • Starr, E-mail: ms@mm.unknown
  • Tamminen, E-mail: pt@mm.unknown

Category : Research article

article id 338, category Research article
Andrea Vajda, Ari Venäläinen, Pekka Hänninen, Raimo Sutinen. (2006). Effect of vegetation on snow cover at the northern timberline: a case study in Finnish Lapland. Silva Fennica vol. 40 no. 2 article id 338.
Keywords: climate; snow; forest-tundra; Lapland; radar; tree-line; wind modelling
Abstract | View details | Full text in PDF | Author Info
The presence of permanent snow cover for 200–220 days of the year has a determining role in the energy, hydrological and ecological processes at the climate-driven spruce (Picea abies) timberline in Lapland. Disturbances, such as forest fires or forest harvesting change the vegetation pattern and influence the spatial variation of snow cover. This variability in altered snow conditions (in subarctic Fennoscandia) is still poorly understood. We studied the influence of vegetation on the small-scale spatial variation of snow cover and wind climate in the Tuntsa area that was disturbed by a widespread forest fire in 1960. Radar was applied to measure snow thickness over two vegetation types, the spruce-dominant fire refuge and post-fire treeless tundra. Wind modelling was used to estimate the spatial variation of wind speed and direction. Due to the altered surface roughness and the increased wind velocity, snow drifting was more vigorous on the open tundra, resulting in a 30-cm thinner snow cover and almost half the water equivalent compared to the forest values. The changes in local climate after the fire, particularly in snow cover, may have played an important role in the poor recovery of vegetation: a substantial area is still unforested 40 years after the fire.
  • Vajda, Finnish Meteorogical Institute, Climate and Global Change, P.O. Box 503, FI-00101 Helsinki, Finland E-mail: (email)
  • Venäläinen, Finnish Meteorogical Institute, Climate and Global Change, P.O. Box 503, FI-00101 Helsinki, Finland E-mail:
  • Hänninen, Geological Survey of Finland, P.O. Box 96, FI-02151 Espoo, Finland E-mail:
  • Sutinen, Geological Survey of Finland, P.O. Box 77, FI-96101 Rovaniemi, Finland E-mail:

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