Reijo Solantie

Karttoja suo-ojitusten vaikutuksesta Suomen ilmastoon

Solantie R. Karttoja suo-ojitusten vaikutuksesta Suomen ilmastoon.

English title: Charts of the climatic impact of the drainage of mires in Finland

Tiivistelmä

Widespread drainage measures, which were carried out mainly in the period 1950- 1990 on Finnish mires, have had significant climatic consequences, part of them being temporary, part permanent. The aim of this study was to prepare charts of these climatic effects by combining three sources of knowledge: (I) the climatic effect of drainage (e, °C), as given by (Solantie 1994, 1998) for a 100% mire area in the climatically most affecting stage, (2) fresh grid-square statistics of the proportion of drained mires compared with the total area, and (3) annual statistics of the proportion of drained mires in various stages having characteristic climatic effects, compiled by the Finnish Forest Research Institute. Three charts show the maximum cooling effect of peatland drainage in Finland during the first 15 years after the drainage in the period 1973-1982, as drained mires in such a stage of drainage were then most common. Two charts show the warming effect after successful afforestation and canopy closure; the canopy acts as a radiation shelter and a mixing generator for the air beneath. In the middle boreal natural zone, that most heavily drained, the mean monthly minimum temperatures in the period 1973-1982 were reduced by 1.5°C and the yearly frost-free period was shortened by 17 days. As a result of successful afforestation, the annual minimum temperature in the middle boreal zone will be raised by 2°C to 3°C by the year 2005.

Avainsanat
Drainage; mire; climate; foresrty

Vastaanotettu 31.10.2017 Julkaistu 1.1.1999

Katselukerrat 1231

Saatavilla http://suo.fi/article/9784 | Lataa PDF

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