Raimo Heikkilä

Karujen rämeiden ja nevojen ojituksista, erityisesti Etelä-Pohjanmaalla

Heikkilä R. Karujen rämeiden ja nevojen ojituksista, erityisesti Etelä-Pohjanmaalla.

Tiivistelmä

Forestry drainage of sparsely tree covered and treeless poor mires was studied on the basis of mire type and drainage knowledge of peat investigation reports of the Geological Survey of Finland. The material was checked by aerial photos and field investigations, and from the drainage plarts of the organisation responsible for the drainage. Drainage of the studied mire types is known to be unprofitable. The propor-tion of unprofitably drained mire types of each studied mire was calculated. Of the total mire area studied, 79891 ha, some 13800 ha was unprofitably ameliorated, i.e. 35 % of total drained area on the studied mires. In Southern Ostrobothnia 2190 ha was studied in detail There 650 ha had been unprofitably drained, i.e. 30 % of drained area. The reason for the unprofitability of the amelioration was usually false deter-mination of mire types. The amount of trees on the mires has also often been overestimated. The results cannot be generalized to all mires and ameliorations in Finland, because the studied mires were rather large, minimum area being 20 ha. On such mires the proportion of poor sparsely tree covered and treeless mire types is greater than on finhish mires in general. Smaller mires are often densely tree covered pine or spruce swamps, the amelioration of which is usually profitable. The confidence of the results is best in Southern Ostrobothnia, where also some small mires were studied. Further investigations are anyway necessary.

Vastaanotettu 31.10.2017 Julkaistu 1.1.1984

Katselukerrat 1110

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