wise use of mires and peatlands - Peatland Ecology Research Group

VALUES AND FUCTIONS OF MIRES AND PEATLANDS63– frequent ground frosts,– temperatures in the growing period whichare on average too low.Peatlands have a specific microclimate 110 .Compared with the surrounding area, apeatland has a greater variation intemperature, a higher frequency of frostoccurrence and higher air humidity. Thereason is that peatlands are usually found interrain depressions (valleys, hollows) intowhich cooler air flows. As a consequence,the soils of both pristine and reclaimedpeatlands are significantly cooler in summerthan mineral soils, and the air temperature isalso lower. The microclimate of peatlandsthus creates significantly more severe climaticconditions for agricultural plants than themicroclimate of the surrounding mineral soils.This results in agriculture on peatlands in thenorthern hemisphere taking place in moresouthern latitudes than similar agriculturalactivity on mineral soil. Cooler climaticconditions are more favourable for trees andshrubs and for meadows and pastures.Landscape position: Depending on thelocation of the wetland in the surroundingterrain, the excess of water may be removedby gravity drainage or pumping. The drainagenetwork is more intensive in deposits with agreater depth of peat and where there is springwater. Additional difficulties occur in floodedriver valleys and in depressions. The moredifficult and expensive the maintenance ofthe required ground water depth and of themoisture in the root layer of cultivated plants,the smaller the possibility of a permanentutilisation of the peatland.Type of peat deposit: In the majority ofEuropean countries the utilisation ofpeatlands as arable land was thought to beadvisable only on shallow (