These peatlands have a permanently frozen ground underneath, the permafrost, and the carbon was able to build up in these soils over long periods of time because even though plants are able to photosynthesize during the short, warm summer months, the environment quickly turns cold and dark, and then microbes are not able to efficiently break down the residue.
Ova tresetna tla imaju sloj trajno smrznutog tla ispod površine, tzv. permafrost, i ugljik se u ta tla vezao tijekom dugog niza godina, zato jer iako su biljke sposobne  za fotosintezu u kratkim, toplim ljetnim mjesecima, okoliš brzo postaje mračan i hladan, a onda mikrobi ne mogu dovoljno  učinkovito razgraditi naslage.