Morphological adaptations of fine roots in Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth.) and black alder (Alnus glutinosa (L.) Gaertn.) stands in recultivated areas of oil shale mining and semicoke hills

The present research was carried out in Scots pine, black alder and silver birch stands of different age in Estonia in 2004 to analyse fine root morphological adaptations in recultivated areas of opencast oil shale mining and semicoke hills. Morphological adaptation of short roots to corresponding soil conditions was specific for tree species. Functional root characteristics SRA (m(2) kg(-1)), SRL (m kg(-1)) and RTD (kg m(-3)) differed significantly among coniferous and deciduous tree species, with lowest SRA and SRL values and highest RTD values being found in Scots pine. The means of short root SRA varied from 43 to 68 m kg(-1) for pine; from 79 to 155 m(2) kg(-1) for alder and from 157 to 194 m(2) kg(-1) for bitch. The impact of tree age on short-root parameters was significant for deciduous tree species. Root parameters on semicoke areas depend on the microbial community, as proved by the bioaugmentation experiment.