Abstract. In Finland, Olkiluoto Island on the western coast has been selected as a repository site for spent nuclear fuel. Due to the shallow sea areas around the island, the postglacial land uplift is going to change the landscape within the next millennia. For instance, new lakes and mires will develop on the present offshore areas. Concerning radionuclide transport models, the properties of the future ecosystems surrounding Olkiluoto Island can be forecast based on the properties of present lakes and mires. Due to the lack of site-specific data, lakes and mires of various successional stages were selected within a larger geographical area as analogues of the future ones. Here we present an example of a systematic process for selection of appropriate analogue sites.
Biomass production and nutrient use of birch thickets with a mixture of willow on a cut away peatland in southern Finland over a period of 37 years was studied. Dense, naturally regenerated 16yearold birch stands were cut down, fertilized with either wood ash (P 108 and K 339 kg ha -1 ) or PK fertilizer (P 50 and K 95 kg ha -1 ) or left unfertilized. The biomass production of the coppiced stands and one uncut stand was monitored for a period of 21 years. Soil nutrient and foliar nutrient concentrations were analyzed several times during the study period. Ash fertilization supplied more nutrients than PK fertilization and increased the soil nutrient amounts more. The foliar phosphorus concentration of birch on control plots indicated a severe phosphorus deficiency which was removed by PK and ash fertilization. Fertilization did not increase nutrient concentrations of the stem (wood + bark) nor the amount of nutrients bound in the biomass. Two energy wood rotations (16+21 years) produced 124-158 Mg ha -1 of leafless, aboveground biomass altogether corresponding to 61-78 Mg ha -1 of carbon. The highest biomass yield was achieved with a rotation of 37 years in the uncut stand (211 Mg ha -1 ). Corresponding values for mean annual increment (MAI) were 3.4-4.3 Mg ha -1 and 5.7 Mg ha -1 . This study shows that the length of the rotation for birch in energy wood production should be longer than 21 years. PK and ash fertilization increased the biomass of coppiced 21yearold birch by 23 Mg ha -1 and 33 Mg ha -1 , respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.