ROOT DYNAMICS AT DRAINED PEATLAND SITES OF DIFFERENT FERTILITY IN SOUTHERN FINLAND

Root (diameter less than or equal to 10 mm) biomass and production was studied in three Scots pine stands growing on drained peatland sites of different fertility in southern Finland with the sequential coring method during three growing seasons. Both the living and dead root bio masses increased with a decrease in the fertility of the sites. Mean t hree-year annual Scots pine root production on the sites varied betwee n 65-112 g m(-2) calculated by balancing transfers in the statisticall y significant changes in monthly living and dead root biomasses, and b etween 221-309 g m(-2), in the case where all changes were accounted. The field layer root production for the sites was 36-156 g m(-2) and 1 80-279 g m(-2), respectively. Scots pine root production was somewhat greater on the nutrient poor site than on the other sites, whereas the field layer root production was greater on the richer sites. However, the differences in root production between the sites were not statist ically significant due to the high variation. Scots pine root turnover did not vary between sites, whereas, that of the field layer was grea ter on the richer sites and also greater than that of Scots pine roots . The results also indicate that root production is positively affecte d by soil temperature and soil aeration on drained peatlands.