Fine root biomass dynamics and carbon storage along a successional gradient in Changbai Mountains, China

Fine root dynamics and net primary production were studied using the sequential soil coring method in an old-growth Korean pine (Pinus koraiensis Sieb.et Zucc.) mixed broadleaved forest, an 80-year-old stand of secondary birch (Betula platyphylla Suks.) in mixture with poplar (Populus davidiana Dode) and a 20-year-old stand of secondary birch and poplar in Changbai Mountains in Northeast China. The biomass and necromass of the fine roots in the 0- to 0.5-m soil layer were determined every month from May to October in three types of forest during 2002. The total and monthly production dynamics of the fine roots were calculated and analysed according to seasonal biomass changes along the successional gradient, as well as their carbon and nitrogen contents. The total production of the fine roots from the dominant tree species increased along the successional gradient, being 222.8, 569.1 and 672.3 g m(-2) from the young forest through to the old-growth stage, respectively. As important soil carbon and nitrogen sources, the total carbon and nitrogen storages by fine root growth increased along forest succession in the Changbai Mountains.