Fine root productivity and turnover in two evergreen central Himalayan forests

Abstract

Fine root production and mortality in central Himalayan evergreen forests consisting of Quercus leucotrichophora (banj oak) and Pinus roxburghii (chit pine) were measured. Fine root production and mortality decreased with increasing soil depth. Annual fine root production was higher in the broadleafed forest than in the coniferous forest, across months and seasons (1.3 and 1.5-times more living and dead root biomass, respectively in banj oak than in chir pine). Live fine root production was 2508 kg ha-1 year-1 in chir pine forest and 3631 kg ha-1 year-1 in banj oak forest. Dead fine roots accumulated at a rate of 1197 and 1525 kg ha-1 year-1 in chir pine and in banj oak forest, respectively. In both forests, the greatest fine root production was recorded in the rainy season followed by summer and winter seasons. Both soil and root nitrogen concentration decreased with increasing soil depth. Nitrogen uptake was higher in banj oak forest (12.1 kg ha-1 year-1) than chir pine forest (7.2 kg ha-1 year-1).