Changes in root biomass after water‐level drawdown on pine mires in southern Finland

Abstract

Changes in living and dead root biomass were monitored in the succession created by drainage for forestry on six sites from undrained to 55‐yr‐old drained tall‐sedge pine mires in southern Finland. This was done to evaluate the role of root biomass in carbon cycling in drained peatland ecosystems. The total living Scots pine (Pinus sylvestris L.) root and stump biomass varied from 190 g m2 on an undrained site to 3060 g m2 on the oldest drained site. The pine fine root biomass reached the maximum level within 22 yrs of drainage with a pine stand volume of 81 m3 ha‐1. The pine coarse root and stump biomass increased with the age of the stand, comprising 90% of the total living root biomass on the 55‐yr‐old drained site. The drainage also increased the root biomass of field layer species; however, the roots of sedges were replaced by those of shrubs and trees. The dead fine root biomass was smallest on the two oldest drained sites, which could have resulted from a higher decomposition rate after improved ae...