Effect of forest drainage on the carbon balance of a mire: A case study

Abstract

Natural mires generally act as sinks for CO2 and are sources of CH4 for the atmosphere. However, drainage may transform these ecosystems into net sources of CO2, but the increase in growth of the tree stand and consequent fixation of carbon after drainage may be expected to have a compensating effect. The post‐drainage change in the peat carbon stores was determined using a method based on the bulk density and carbon content profiles measured along a transect running from the undrained part to the drained part of the mire. The difference between the undrained and drained peat carbon stores, averaged over the 30 yr period after drainage, indicated that the accumulation of carbon had been 35 g C m‐2 yr‐1 greater in the undrained site. As the long‐term accumulation rate of the undrained site had been 21 g C m‐2 yr‐1, the drained part had lost 14 g C m‐2 yr‐1 from the pre‐drainage carbon store. Total accumulated biomass in the tree stand was estimated from stem wood development using the growth and yield tabl...