Magic applied to roof experiments (Risdalsheia, N; Gardsjon, S; Klosterhede, DK) to evaluate the rate of reversibility of acidification following experimentally reduced acid deposition

Soil and stream water responses to 'clean rain' treatments at three roof covered forest ecosystems in Norway, Sweden and Denmark were modelled by the MAGIC model. The model outputs were compared with measured responses. Over the wide span in site conditions among the three sites MAGIC successfully reproduced the observed effects in the 'clean rain' treatments. Seasalt influence caused single year discrepancies but the long term trends were well reproduced. in particular the significant decreases in SO4 output were well reproduced. A simultaneous change in base cation leaching was observed, which in the long run will be the basis for the recovery of these acidified systems. The rate of recovery at the 3 studied sites was very slow.