due to widespread deforestation followed by extreme and extensive land degradation large areas in iceland have limited capacity to stop secondary transport of the tephra by wind and water and the release of massive dust clouds historical records show that prior to human settlement the area in the vicinity of mt hekla was mostly covered by woodlands which stabilised volcanic tephra and pumice and prevented secondary distribution following the settlement forest clearance and intensive grazing started sigurmundsson et al this reduced the resilience of the ecosystem towards deposition of volcanic tephra and sand storms which initiated largescale soil erosion thorarinsdottir etai