1Vegetation cover mediates a number of important geomorphological processes. 2 However, the effect of different vegetation types on the retention of fine aeolian 3 sediment is poorly understood. We investigated this phenomenon, using the retention 4 of fine, pyroclastic material (tephra) from the 2011 eruption of the Grímsvötn volcano, 5Iceland, as a case study. We set out to quantify structural variation in different 6 vegetation types and to relate structural metrics to the thickness of recently deposited 7 volcanic ash layers in the sedimentary section. We utilised a combination of vegetation 8and soil surveys, along with photogrammetric analysis of vegetation structure. We 9 found that indices of plant community composition were a poor proxy for vegetation 10 structure and were largely unrelated to tephra thickness. However, structural metrics, 11 derived from photogrammetric analysis, were clearly related to variations in tephra 12 layer thickness at a landscape scale and tephra layers under shrub patches were 13 significantly thicker than those outside the shrub canopy. We therefore concluded that 14 a) vegetation cover was a critical factor in the retention of fine aeolian sediment for 15 deposit depths up to few centimetres and b) structural variation in vegetation cover 16 played a major role in determining the configuration of tephra deposits in the 17 sedimentary section. These findings have implications for the analysis of ancient 18 volcanic eruptions and archaeological/palaeoenvironmental reconstructions based on 19