Compaction rates of sediments or volcaniclastic material are needed to reconstruct original thickness of a bed,which in turn is required to reconstruct subsidence rates,sea-level rise,or in the case of volcaniclastic,the location or direction of the eruption site.The knowledge of compaction rates can also aid in the reconstruction of deformed fossils.The known shape of deformed fossils can allow the determination of the compaction they experienced.Here we report the compaction rate in an early Permian volcanic tuff from Wuda,Inner Mongolia,determined from the deformation of standing tree fern stems of known anatomy.The compaction rate has been found to be 0.56 in this case,indicating that 44% of original thickness remains. Compaction rates of sediments or volcaniclastic materials are needed to reconstruct original thickness of a bed, which in turn is required to reconstruct subsidence rates, sea-level rise, or in the case of volcaniclastic, the location or direction of the eruption site. Knowledge of compaction rates can also aid in the reconstruction of deformed fossils. The known shape of deformed fossils can allow the determination of the compaction they experienced. He we we report the compaction rate in an early permian volcanic tuff from Wuda, Inner Mongolia, determined from the deformation of standing tree fern stems of known anatomy.The compaction rate has been found to be 0.56 in this case, indicating that 44% of original thickness remains.