Favouring water transport over mechanical support is thought to be an important adaptative strategy for plants favouring warm and wet polar palaeolatitudes. However, using a novel technique, Jagels et al. (pp. 79-88) show that in the very low density stem of Metasequoia, this strategy can, despite decay-resistant heartwood, sometimes lead to irreversible (plastic) deformation in the xylem of this relict tree.