Wood Density Varies More Within Species than Previously Recognized, Global Analysis Shows

This publication examines how wood density varies within and among plant species worldwide, using a large global database to quantify intraspecific variation across tissues and environments. The study is based on data from the most comprehensive wood density collection to date, including over 100,000 records from roughly 16,000 plant species across woody life forms and biomes. It shows that while environmental effects exist, most wood density variation is species-level, making single measurements unreliable and motivating broader, systematic sampling.

Beyond species means – the intraspecific contribution to global wood density variation

By Ezequiel Fabiano, Anja Linstädter, Liana Kindermann et al.

Abstract
Wood density is central for estimating vegetation carbon storage and a plant functional trait of great ecological and evolutionary importance. However, the global extent of wood density variation is unclear, especially at the intraspecific level. We assembled the most comprehensive wood density collection to date, including 109 626 records from 16 829 plant species across woody life forms and biomes (GWDD v.2, available here: doi: 10.5281/zenodo.16919509). Using the GWDD v.2, we explored the sources of wood density variation within individuals, within species and across environmental gradients. Intraspecific variation accounted for c. 15% of overall wood density variation (SD = 0.068 g cm⁻³). Variance was 50% smaller in sapwood than heartwood, and 30% smaller in branchwood than trunkwood. Individuals in extreme environments (dry, hot and acidic soils) had higher wood density than conspecifics elsewhere (+0.02 g cm⁻³, c. 4% of the mean). Intraspecific environmental effects strongly tracked interspecific patterns (r = 0.83) but were 70–80% smaller and varied considerably among taxa. Individual plant wood density was difficult to predict (root mean square error > 0.08 g cm⁻³; single-measurement R² = 0.59). We recommend (1) systematic sampling of multiple individuals and tissues for local applications, and (2) expanded taxonomic coverage combined with integrative models for robust estimates across ecological scales.

Reference

Fabiano, E., Linstädter, A., Kindermann, L., et al. 2026. Beyond species means – the intraspecific contribution to global wood density variation. New Phytologist Link