Study
Global convergence in the vulnerability of forests to drought
Choat, B.; Jansen, S.; Brodribb, T. J.; Cochard, H.; Delzon, S.; Bhaskar, R.; Bucci, S. J.; Feild, T. S.; Gleason, S. M.; Hacke, U. G.; Jacobsen, A. L.; Lens, F.; Maherali, H.; Martínez-Vilalta, J.; Mayr, S.; Mencuccini, M.; Mitchell, P. J.; Nardini, A.; Pittermann, J.; Pratt, R. B.; Sperry, J. S.; Westoby, M.; Wright, I. J.; Zanne, A. E.
Nature, 2012
Published measurements of how much tension a species can hold before its xylem loses conductivity were assembled for hundreds of forest species, and compared against the lowest tensions those species actually experience in the field. The gap between the two is the safety margin.
- Studied in
- Tracheophyta
- Sample size
- 226 species from 81 sites across the world
Safety margins are narrow almost everywhere, and — the surprise — they are narrow in wet forests as well as dry ones. Species from rainforests operate about as close to their hydraulic limit as species from deserts do.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Forests across biomes converge on narrow hydraulic safety margins, so drought-induced decline is a global rather than a dryland risk.
How NatureHQ reads it
Two useful things for a reader. First, it explains why drought kills trees in places nobody thinks of as dry: a rainforest tree has built its plumbing for the water it usually gets, and a rare dry year takes it past a limit it was never far from. Second, it puts a number on the trade-off that shapes wood anatomy — a conduit wide enough to be fast is a conduit close enough to failing, and every species has already made that bet.
- Compiled from measurements made by many groups using several methods, some of which have since been questioned.
- A narrow margin is a statement about risk, not a prediction that a given tree will die.
- Measurements are mostly of branches; roots and trunks may behave differently.
What this study is used for on NatureHQ
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Published by: Nature PortfolioPublished in a Nature Portfolio journal.
This reference was resolved automatically against Crossref on 2026-08-30.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-30.