Study
The global biogeography of roots
Schenk, H. J.; Jackson, R. B.
Ecological Monographs, 2002
Published root profiles — most of them produced by digging up root systems and recording where the roots were — were assembled into a global dataset and analysed against climate, soil and growth form.
- Studied in
- Tracheophyta
- Sample size
- 475 root profiles from published excavations worldwide
Roots are overwhelmingly shallow. Across the dataset about half of all root biomass sat in the top 30 centimetres or so, and the great majority within the top metre, including in woody vegetation. Deep roots exist and matter, but they are a small fraction of the system, and rooting depth tracks water availability and seasonality rather than the size of the plant above.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
Root distribution worldwide is governed principally by water availability and seasonality, with most root biomass concentrated near the surface across biomes.
How NatureHQ reads it
The evidence against the picture almost everyone carries, in which a tree has an underground mirror image of its crown. Excavations find something else: a broad, shallow plate, typically spreading well beyond the edge of the canopy, with a minority of deeper roots doing specific jobs. The reason is not mysterious — roots need oxygen as well as water, and both are near the surface — but it changes what a reader should picture, and it is why the shape of a root system is a climate signal rather than a copy of the tree.
- Excavation destroys what it measures, so sample sizes per site are small and large trees are under-represented.
- Published profiles are biased towards accessible sites and towards species somebody had reason to dig up.
- Records where roots are, not what each root is doing.
Digging up root systems, and finding out where roots actually are
Do a tree’s roots go as deep as the tree is tall?
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Wiley journalsPublished in a Wiley journal.
doi.org/10.1890/0012-9615(2002)072[0311:tgbor]2.0.co;2
This reference was resolved automatically against Crossref and OpenAlex on 2026-08-30.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-08-30.