Acknowledgements
We thank the FRED initiative for sharing trait data about root traits. We thank Walter Judd, Suzanne Koptur, Aaron Hogan and Alan Franck for their insightful comments in previous versions of this manuscript. This research was supported by grants from the US National Science Foundation (DEB-0918240, DEB-0918878, DEB-1549964), US Department of Energy (DE-SC0004335), and the Natural Sciences and Engineering Research Council of Canada (NSERC RGPIN-2018-04620).
sSTATEMENT OF AUTHORSHIP
O.J.V.B., and C.B.B. conceived the idea, O.J.V.B and H.M. collected the data, and O.J.V.B., C.B. and H.M. conducted the statistical analyses and graph configuration. All authors interpreted results and contributed to the writing of the manuscript.