Physics in Perspective

, Volume 15, Issue 3, pp 320–358

The Theory of the Rise of Sap in Trees: Some Historical and Conceptual Remarks


DOI: 10.1007/s00016-013-0117-1

Cite this article as:
Brown, H.R. Phys. Perspect. (2013) 15: 320. doi:10.1007/s00016-013-0117-1


The ability of trees to suck water from roots to leaves, sometimes to heights of over a hundred meters, is remarkable given the absence of any mechanical pump. In this study I deal with a number of issues, of both a historical and conceptual nature, in the orthodox Cohesion-Tension (CT) theory of the ascent of sap in trees. The theory relies chiefly on the exceptional cohesive and adhesive properties of water, the structural properties of trees, and the role of evaporation (“transpiration”) from leaves. But it is not the whole story. Plant scientists have been aware since the inception of the theory in the late 19th century that further processes are at work in order to “prime” the trees, the main such process – growth itself – being so obvious to them that it is often omitted from the story. Other factors depend largely on the type of tree, and are not always fully understood. For physicists, in particular, it may be helpful to see the fuller picture, which is what I attempt to provide in nontechnical terms.


Eugen AskenasyJosef BöhmEdwin B. CopelandPierre CruiziatFrancis DarwinHenry H. DixonGeorge Francis FitzGeraldStephen HalesTaco Hajo van den HonertJohn JolyJohn A. MilburnPark S. NobelJ.J. OertliWilliam F. PicardJohn S. SperryErnst SteudleEduard StrasburgerMelvin T. TyreeMartin H. Zimmermanncohesion-tension theoryrise of saptranspirationcapillaritycavitationnegative xylem pressurehydraulic architectureglobal warmingclimate changehistory of biophysics

Copyright information

© Springer Basel 2013

Authors and Affiliations

  1. 1.Faculty of PhilosophyUniversity of OxfordOxfordUK