Lehnebach et al. review the diverse and multi-disciplinary uses of the Pipe Model Theory (PMT) and associated properties, and scrutinize their validity in the light of current anatomical and physiological knowledge. They discuss applications and modifications of the PMT theory in the context of biomass allocation and hydraulic models, with a particular focus on its extensive use in functional-structural plant modelling.
Lehnebach et al. conclude that the PMT is not valid as a universal rule: in particular, the suggested ratio between sapwood and leaf area is generally not constant, varying not only between species, but also with ontogeny and environmental conditions. Nevertheless they argue that it continues to be useful as a first approximation for relevant functional-structural processes at appropriate scales.
This paper is part of the Annals of Botany Special Issue on Functional-Structural Plant Growth Modelling. It will be free access until June 2018, then available only to subscribers until April 2019 when it will be free access again.