Testing the metabolic theory of ecology

An argument that critical evaluation of MTE also requires strong tests of both its theoretical foundations and simplifying assumptions. To this end, we synthesise available information and find that MTE’s original derivations require additional assumptions to obtain the full scope of attendant predictions.

Price, C.A. et al.

Testing the Metabolic Scaling Theory of tree growth

Metabolic Scaling Theory (MST) predicts a ‘universal scaling law’ of tree growth. Proponents claim that MST has strong empirical support: the size-dependent growth curves of 40 out of 45 species in a Costa Rican forest have scaling exponents indistinguishable from the MST prediction. This paper shows the Costa Rican data has been misinterpreted. Using Standardized MajorAxis (SMA) line-fitting to estimate scaling exponents, we find that four out of five species represented have scaling exponents that deviate significantly from the prediction.

Coomes, D.A.; Allen, R.B.

Scaling of xylem vessels and veins within oak leaves

An examination of the scaling of the leaf xylem in ten temperate oak species to test general models of plant vascular architecture, based on scaling of pipe diameters in order to minimize hydraulic resistance within the xylem, which have neglected to consider the variations in leaf hydraulic properties.

Coomes, D.A.; Heathcote, S.; Godfrey, E.R.; Shepherd, J.J.; Sack, L.

Scaling of tree vascular transport systems along gradients of nutrient supply and altitude

Investigating whether trees growing at high altitude or on nutrient-depleted soils prioritise survival over minimising hydraulic resistance by narrowing xylem distally or of their vascular systems would be structured differently from those of trees growing under more benign conditions. Conduits were observed to narrow towards the periphery of vascular system within all members of all species investigated, and scaling relation-ships were indistinguishable across a range of environments.

Coomes, D.A.; Jenkins, K.L.; Cole L.E.S.

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