Does water transport scale universally with tree size?

Abstract

Summary 1.We employed standardized measurement techniques and protocols to describe the size dependence of whole-tree water use and cross-sectional area of conducting xylem (sapwood) among several species of angiosperms and conifers. 2. The results were not inconsistent with previously proposed 3/4-power scaling of water transport with estimated above-ground biomass. However, for a given size, angiosperms transported considerably greater quantities of water than conifers. 3. In the angiosperms studied, the scaling of water transport with sapwood area, stem diameter and above-ground biomass was best described by sigmoid functions rather than a power function, consistent with the previously reported size dependence of other processes such as growth. 4. At least three distinct species groupings for relationships between sapwood area and stem basal area were observed. Scaling of sapwood area with stem radius was well described by a power function of the form Y = Y 0 X b . However, exponents obtained for two of the three species groups differed significantly from a recently proposed theoretical value of 2·33.

Allométrie du bois de cœur et de l’aubier pour sept espèces d’arbres tempérées chinoises

“…Our data showed the exponents varied from 1.32 for the Dahurian larch to 2.19 for the cork-tree (Tab. V), supporting the notion proposed by Meinzer et al (2005) but with a wider exponent range. This conclusion seems plausible because there are divergences in morphological and physiological properties of water conducting system for diverse species (Hacke et al, 2006).…”

“…2.33). However, Meinzer et al (2005) found that the exponents could be divided into at least three distinct species groupings, varying from 1.42 to 1.90 for the 25 temperate and tropical species investigated. Our data showed the exponents varied from 1.32 for the Dahurian larch to 2.19 for the cork-tree (Tab.…”

“…A power function model for scaling SA from stem diameter has been widely accepted, but the universal exponent of 7/3 of the power function proposed by Enquist (2002) has been challenged. For example, Meinzer et al (2005) investigated 25 temperate and tropical species, and reported that the exponents varied from 1.42 to 1.90 depending upon species groups. Clearly, more measurements on sapwood allometry for diverse tree species are needed for validating the theoretical model (Enquist, 2002).…”

Extensions and evaluations of a general quantitative theory of forest structure and dynamics

“…Prediction: The total energy and resource flux of all stems within a size class is independent of plant size when binned linearly with respect to stem radius. As shown previously, both theoretically (16) and empirically (15,28), the xylem flux of a tree, Q k , scales as Q k ϰ r k 2 ϰ m k 3/4 . When combined with the inverse square law for the number of trees in a bin, ⌬n k ϰ r k Ϫ2 ϰ m k Ϫ3/4 , this predicts that the total resource flux per unit area per size class, is invariant with respect to tree size.…”

Environment and tree size controlling stem sap flux in a perhumid tropical forest of Central Sulawesi, Indonesia

“…Various other authors have also reported a positive tree size-water consumption relationship for tropical species referring either to tree height or DBH (e.g. Andrade et al 1998, with tree height; Meinzer et al 2005, The relationship between E and vapour pressure deficit (D mean , kPa) followed an exponential form for all tree height classes. The relationship between E and solar radiation (R, MJ m −2 day −1 ) was better fitted to a first-order polynomial in all tree height classes.…”