DOI: 10.5061/dryad.dfn2z359b
title: Data from: Scaling of leaf area with biomass in trees reconsidered: Constant metabolically active sapwood volume per unit leaf area with height growth

description: Hypoallometric (slope&lt;1) scaling between metabolic rate and body
 mass is often regarded as near-universal across organisms. However, there
 are compelling reasons to question hypoallometric scaling in woody plants,
 where metabolic rate=leaf area. This leaf area must provide carbon to the
 metabolically active sapwood volume (VMASW). Within populations of a
 species, variants in which VMASW increases per unit leaf area with height
 growth (e.g. ⅔ or ¾ scaling) would have proportionally less carbon for
 growth and reproduction as they grow taller. Therefore, selection should
 favor individuals in which, as they grow taller, leaf area scales
 isometrically with shoot VMASW (slope=1). Using tetrazolium staining, we
 measured total VMASW and total leaf area (LAtot) across 22 individuals of
 Ricinus communis and confirmed that leaf area scales isometrically with
 VMASW, and that VMASW is much smaller than total sapwood volume. With the
 potential of the LAtot-VMASW relationship to shape factors as diverse as
 the crown area-stem diameter relationship, conduit diameter scaling,
 reproductive output, and drought-induced mortality, our work suggests that
 the notion that sapwood increases per unit leaf area with height growth
 requires revision.
description: # Scaling of leaf area with biomass in trees reconsidered: constant
 metabolically active sapwood volume per unit leaf area with height growth
 A brief summary of dataset contents, in the context of the methodology
 followed, is given below. * We tested leaf area-metabolically active
 sapwood volume relationship in *Ricinus communis* L.(Euphorbiaceae). We
 used the tetrazolium test to estimate volume of metabolically active
 sapwood volume. We cut each individual into segments 30 or 50 cm long (50
 cm for plants above 2 m tall), and we measured the length, basal diameter,
 and apical diameter of each segment. 2 cm thick discs from each segment
 were placed into a solution of 2,3,5-triphenyl-2H- tetrazolium chloride
 (TTC), see Material and Methods for details of protocol. The TTC stain
 identifies the regions of metabolically active xylem and colours them red.
 * Estimating metabolically active sapwood area and volume - ImageJ 1.52a
 (Schneider et al., 2012) was used to calculate the total area of
 metabolically active sapwood for each stem sample photographed with a
 scale. To calculate the metabolically active sapwood volume of the
 whole-plant, see Material and Methods for details. To provide a comparison
 with traditional estimates of sapwood volume, we also calculated the total
 xylem volume of each individual. * Estimating leaf area - For each
 individual, we scanned all leaves using WinFOLIA 2011a (Regent Instruments
 Inc., Canada) and calculated total leaf area. ## Description of the data
 and file structure There are two excel files that has been shared. The
 spreadsheet file named "MetabloicScaling_Ricinus" contains all
 *Ricinus* data collected. The spreadsheet file named
 "Scaling_Comparison" has *Ricinus*, *Sequoia*, *Sequoiadendron*,
 and *Eucalyptus* data. Data on the plant traits studied could be retrieved
 as follows: ### **MetabloicScalingRicinus\_data**\_Data * *Individual
 No.*: Identifier for *Ricinus* individual accession number * *Height
 (cm)*: Plant height of the *Ricinus* individual (cm) * *Dia.base (cm)*:
 Diameter of the stem at the base (cm) * *leaf area (la) (cm2)*: Total leaf
 area of the plant individual (cm2) * *Active.xylem.vol.4hrs (cm3)*:
 Metabolically active xylem was calculated (cm3); NA indicates that we did
 not measure the metabolic active xylem volume for that individual. *
 *Active Xylem Area of Stem at Base (4 hr) (cm2)*: Of the stem cross
 section at base, the metabolically active xylem area present (cm2); NA
 indicates that we did not measure the metabolic active xylem area of stem
 at base for that individual. * *Total Xylem Volume (cm3)*: The sum-total
 of all volumes of xylem measured from all the stem segments of the
 individual plant (cm3); NA indicates that we did not measure the total
 xylem volume of the stem for that individual. * *Total Stem Volume (cm3)*:
 The sum-total of all volumes of stem measured from all cylindrical stem
 segments of the individual plant (cm3); NA indicates that we did not
 measure the total stem volume for that individual. * *Lateral.stem.surface
 (cm2)*: Total stem surface area of the individual plant (cm2); NA
 indicates that we did not measure the lateral stem surface area for that
 individual. * *LA.plus.stem-surface-area (cm2)*: Summation of total leaf
 area and total stem surface area of the individual plant (cm2); NA
 indicates that we did not measure the sum of total leaf area and total
 stem surface area for that individual. * *Tot Sapwood area of Stem at base
 (cm2)*: Total xylem area at the base of the stem for the individual; NA
 indicates that we did not measure the total sapwood area of the stem at
 base for that individual. ### **Scaling\_Comparison**\_Comparison To
 statistically compare our metabolic staining method data with traditional
 method of sapwood volume measurements from large trees, we used published
 data of sapwood volume and leaf area from among the largest trees on
 Earth, *Sequoia sempervirens*, *Sequoiadendron giganteum*, and *Eucalyptus
 regnans* from Sillett et al. (2010, 2015). Blank cells show
 unmeasured/missing values. Data on the plant traits compared between
 species and methods could be retrieved as follows: * *Genus*: Identifies
 the different plant genera studied, namely, *Ricinus*, *Sequoia*,
 *Sequoiadendron*, and *Eucalyptus*. * *Individual No.*: Identifies the
 number of the individuals of *Ricinus*, *Sequoia*, *Sequoiadendron*, and
 *Eucalyptus* with a unique accession. * *leaf area (cm2)*: The total leaf
 area of each individual plant in cm square, where WinFOLIA 2011a (Regent
 Instruments Inc., Canada) was used to determine the sum-total of all
 leaves in the plant individual. * *volume (cm3)*: The volume of the total
 stem or the metabolically active xylem/sapwood, or the total xylem of the
 individual plant measured in cubic cm. * *Identifier*: This column
 identifies the type of volume measured in the previous column, namely,
 /volume (cm3) * *Comparison*: This identifies whether it is a
 inter-specific comparison or a intra-specific comparison. If
 inter-specific then TRUE else FALSE. ## Sharing/Access information Some
 data was derived from the following sources: * We compared our results
 from Ricinus with published data of traditional measurements of sapwood
 volume from large trees. We added published data of sapwood volume and
 leaf area from among the largest trees on Earth, namely, *Sequoia
 sempervirens*, *Sequoiadendron giganteum*, and *Eucalyptus regnans*, using
 data from Sillett et al. (2010, 2015). Sillett et al. measured sapwood
 based on traditional color estimation, and measured leaf area. Total leaf
 area was not measured directly, but instead subsamples were measured and
 area extrapolated to whole crowns. * Sillett SC, Van Pelt R, Koch GW,
 Ambrose AR, Carroll AL, Antoine ME, Mifsud BM. 2010. Increasing wood
 production through old age in tall trees. Forest Ecology and Management
 259, 976–994. * Sillett SC, Van Pelt R, Kramer RD, Carroll AL, Koch GW.
 2015. Biomass and growth potential of Eucalyptus regnans up to 100m tall.
 Forest Ecology and Management 348, 78–91. * We complemented the Eucalyptus
 data with the addition of 6 smaller individuals of *Eucalyptus
 camaldulensis* to expand the range of sizes of individuals. We used
 similar methods for these individuals as for *Ricinus*.