Data from: Scaling of leaf area with biomass in trees reconsidered: Constant metabolically active sapwood volume per unit leaf area with height growth
Data files
May 10, 2024 version files 41.15 KB
Abstract
Hypoallometric (slope<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.
README: 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.