Deviation from symmetrically self-similar branching in trees predicts altered hydraulics, mechanics, light interception and metabolic scaling

Duncan D. Smith, John S. Sperry, Brian Enquist, Van M. Savage, Katherine A. Mcculloh, Lisa P. Bentley

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Summary: The West, Brown, Enquist (WBE) model derives symmetrically self-similar branching to predict metabolic scaling from hydraulic conductance, K, (a metabolism proxy) and tree mass (or volume, V). The original prediction was K∝V0.75. We ask whether trees differ from WBE symmetry and if it matters for plant function and scaling. We measure tree branching and model how architecture influences K, V, mechanical stability, light interception and metabolic scaling. We quantified branching architecture by measuring the path fraction, Pf: mean/maximum trunk-to-twig pathlength. WBE symmetry produces the maximum, Pf = 1.0. We explored tree morphospace using a probability-based numerical model constrained only by biomechanical principles. Real tree Pf ranged from 0.930 (nearly symmetric) to 0.357 (very asymmetric). At each modeled tree size, a reduction in Pf led to: increased K; decreased V; increased mechanical stability; and decreased light absorption. When Pf was ontogenetically constant, strong asymmetry only slightly steepened metabolic scaling. The Pf ontogeny of real trees, however, was 'U' shaped, resulting in size-dependent metabolic scaling that exceeded 0.75 in small trees before falling below 0.65. Architectural diversity appears to matter considerably for whole-tree hydraulics, mechanics, photosynthesis and potentially metabolic scaling. Optimal architectures likely exist that maximize carbon gain per structural investment.

Original languageEnglish (US)
Pages (from-to)217-229
Number of pages13
JournalNew Phytologist
Volume201
Issue number1
DOIs
StatePublished - Jan 2014

Fingerprint

Mechanics
mechanics
branching
fluid mechanics
Light
Accidental Falls
photostability
Photosynthesis
Proxy
tree trunk
ontogeny
Carbon
photosynthesis
metabolism
prediction
carbon

Keywords

  • Branching symmetry
  • Euler buckling
  • Hydraulic architecture
  • Light interception
  • Metabolic scaling theory
  • Plant allometry
  • West Brown and Enquist

ASJC Scopus subject areas

  • Plant Science
  • Physiology

Cite this

Deviation from symmetrically self-similar branching in trees predicts altered hydraulics, mechanics, light interception and metabolic scaling. / Smith, Duncan D.; Sperry, John S.; Enquist, Brian; Savage, Van M.; Mcculloh, Katherine A.; Bentley, Lisa P.

In: New Phytologist, Vol. 201, No. 1, 01.2014, p. 217-229.

Research output: Contribution to journalArticle

Smith, Duncan D. ; Sperry, John S. ; Enquist, Brian ; Savage, Van M. ; Mcculloh, Katherine A. ; Bentley, Lisa P. / Deviation from symmetrically self-similar branching in trees predicts altered hydraulics, mechanics, light interception and metabolic scaling. In: New Phytologist. 2014 ; Vol. 201, No. 1. pp. 217-229.
@article{0302c02edc9e420e80777a28de4b81fd,
title = "Deviation from symmetrically self-similar branching in trees predicts altered hydraulics, mechanics, light interception and metabolic scaling",
abstract = "Summary: The West, Brown, Enquist (WBE) model derives symmetrically self-similar branching to predict metabolic scaling from hydraulic conductance, K, (a metabolism proxy) and tree mass (or volume, V). The original prediction was K∝V0.75. We ask whether trees differ from WBE symmetry and if it matters for plant function and scaling. We measure tree branching and model how architecture influences K, V, mechanical stability, light interception and metabolic scaling. We quantified branching architecture by measuring the path fraction, Pf: mean/maximum trunk-to-twig pathlength. WBE symmetry produces the maximum, Pf = 1.0. We explored tree morphospace using a probability-based numerical model constrained only by biomechanical principles. Real tree Pf ranged from 0.930 (nearly symmetric) to 0.357 (very asymmetric). At each modeled tree size, a reduction in Pf led to: increased K; decreased V; increased mechanical stability; and decreased light absorption. When Pf was ontogenetically constant, strong asymmetry only slightly steepened metabolic scaling. The Pf ontogeny of real trees, however, was 'U' shaped, resulting in size-dependent metabolic scaling that exceeded 0.75 in small trees before falling below 0.65. Architectural diversity appears to matter considerably for whole-tree hydraulics, mechanics, photosynthesis and potentially metabolic scaling. Optimal architectures likely exist that maximize carbon gain per structural investment.",
keywords = "Branching symmetry, Euler buckling, Hydraulic architecture, Light interception, Metabolic scaling theory, Plant allometry, West Brown and Enquist",
author = "Smith, {Duncan D.} and Sperry, {John S.} and Brian Enquist and Savage, {Van M.} and Mcculloh, {Katherine A.} and Bentley, {Lisa P.}",
year = "2014",
month = "1",
doi = "10.1111/nph.12487",
language = "English (US)",
volume = "201",
pages = "217--229",
journal = "New Phytologist",
issn = "0028-646X",
publisher = "Wiley-Blackwell",
number = "1",

}

TY - JOUR

T1 - Deviation from symmetrically self-similar branching in trees predicts altered hydraulics, mechanics, light interception and metabolic scaling

AU - Smith, Duncan D.

AU - Sperry, John S.

AU - Enquist, Brian

AU - Savage, Van M.

AU - Mcculloh, Katherine A.

AU - Bentley, Lisa P.

PY - 2014/1

Y1 - 2014/1

N2 - Summary: The West, Brown, Enquist (WBE) model derives symmetrically self-similar branching to predict metabolic scaling from hydraulic conductance, K, (a metabolism proxy) and tree mass (or volume, V). The original prediction was K∝V0.75. We ask whether trees differ from WBE symmetry and if it matters for plant function and scaling. We measure tree branching and model how architecture influences K, V, mechanical stability, light interception and metabolic scaling. We quantified branching architecture by measuring the path fraction, Pf: mean/maximum trunk-to-twig pathlength. WBE symmetry produces the maximum, Pf = 1.0. We explored tree morphospace using a probability-based numerical model constrained only by biomechanical principles. Real tree Pf ranged from 0.930 (nearly symmetric) to 0.357 (very asymmetric). At each modeled tree size, a reduction in Pf led to: increased K; decreased V; increased mechanical stability; and decreased light absorption. When Pf was ontogenetically constant, strong asymmetry only slightly steepened metabolic scaling. The Pf ontogeny of real trees, however, was 'U' shaped, resulting in size-dependent metabolic scaling that exceeded 0.75 in small trees before falling below 0.65. Architectural diversity appears to matter considerably for whole-tree hydraulics, mechanics, photosynthesis and potentially metabolic scaling. Optimal architectures likely exist that maximize carbon gain per structural investment.

AB - Summary: The West, Brown, Enquist (WBE) model derives symmetrically self-similar branching to predict metabolic scaling from hydraulic conductance, K, (a metabolism proxy) and tree mass (or volume, V). The original prediction was K∝V0.75. We ask whether trees differ from WBE symmetry and if it matters for plant function and scaling. We measure tree branching and model how architecture influences K, V, mechanical stability, light interception and metabolic scaling. We quantified branching architecture by measuring the path fraction, Pf: mean/maximum trunk-to-twig pathlength. WBE symmetry produces the maximum, Pf = 1.0. We explored tree morphospace using a probability-based numerical model constrained only by biomechanical principles. Real tree Pf ranged from 0.930 (nearly symmetric) to 0.357 (very asymmetric). At each modeled tree size, a reduction in Pf led to: increased K; decreased V; increased mechanical stability; and decreased light absorption. When Pf was ontogenetically constant, strong asymmetry only slightly steepened metabolic scaling. The Pf ontogeny of real trees, however, was 'U' shaped, resulting in size-dependent metabolic scaling that exceeded 0.75 in small trees before falling below 0.65. Architectural diversity appears to matter considerably for whole-tree hydraulics, mechanics, photosynthesis and potentially metabolic scaling. Optimal architectures likely exist that maximize carbon gain per structural investment.

KW - Branching symmetry

KW - Euler buckling

KW - Hydraulic architecture

KW - Light interception

KW - Metabolic scaling theory

KW - Plant allometry

KW - West Brown and Enquist

UR - http://www.scopus.com/inward/record.url?scp=84888286817&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84888286817&partnerID=8YFLogxK

U2 - 10.1111/nph.12487

DO - 10.1111/nph.12487

M3 - Article

C2 - 24102299

AN - SCOPUS:84888286817

VL - 201

SP - 217

EP - 229

JO - New Phytologist

JF - New Phytologist

SN - 0028-646X

IS - 1

ER -