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Structural adjustments in resprouting trees drive differences in post-fire transpiration.

Publication ,  Journal Article
Nolan, RH; Mitchell, PJ; Bradstock, RA; Lane, PNJ
Published in: Tree physiology
February 2014

Following disturbance many woody species are capable of resprouting new foliage, resulting in a reduced leaf-to-sapwood area ratio and altered canopy structure. We hypothesized that such changes would promote adjustments in leaf physiology, resulting in higher rates of transpiration per unit leaf area, consistent with the mechanistic framework proposed by Whitehead et al. (Whitehead D, Jarvis PG, Waring RH (1984) Stomatal conductance, transpiration and resistance to water uptake in a Pinus sylvestris spacing experiment. Can J For Res 14:692-700). We tested this in Eucalyptus obliqua L'Hér following a wildfire by comparing trees with unburnt canopies with trees that had been subject to 100% canopy scorch and were recovering their leaf area via resprouting. In resprouting trees, foliage was distributed along the trunk and on lateral branches, resulting in shorter hydraulic path lengths. We evaluated measurements of whole-tree transpiration and structural and physiological traits expected to drive any changes in transpiration. We used these structural and physiological measurements to parameterize the Whitehead et al. equation, and found that the expected ratio of transpiration per unit leaf area between resprouting and unburnt trees was 3.41. This is similar to the observed ratio of transpiration per unit leaf area, measured from sapflow observations, which was 2.89 (i.e., resprouting trees had 188% higher transpiration per unit leaf area). Foliage at low heights (<2 m) was found to be significantly different to foliage in the tree crown (14-18 m) in a number of traits, including higher specific leaf area, midday leaf water potential and higher rates of stomatal conductance and photosynthesis. We conclude that these post-fire adjustments in resprouting trees help to drive increased stomatal conductance and hydraulic efficiency, promoting the rapid return of tree-scale transpiration towards pre-disturbance levels. These transient patterns in canopy transpiration have important implications for modelling stand-level water fluxes in forests capable of resprouting, which is frequently done on the basis of the leaf area index.

Duke Scholars

Published In

Tree physiology

DOI

EISSN

1758-4469

ISSN

0829-318X

Publication Date

February 2014

Volume

34

Issue

2

Start / End Page

123 / 136

Related Subject Headings

  • Trees
  • Seasons
  • Plant Transpiration
  • Plant Leaves
  • Plant Biology & Botany
  • Photosynthesis
  • Light
  • Geography
  • Fires
  • Eucalyptus
 

Citation

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Nolan, R. H., Mitchell, P. J., Bradstock, R. A., & Lane, P. N. J. (2014). Structural adjustments in resprouting trees drive differences in post-fire transpiration. Tree Physiology, 34(2), 123–136. https://doi.org/10.1093/treephys/tpt125
Nolan, Rachael H., Patrick J. Mitchell, Ross A. Bradstock, and Patrick N. J. Lane. “Structural adjustments in resprouting trees drive differences in post-fire transpiration.Tree Physiology 34, no. 2 (February 2014): 123–36. https://doi.org/10.1093/treephys/tpt125.
Nolan RH, Mitchell PJ, Bradstock RA, Lane PNJ. Structural adjustments in resprouting trees drive differences in post-fire transpiration. Tree physiology. 2014 Feb;34(2):123–36.
Nolan, Rachael H., et al. “Structural adjustments in resprouting trees drive differences in post-fire transpiration.Tree Physiology, vol. 34, no. 2, Feb. 2014, pp. 123–36. Epmc, doi:10.1093/treephys/tpt125.
Nolan RH, Mitchell PJ, Bradstock RA, Lane PNJ. Structural adjustments in resprouting trees drive differences in post-fire transpiration. Tree physiology. 2014 Feb;34(2):123–136.
Journal cover image

Published In

Tree physiology

DOI

EISSN

1758-4469

ISSN

0829-318X

Publication Date

February 2014

Volume

34

Issue

2

Start / End Page

123 / 136

Related Subject Headings

  • Trees
  • Seasons
  • Plant Transpiration
  • Plant Leaves
  • Plant Biology & Botany
  • Photosynthesis
  • Light
  • Geography
  • Fires
  • Eucalyptus