Skip to main content
U.S. flag

An official website of the United States government

Dynamics of stem water uptake among isohydric and anisohydric species experiencing a severe drought

Author(s):

Koong Yi
Danilo Dragoni
Richard P. Phillips
Kimberly A. Novick

Year:

2017

Publication type:

Scientific Journal (JRNL)

Primary Station(s):

Northern Research Station

Source:

Tree Physiology.

Description

Predicting the impact of drought on forest ecosystem processes requires an understanding of trees' species-specific responses to drought, especially in the Eastern USA, where species composition is highly dynamic due to historical changes in land use and fire regime. Here, we adapted a framework that classifies trees' water-use strategy along the spectrum of isohydric to anisohydric behavior to determine the responses of three canopy-dominant species to drought. We used a collection of leaf-level gas exchange, tree-level sap flux and stand-level eddy covariance data collected in south-central Indiana from 2011 to 2013, which included an unusually severe drought in the summer of 2012. Our goal was to assess how patterns in the radial profile of sap flux and reliance on hydraulic capacitance differed among species of contrasting water-use strategies. In isohydric species (Quercus alba L. and Quercus rubra L.), which included sugar maple (Acer saccharum Marsh.) and tulip poplar (Liriodendron tulipifera L.), we found that the sap flux in the outer xylem experienced dramatic declines during drought, but sap flux at inner xylem was buffered from reductions in water availability. In contrast, for anisohydric oak species, we observed relatively smaller variations in sap flux during drought in both inner and outer xylem, and higher nighttime refilling when compared with isohydric species. This reliance on nocturnal refilling, which occurred coincident with a decoupling between leaf- and tree-level water-use dynamics, suggests that anisohydric species may benefit from a reliance on hydraulic capacitance to mitigate the risk of hydraulic failure associated with maintaining high transpiration rates during drought. In the case of both isohydric and anisohydric species, our work demonstrates that failure to account for shifts in the radial profile of sap flux during drought could introduce substantial bias in estimates of tree water use during both drought and non-drought periods.

Citation

Yi, Koong; Dragoni, Danilo; Phillips, Richard P.; Roman, D. Tyler; Novick, Kimberly A. 2017. Dynamics of stem water uptake among isohydric and anisohydric species experiencing a severe drought. Tree Physiology. 37: 1379-1392. http://dx.doi.org/10.10.93/treephys/tpw126.

Cited

Publication Notes

  • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
  • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
https://www.fs.usda.gov/treesearch/pubs/53476