Physiological girdling of pine trees via phloem chilling: proof of concept
- Author(s): Johnsen, Kurt; Maier, Chris; Sanchez, Felipe; Anderson, Peter; Butnor, John; Waring, Richard; Linder, Sune
- Date: 2007
- Source: Plant, Cell and Environment, Vol. 30: 128-134
- Station ID: --
Quantifying below-ground carbon (C) allocation is particularly difficult as methods usually disturb the root mycorrhizalsoil continuum. We reduced C allocation below ground of loblolly pine trees by: (1) physically girdling trees and (2) physiologically girdling pine trees by chilling the phloem. Chilling reduced cambium temperatures by approximately 18 °C. Both methods rapidly reduced soil CO2 efflux, and after approximately 10 days decreased net photosynthesis (Pn), the latter indicating feedback inhibition. Chilling decreased soil-soluble C, indicating that decreased soil CO2 efflux may have been mediated by a decrease in root C exudation that was rapidly respired by microbes. These effects were only observed in late summer/early autumn when above-ground growth was minimal, and not in the spring when above-ground growth was rapid. All of the effects were rapidly reversed when chilling was ceased. In fertilized plots, both chilling and physical girdling methods reduced soil CO2 efflux by approximately 8%. Physical girdling reduced soil CO2 efflux by 26% in non-fertilized plots. This work demonstrates that phloem chilling provides a non-destructive alternative to reducing the movement of recent photosynthate below the point of chilling to estimate C allocation below ground on large trees.
You can order print copies of our publications through our Publication Ordering System. Make a note of the publication you wish to request, and visit our Publication Order Site.
- We recommend that you 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.
- Our on-line publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact the SRS Webmaster if you notice any errors which make this publication unuseable.
- To view this article get the latest version of the Adobe Acrobat Reader.