Linking wood density with tree growth and environment: a theoretical analysis based on the motion of water

Authors

  • Michael L. Roderick,

    Corresponding author
    1. Ecosystem Dynamics Group and C. R. C. for Greenhouse Accounting, Research School of Biological Sciences, Institute of Advanced Studies, The Australian National University, Canberra ACT 0200, Australia
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  • Sandra L. Berry

    1. Ecosystem Dynamics Group and C. R. C. for Greenhouse Accounting, Research School of Biological Sciences, Institute of Advanced Studies, The Australian National University, Canberra ACT 0200, Australia
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Author for correspondence: M. L. Roderick Tel: +61 261254020 Fax: +61 261255095 Email:Michael.Roderick@anu.edu.au

Summary

  • • An hydraulic model of a tree stem is presented to help understand how the carbon storage in ecosystems varies with changing environmental conditions.

  • • The model is based on the assumption that a tree stem is a collection of parallel pipes and was used to (qualitatively) predict how the mass concentration of dry matter ([D]) would vary with water temperature (via changes in viscosity), nitrogen supply and atmospheric CO2.

  • • There was qualitative agreement between model predictions and observed gross trends. The model predicted that the flow rate would be relatively insensitive to variations in [D] in angiosperm stems; this was consistent with observations. It is concluded that other factors need to be considered to explain variations in [D] in angiosperm wood. The flow rate of water through gynmosperm stems was predicted to be very sensitive to variations in [D] and the model explained why [D]; decreases with decreases in water temperature, decreases with increases in nitrogen supply and increases with elevated CO2.

  • • The model captured some of the important underlying relations linking water transport with wood density and environment and qualitative testing of the model is recommended.

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