Evaluation of the tritiated water method for measurement of transpiration in young Pinus taeda L

Journal Article · Mon Mar 01 04:00:00 EST 1982 · For. Sci.; (United States)

OSTI ID:6778749

Luvall, J C ^[1]; Murphy, Jr, C E

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1. Univ. of Georgia, Athens

The tritiated water (HTO) technique was evaluated as a method for measurement of transpiration of young loblolly pine. Twenty-one millicuries of tritium in 3 ml of water were injected into holes drilled at the base of the trees. The transpiration rate was estimated to average 8.3 liters/day per tree for three trees injected in February and 40.4 liters/day for a single tree injected in July. Several methods of collecting the water from the trees for tritium analysis were evaluated. The collection of water by condensation in clear plastic bags sealed around branch tips proved to be a simple, reliable method of collecting water. Difference in the integral tritium activity with distance from the injection site were found. Serious errors in the estimation of transpiration are possible if the difference in tritium activity in the canopy are not taken into account. The activity measured in the water collected nearest the injection point provided good estimation of transpiration when compared to evaporation determined by a soil water balance or by the Penman-Monteith evaporation formula.

• OSTI ID: 6778749
• Journal Information: For. Sci.; (United States), Journal Name: For. Sci.; (United States) Vol. 28:1; ISSN FOSCA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
553001 -- Agriculture & Food Technology-- Tracer Techniques-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
60 APPLIED LIFE SCIENCES
CONIFERS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
OXYGEN COMPOUNDS
PINES
PLANTS
RADIOASSAY
TRACER TECHNIQUES
TRANSPIRATION
TREES
TRITIUM COMPOUNDS
WATER