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A method for measuring radial differences in water content of intact tree stems by attenuation of gamma radiation
Author(s) -
EDWARDS W. R. N.,
JARVIS P. G.
Publication year - 1983
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/1365-3040.ep11587650
Subject(s) - attenuation , radiation , water content , homogeneity (statistics) , tree (set theory) , content (measure theory) , mathematics , gamma ray , physics , optics , computational physics , analytical chemistry (journal) , chemistry , mathematical analysis , nuclear physics , statistics , geology , geotechnical engineering , chromatography
. A technique is described for the nondestructive measurement of water content variations in the stems of trees. The density of intact tree stems in the forest was estimated using attenuation of gamma radiation. Water content was calculated after subsequent derivation of the volume fraction of solid matrix. A radial sequence of such measurements was obtained by measuring a sequence of chords, and assuming homogeneity within concentric tori. Analysis of the source of errors showed that the system was a close approximation of an ideal, rigid‐geometry, mono‐energetic source/detector system, with basic precision dependent on the quantity of gamma radiation measured. Correlation coefficients between the gamma‐attenuation technique and subsequent gravimetric estimates of water content for two field experiments reported here were 0.882 and 0.938. The technique was shown to be capable of describing the radial and diurnal variation in water content at two heights in the stem of a 20‐year‐old tree of Pinus contorta .