Sound Research WIKINDX
Sound Research WIKINDX |
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Zweifel, R., & Zeugin, F. (2008). Ultrasonic acoustic emissions in drought-stressed trees – more than signals from cavitation? The New Phytologist, 179(4), 1070–1079. Added by: Mark Grimshaw-Aagaard (2/28/25, 3:16 AM) Last edited by: Mark Grimshaw-Aagaard (2/28/25, 3:19 AM) |
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| Resource type: Journal Article Language: en: English Peer reviewed DOI: 10.1111/j.1469-8137.2008.02521.x ID no. (ISBN etc.): 1469-8137 BibTeX citation key: Zweifel2008 Email resource to friend View all bibliographic details  |
Categories: General Keywords: Bioacoustics, Plants, Ultrasound Creators: Zeugin, Zweifel Collection: The New Phytologist |
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| Abstract |
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Ultrasonic acoustic emission (UAE) in trees is often related to collapsing water columns in the flow path as a result of tensions that are too strong (cavitation). However, in a decibel (dB) range below that associated with cavitation, a close relationship was found between UAE intensities and stem radius changes. UAE was continuously recorded on the stems of mature field-grown trees of Scots pine (Pinus sylvestris) and pubescent oak (Quercus pubescens) at a dry inner-Alpine site in Switzerland over two seasons. The averaged 20-Hz records were related to microclimatic conditions in air and soil, sap-flow rates and stem-radius fluctuations detrended for growth (Delta W). Within a low-dB range (27 +/- 1 dB), UAE regularly increased and decreased in a diurnal rhythm in parallel with DeltaW on cloudy days and at night. These low-dB emissions were interrupted by UAE abruptly switching between the low-dB range and a high-dB range (36 +/- 1 dB) on clear, sunny days, corresponding to the widely supported interpretation of UAE as sound from cavitations. It is hypothesized that the low-dB signals in drought-stressed trees are caused by respiration and/or cambial growth as these physiological activities are tissue water-content dependent and have been shown to produce courses of CO(2) efflux similar to our courses of Delta W and low-dB UAE.
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