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Instrumental Method for Reducing Error in Compression-Derived Measurements of Rainfall Interception for Individual Trees
Hydrological Sciences Journal (2011)
  • John T. Van Stan, II, Georgia Southern University
  • Matthew T. Jarvis
  • Delphis F. Levia, University of Delaware
  • Jan Friesen
Abstract

This technical note presents an instrumental method for the precise and timely installation of mechanical displacement sensors to investigate stem compression and relaxation associated with whole-tree rainwater loading and evaporation, respectively. We developed this procedure in response to the conclusions of Friesen et al. (2008), which called for the development of a precision mounting method for strain sensors on inherently-irregular trunk cross-sections so that rainfall interception, storage and evaporation may be distinguished from other strain-related phenomena. To supply precise sensor installation locations, high-resolution trunk profiles are generated using the LaserBarkTM automated tree measurement system. These scans are utilized to approximate the location of neutral bending axes. A routine then instructs a mobile rangefinder along the cross-section to optically indicate exact positioning for strain sensors over the bending axes. As imprecise sensor placement linearly increases error and diminishes signal-to-noise ratio, this automated installation routine is designed to remove significant distortions created by wind throw, off-centre loading within unevenly-distributed canopies, and human error that can lead to erroneous measurements of rainfall interception.

Keywords
  • forest hydrology,
  • interception,
  • stem compression,
  • mechanical displacement sensor,
  • LaserBark™
Disciplines
Publication Date
2011
Citation Information
John T. Van Stan, Matthew T. Jarvis, Delphis F. Levia and Jan Friesen. "Instrumental Method for Reducing Error in Compression-Derived Measurements of Rainfall Interception for Individual Trees" Hydrological Sciences Journal Vol. 56 Iss. 6 (2011)
Available at: http://works.bepress.com/john_vanstan/10/