Title: Detecting defects in conifers with ground penetrating radar: Applications and challenges
Author: Butnor, J. R.; Pruyn, M. L.; Shaw, D. C.; Harmon, M. E.; Mucciardi, A. N.; Ryan, M. G.
Source: Forest Pathology. 39: 309-322.
Description: Our objective was to test ground penetrating radar (GPR) to non-destructively estimate decay volumes in living coniferous trees. GPR is geophysical tool which uses an antenna to propagate short bursts of electromagnetic energy in solid materials and measure the two-way travel time and amplitude of reflected signals. We compared estimates of bole decay from data collected with a SIR 3000 GPR system equipped with a 900 MHz antenna to measurements of decay from stem cross sections and increment cores for three conifer species (Pseudotsuga menziesii, Thuja plicata and Tsuga heterophylla). We found that near-surface decay, air-filled voids and desiccated boles had unique electromagnetic signatures, which could be separated from other defects. GPR successfully estimated the percent area of air-filled cavities and was not significantly different than results from destructive sampling. However, separation of incipient to severe decay from benign reflectors (e.g. moisture gradient between sapwood and heartwood) in conifers was much less diagnostic than with angiosperms. A limited assessment of Acer saccharum showed that GPR has potential to detect defects in angiosperms; however, more research is needed to outline the full range of detectable defects. Based on the trees in this study, the potential for GPR to detect decay-related defects in conifers seems limited. Despite problems detecting decay, reflections originating from the sapwood: heartwood boundary may prove useful to determine thickness of functional sapwood in conifers, but accurate quantification will require further technical development.
Keywords: ground penetrating radar (GPR), conifers, Pseudotsuga menziesii, Thuja plicata, Tsuga heterophylla
View or Print this Publication (484 KB)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
Butnor, J. R.; Pruyn, M. L.; Shaw, D. C.; Harmon, M. E.; Mucciardi, A. N.; Ryan, M. G. 2009. Detecting defects in conifers with ground penetrating radar: Applications and challenges. Forest Pathology. 39: 309-322.
Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility