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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.

The morphology and prevalence of macropores < 10 cm in diameter in forested riparian wetlands is largely unknown despite their importance as a mechanism for preferential flow of contaminants to stream channels. Here, we validate field procedures for detecting and mapping the three‐dimensional structure of near‐surface (15–65 cm deep) lateral macropore networks using non‐invasive ground‐penetrating radar (GPR) technology at a Mid‐Atlantic riparian wetland field study site. Soil core samples used to ground truth the procedures showed that the detection predictions were 92% accurate and tracer dye transmission through the site corroborated the morphology predictions. The results demonstrate the feasibility of using GPR to map preferential flow networks in situ without disturbing environmentally sensitive wetland ecosystems.

Ground-penetrating radar (GPR) is a nondestructive means of detecting buried objects with electromagnetic waves. It has been applied to detect coarse woody roots, estimate biomass, root diameter, and spatial distribution of roots. This chapter discusses the development of root assessment techniques, basic methodology, and examples of field applications where GPR was successful. IntroductionMany root quantification methods are destructive (e.g., soil cores, pit, whole-plant excavation) and prohibit repeated measurements over time. Destructive sampling yields high quality data, though it is expensive and labor intensive. Frequently, this leads to small sample sizes that may not adequately capture spatial variability and lack statistical power to reveal subtle treatment differences. For those who study

Using a semiquantitative question sheet, a radiologist estimated 36 radiographic properties upon each of 102 pathologically proven cases of benign and malignant disease of the breast. From these properties, a probability of malignancy was assigned to each case using an automatic clustering algorithm. The algorithm examined the properties of half the cases and evolved parameters with which to assign probabilities of malignancy to unseen cases. Then the validity of these parameters was tested using the other half of cases. Every mammogram used in this study had a pathologic diagnosis indicating that the surgeon was suspicious enough of malignant disease to operate. Using the properties and decision method described in the paper, the false‐positive rate was lowered 45% while keeping a false‐negative rate of zero in the same set of mammograms.