Urban forestry researchers at the Southern University Ag Center have identified a solution to detecting internal tree decay by using state-of-the-art technology.

During a two-day workshop How to Detect Internal Decay of Trees, April 2-3, more than 50 urban forestry practitioners from Southern, LSU, and Grambling State University, extension agents from the Ag Center and USDA, urban forestry undergraduate and graduate students, and urban forestry professionals gathered at the Center to learn more.

The workshop focused on the application of the PiCUs Sonic Tomography Technology to detect internal decay of trees. The workshop participants learned not only the theory, but also gained hands-on experience in using the technology.

"Southern University is the only public institution in the US that currently acquired the Picus Sonic Tomography Instrument," said Qi, Professor of Urban Forestry, Southern University Ag Center Urban Forestry Program. "The technology will significantly enhance the capability of urban forestry research and extension at SU."

The technology works on live trees as well as wood. PiCUS® Sonic Tomograph is an instrument that measures the time and distance of the sonic waves traveling through the wood and calculates the velocity of the sound in the wood. The sonic waves travel quickly through solid wood, but slowly via damaged or decayed wood. The sound velocity is mapped out in different colors to show the locations of the solid wood and damaged wood.

The sound velocity correlates well with the wood density, thus representing the health conditions of the wood.

To demonstrate the technology, the workshop participants investigated a large water oak tree (Figure 1) located by the bluff on SUBR campus.

The test result showed the water oak tree has developed extensive internal decay at the base level which has extended significantly to the major portions of the trunk (Figures 2-4). The investigation also discovered the tree has a large internal cavity starting at the base level and extended decay on the major trunks within the canopy.

The sonic tomography provides visual 2-D and 3-D images (Figures 2-4) of internal conditions of the trees. It is an effective and powerful tool to assist landscape managers and urban forestry practitioners in hazardous tree assessment and urban forest management. "With acquisition of this technology, we will first provide assistance to the landscape department at Southern University to conduct a hazardous tree assessment on SU campus, to help maintain public safety with a healthier urban tree population on the campus. We also hope to provide the technological assistance to the city of Baton Rouge and the public in hazardous tree diagnosis and assessment" said Qi.

The two-day workshop was organized by Yadong Qi and Daniel Collins, Professors of Urban Forestry in partnership with Mr. Lothar Göcke, Argus Electronic GmbH, Rostock, Germany.


Click the picture for a larger view

Workshop participants investigate a water oak tree located by the bluff on SUBR campus using the ultrasound equipment.		This water oak, was measured at the base level, about 8 inches above the ground; the tomograph indicates the tree has decayed to the advanced stage. The outer dark and brown colors indicate the solid wood, about 18%; while the purple and blue colors indicate the damaged/decay wood, about 70%!

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