TERMITE GALLERY CHARACTERIZATION in LIVING TREES USING DIGITAL RESISTOGRAPH TECHNOLOGY

Abstract:
Characterization of populations of subterranean termites on a research facility in New Orleans, La., determined that a number of living trees were infested with the Formosan subterranean termite, Coptotermes formosanus Shiraki. The amount of internal tree damage was evaluated using a resistograph. The resistograph is functionally a cordless “smart” drill that transmits information to a computer regarding the mechanical properties of wood along the length of the drill hole. A rapid fall in drilling energy at a certain depth indicates the presence of a gallery. Plots of these data quantify the presence of termite galleries through detection of changes in tree density. Probing of a tree on different sides was critical for detection of termite galleries, which were generally not centrally located. Termite galleries were detected in 58.3% of the 12 infested trees as follows: 3 of 5, 2 of 4, and 2 of 3, bald cypress, live oak, and pine trees, respectively. Of the termite-infested trees, 33.0% were deemed likely to fail, specifically, 2 cypress and 2 pines. The resistograph is a viable tool for locating and quantifying internal structural loss of trees and causes minimal damage to the tree. Acquired information can be incorporated into a decision-making process regarding the structural integrity, safety, and the suitability of a tree for removal or drill and foam treatment.