Work sampling and work process optimization in sonic and electrical resistance tree tomography

Abstract

Using non-destructive techniques in investigating tree stem rots is a modern approach in arboriculture and urban forestry. We used PiCUS^® 3 Sonic tomograph (SoT) and TreeTronic^® electrical resistance tomograph (ERT) to inspect the health status of urban and park trees. The process of setting up the device and measuring is time demanding as it requires numerous delicate operations. The aim of the study was to evaluate the time needed for measurement and to propose an optimal workflow. The results of work sampling suggest that scanning of one average-difficulty tree by SoT and ERT resistance tomography takes an average approximately 52 min (when one operator measures one scan), and approx. 37 min (when two operators measure a queue of trees). Working in two-person-team is moderately more efficient. Typically, the overall costs of one scan are approximately EUR 25–30 (~ CZK 650–780), depending on many variables.