Teaching Hands-on Urban Forestry Health Assessment Using the Resistograph and the CTLA Method

Abstract

Undergraduate students were instructed how to assess the health of 24 urban willow oak trees. Students received hands-on training using the Resistograph 400 on two sites: a depressional site and a well-drained site on the campus of Stephen F. Austin State University in an upper division Urban Forestry course. Students followed the instructed and prescribed method of drilling three holes at 120 degree intervals at 3.5 feet in height above ground in each oak tree. Tree condition data were recorded on paper strips and analyzed in laboratory for percent decay measured for each sample. The results were averaged for the three samples per tree and the percent of soundwood was determined. Resistograph data were then analyzed by the students using SAS ANOVA for the 24 trees within the two sites. Results indicted a significantly higher amount of decay on the depressional sites compared to the well-drained sites. Data collected using the standard CTLA tree health assessment method indicated willow oaks in depressional sites had a significantly lower condition rating based on six measured tree variables. This study demonstrated that incorporating intensive hands-on instruction within an undergraduate student’s education increases retention rates, enhances their educational experience, and produces a more well-rounded urban forester.