To the untrained eye, it might look like arborist Craig Vollmer is administering a lie detector test to a tree.
One of the ways he assesses trees is by drilling a needle up to 18 inches into a tree trunk. A piece of paper will print out with squiggly lines that have peaks and valleys.
But instead of indicating whether or not the tree is lying, the tool, called a resistograph, tests how dense the tree is.
“As the needle penetrates the wood, it’s actually calibrated to measure the resistance it meets,” Vollmer said. “The denser the wood, the higher the resistance. If the wood is soft, it is because it is decaying; it will register that.”
Vollmer will demonstrate the use of a resistograph at a Bird, Tree & Garden Club Tree Talk at 1 p.m. Thursday, July 25 at the Burgeson Nature Classroom.
Vollmer currently works as regional manager and chief forester for FORECON, a natural resource and forestry consulting firm headquartered in Falconer, New York. He has worked as a forester and arborist for about 30 years, the last 13 at FORECON.
He received his associate degree in natural resource conservation from SUNY Morrisville, a bachelor’s degree in forest resource management and master’s degree in forestry from Syracuse University.
At FORECON, Vollmer assesses trees for private and municipal landowners.
“I look at the tree from top to bottom, evaluating the health and the condition of its crown,” he said. “I look for structural defects that might present problems for creating hazardous conditions, look at the roots and give an overall evaluation.”
The resistograph is just one tool Vollmer uses to evaluate the health of a tree, and it can detect whether a tree is decaying. Trees typically begin to decay when their bark is wounded.
“Usually it’s a wound of some kind where the bark has been taken off, or an insect has caused damage and allowed the wood to be exposed,” he said. “There’s all kinds of spores and fungi in the air. When they land on an open wound, they set up shop and start to break down the wood.”
Once he has determined that a tree has a problem with decay, Vollmer applies treatments including insecticides, fungicides and fertilization.
“I work hard to find every reason I can to keep a tree first, and remove it as a last resort,” he said.
From 2013 to 2015, Vollmer worked on an assessment of all of the trees on Chautauqua Institution-owned land — a total of about 4,000 trees at the time.
He assigned numbers to all the trees, mapped them and prioritized which trees should be dealt with first.
“We have certain trees that are flagged for an annual inspection because they have a structural defect,” he said. “We usually do inspection of these trees annually.”
Vollmer also updates the map he created to reflect where new trees have been planted, and old ones have been taken down.
Vollmer said he first got into forestry because he wanted to be able to spend his days outside; now he enjoys that continued opportunity and exploring tree and forest issues.
“Every tree has a story, and I like the challenge of figuring it out,” he said.