For a guy who’s been working with trees for some 18 years, could anything possibly surprise Joshua Kragthorpe as NRRI’s newest addition to the hybrid poplar team? Actually, yes.
“I was blown away by how many uses NRRI’s hybrid tree varieties have,” said Kragthorpe. “And I was surprised that we have our own named and patented tree, and by how they can be used for economic gain.”
The InnovaTree™ is the first of NRRI’s varieties to be commercially launched. This poplar is a cross between native Eastern cottonwood and European black poplar, naturally cross-bred over 25 years. It was cultivated to grow fast – up to 10 feet tall in just one year – with disease resistance in northern climates.
And it’s getting a lot of attention to address many challenges – polluted soils, carbon capture, quick shade – with six nurseries selling them across Minnesota.
Now Kragthorpe is tasked with keeping up with the demand. In his role as Silviculture Staff Technician, he works in the greenhouse propagating more poplar crosses for spring planting, preparing tree seedlings for research, and managing the poplar nurseries in Grand Rapids and Cohasset, Minn.
“I’m also identifying new silviculture research sites, installing vegetation measurement plots and collecting forest inventory data for silviculture projects across northern Minnesota,” he added.
But even though the InnovaTree is new to him, the work isn’t.
Joining the Team
Kragthorpe came to NRRI in March 2024 after 18 years working at the U.S. Forest Service Northern Research Station in Grand Rapids, Minn. And while the research world always intrigued him, he didn’t know where he’d end up.
He received his bachelor’s degree in biology at Bemidji State University in 2002 and was conferred a master’s degree in 2009.
“I thought about aquatic ecology first, but started working summers in forest research,” said Kragthorpe. “That opened up opportunities and ultimately I ended up doing silviculture research for the U.S. Forest Service.”
At NRRI, he is enjoying learning about the practical applications of InnovaTree, including their natural ability to uptake pollutants through their roots. This phytoremediation application has been tested by the U.S. Forest Service as part of the Great Lakes Restoration Initiative across 16 locations in the watersheds of Lake Superior and Lake Michigan. The InnovaTree is also being tested at a site in Aurora, Minn., near the St. James Pit Lake to use the trees to take up sulfate in groundwater.
NRRI’s program currently has over 500 hybrid poplar varieties archived in a nursery germplasm bank from 1,672 varieties and 115 families in 27 field tests at nine sites in Minnesota, as well as several trials in other states through cooperators.
Off Hours
When he’s not up to his knees in trees, Kragthorpe likes to do a little fishing. Perhaps that’s an understatement.
“My favorite activity is muskie fishing,” he said. “In the summer months, I’m a part-time muskie guide in the Grand Rapids area.”
Learn more about the InnovaTree: innovatree.umn.edu
PHOTO TOP: Josh Kragthorpe holds a 51.5 lb. muskie he caught in November on Lake Vermilion.