Around 20 arborists and big-tree-enthusiasts met Friday morning in the historic Senate Chamber at the Old Capitol Museum for a seminar given by Mark Rouw, a longtime volunteer for the Iowa Department of Natural Resources’ Iowa Big Tree Program.
“It means a lot because most other groups are not as interested as these people,” Rouw said. “So I’m talking to an audience who, I know, gets it. It’s rewarding.”
During the first part of the seminar, Rouw gave a presentation on Iowa’s big trees. He covered several different ways to measure the heights and circumferences of trees to get accurate measurements.
Rouw also took attendees through decades of his own tree findings, sharing photos and measurements of state and national champion trees he’s monitored throughout Iowa. Rouw discussed his favorite Iowa Silver Maple trees, American Basswood trees, Black Ash trees, and more, all of which were of above-average height and width.
The University of Iowa’s campus is home to the state champion Black Walnut tree and Iowa’s second-largest American Elm tree, both of which have survived against all odds. The 130-year-old Black Walnut has a lightning-split trunk, but is in good health thanks to the installation of lightning rods in the tree, and currently stands at 95 feet tall.
The 19th century American Elm giant is one of two survivors of the Dutch Elm disease, which wiped out thousands of American Elms on campus in the ‘60s, according to the University of Iowa.
Today, the American Elm reaches a towering 93 feet. Both of these mammoth trees can be found on the Clinton Street side of the Pentacrest.
The event was hosted by Scott Carlson, the International Society of Arboriculture liaison for the Iowa Arborists Association.
“He’s the big tree guy,” Carlson said about Rouw. “He’s the guru here. So if you know of a big tree in Iowa, he already knows something about it.”
Rouw began measuring trees in the early ‘70s, before the Big Tree Program existed. He said the mission of the program is to bring awareness to the large trees around Iowa and help people become more concerned with preserving them.
During the seminar, Laurie Dams, the Iowa DNR’s Urban and Community Forest technician, said all trees in the Iowa Big Tree registry have now been assigned ID numbers to better track their growth.
The program is also working to include all the substantial trees across Iowa on its Big Tree Map.
“Some of these beautiful trees Mark showed you today are featured on our map,” Dams said to the arborists. “This is a way to take a nice big tree tour in the comfort of your own home.”
Following the presentation, Rouw led attendees around the Pentacrest to get a look at some notable big trees and practice tree measuring in the field, where the arborists employed the use of tangent lines and the “yardstick” method, where the measurer stands 100 meters away from the tree and holds up a yardstick to determine the proportionate height.
Rouw, who is also an animal specialist at the Science Center of Iowa in Des Moines, said his passion for trees began with identifying tree types and then expanded to hunting for the biggest trees he could find.
“I’ve always been interested in nature,” Rouw said. “I could have devoted my time to birds, or reptiles…but if I had to pick one thing, it would be trees. That’s what I’ve devoted the most time to.”