Elementary school student Colin Innes discovered something sticky while digging a hole for a tree along Cleveland Avenue.

“Eew!” Innes said. “It’s gum.”

Innes and other fifth-graders from St. Paul’s Groveland Park Elementary School learned about trees Tuesday from the University’s Urban Forestry Club.

Dutch elm disease has killed elm trees in boulevards near the school, leaving behind stumps, club president Karl Mueller said.

Students got their hands dirty and planted a rare elm tree in the area, one that has proven resistant to Dutch elm disease, said Gary Johnson, University professor of urban forestry.

The children were interested in learning what killed the trees and finding out how long the tree they planted would be there. Teacher Jeff Sambs said it would last for at least 100 years.

Fifth-grader Autumn Austin said she did not like the beetles after learning that they harm elm trees.

“They should lay their eggs on a scorpion so (the scorpions) have something to eat,” she said.

Autumn said she likes trees.

“I like the way they look when it’s autumn, because that’s my name,” she said.

Trees have many benefits to urban areas, Mueller said. They provide oxygen and take carbon dioxide out of the air, he said.

Other benefits from trees include shade to make cooler cities, he said.

“Overall, it’s a really good resource that tends to be overlooked,” Mueller said. “People don’t realize how dynamic a resource it is. It can be used for so many different things.”

Johnson said the new disease-resistant tree is from Asia, which is where the beetle causing Dutch elm disease comes from.

In an effort to find a cure for Dutch elm disease, tree scientist George Ware went into the mountains of Asia, selected a tree and tested it for 30 years. Johnson said Ware had to make sure the tree would last in the United States. The tree planted today is a descendant of Ware’s tree.

Johnson said he expects the tree to look better as it continues to grow. The tree should survive cold weather and road salt from Cleveland Avenue, he said.

The club gave students a booklet to identify trees as they walked to Mississippi River to look at buckthorn, an invasive and exotic species of hedge.

Some groups and agencies are trying to remove buckthorn, he said. When animals eat it, he said, they cannot digest it, and it also crowds out native species.

Mueller said he was excited about talking to young children who can absorb information well.

The Urban Forestry Club has been around for less than five years, but the urban forestry major is nearly 10 years old, Mueller said.