City tree nursery is testing ground for new varieties

Aberdeen’s tree nursery at Kuhnert Arboretum serves as a testing ground for new tree varieties and gives the Parks Department a place to plant smaller trees until they are mature enough to move to city property.

The tree nursery has been in use for the past 30 years, and city forester Aaron Kiesz said trees are planted and removed each year. This year, he said, about 200 trees will be added in the spring and 50 to 100 trees will be transplanted in the fall to city parks and along recreation trails.

From the time trees are planted in the nursery, Kiesz said, they grow from 7-foot-tall “whips” with a trunk width of about 1 inch to 5-year-old trees with a trunk width of 2 to 3 inches.

“The only risk in transplanting is if you don’t have a spade big enough to pull it out of the ground,” Kiesz said.

New varieties

All types of trees are planted at the nursery from shade and ornamental trees to evergreens, and Kiesz said, a few varieties proven to thrive in this area are probably lesser-known like the Ginkgo, Shagbark Hickory and Kentucky Coffeetree.

“We try a lot of different trees categorized as marginally hardy,” Kiesz said. “To show the public they can grow them.”

That’s the idea behind the arboretum – to be a place to experiment with different types of trees and see what works best in the northeastern South Dakota climate. When fully developed, the arboretum will be a place to showcase and test different tree varieties just like the rose garden is intended as a place where different rose varieties can be planted and tested to see how they acclimate to the region.

Kiesz said the Ginkgo has a proven history of growing well locally and can now be found on South Main Street and at Melgaard Park.

“We know it does well here,” he said. “It’s proven to work.”

The Ginkgo is a slower-growing shade tree, and features unique fan-like leaves, but it’s also a prehistoric tree with no known insect or disease problems, Kiesz said. That is an advantage considering recent tree disease issues with Dutch elm and pending pest issues concerning the emerald ash borer.

Another variety that’s been growing well for the past eight years is the Kentucky Coffeetree.

“There’s only a handful in town,” he said. “It’s very hardy, and another variety with little known insect or disease issues.”

The Shagbark Hickory has not been grown locally, but Kiesz said, it’s a new variety the nursery will be trying for the next three to five years to see how it grows.

“We think it will do well,” he said.

Survival rate

Not all trees survive, Kiesz said. About 10 percent die as a result of deer damage or because they simply don’t make it.

Even with the loss, Kiesz said, the nursery provides a savings to the city because the trees are about $50 when purchased and are worth about $300 by the time they’re transplanted.

The challenge, Kiesz said, is providing adequate water for the trees. The Kuhnert Arboretum, which is south of Melgaard Road on the east side of Moccasin Creek, currently has no irrigation system. That requires more time watering, weeding and tilling the area, Kiesz said.

“From here on out, we need to get donations for an irrigation system,” Kiesz said. “Irrigation is one thing we’re really lacking out there.”

Doug Johnson, director of the Parks, Recreation and Forestry Department, said he does not have an estimate on the cost to install an irrigation system.

The nursery is at the south end of the arboretum and covers less than five acres. Other activity at the arboretum includes some re-seeding and leveling of half the ground in preparation for a 3,000-foot recreation trail that will be built this summer.

“Once the recreation path is done, we can develop around the trail,” Kiesz said.

In all, he said, about 700 trees will be planted this year at the tree nursery and along boulevards and in parks, the city cemetery and at the golf course. Another 125 will be planted in front of new homes.

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