Minneapolis arborists scramble to plant 8,000 new trees

It's crunch time.

The Minneapolis Park Board's forestry department is scrambling to plant more than 8,000 new trees along boulevards and streets as part of the city's aggressive ash canopy replacement plan.

In a normal year, it's a mad dash of digging and planting, but April's record snowfall quickly followed by hot weather means trees not yet in the ground are sprouting.

"It's not a good combination," said Ralph Sievert, the Park Board's director of forestry. "That can really stress the trees."

About 60 crew members are working overtime all over the city, planting nearly 250 trees a day. They hope to finish the project by early June.

The race is on statewide to try to hold back the devastation caused by the metallic-green emerald ash borer. Its larvae feed on the tree's inner bark, disrupting its ability to transport water and nutrients. Eventually, the tree dies.

Minnesota has an estimated 2.65 million ash trees on public and private land and 1 billion in state forests, the highest number of ash trees of any state.

Last year in St. Paul, officials dedicated nearly half a million dollars to plant new trees and get rid of the ash tree stumps left behind when the budget came up short to do the work. When the ash borer infestation first appeared in the city in 2009, officials removed thousands more trees than expected and didn't have the money to plant new ones.

In Minneapolis, the removal of the trees is a concern but isn't the hot topic it was last year, said Dave Colling, executive director of the Harrison Neighborhood Association in north Minneapolis. "We've seen the new trees, but we are still not at where we were and where we want to be," he said. "...[T]here's still a lot of wait and see."

The thousands of trees come from as far away as Buffalo, N.Y., and as close by as the Hennepin County Adult Corrections Facility in Plymouth, which grows 50 species of trees. Trees are dormant during transportation and are shipped in large air-conditioned semitrailer trucks.

With summer quickly approaching, arborists are worried whether the trees can survive the shock of transplanting. Last year, planting started in the beginning of April. This year crews started in late April.

Ideally, the trees are planted during dormancy. When the weather changes and the trees are in the ground, their root systems can establish themselves before they leaf out, Sievert said.

Sievert says residents can help the trees adjust by watering them weekly.

"We find this to be amusing, but sometimes people tell us, 'Well, I didn't know I was allowed to water the trees,' " Sievert said. "It's almost impossible to overwater a tree."

Karen Zamora • 612-673-4647 Twitter: @KarenAnelZamora