From the tops of Twin Cities area trees, forestry crews see clear signs of trouble

The Twin Cities tree tops have changed since Sydney Hudzinski began climbing into them five years ago.

More twigs are dying. Some leaves change colors early. Many show signs of emerald ash borer damage. Mature, sensitive trees are especially stressed, while others still seem to be thriving.

“It’s been an interesting year,” said Hudzinski, a Plymouth forestry technician who spends her workdays climbing to the tops of city trees to evaluate their condition and prune them.

It’s been an especially busy year for forestry teams throughout the Twin Cities metro area. Severe storms followed years of drought, just as the emerald ash borer damage is approaching a predicted peak. Some trees fell down. Others were removed. Leafy neighborhoods are little more sparse.

“The Twin Cities is gonna suffer, is suffering, will suffer more from a community perspective than the rest of the state, just because there is just such a huge density of community ash trees through that urban area,” said Mark Abrahamson, plant protection division director for the Minnesota Department of Agriculture.

The emerald ash borer is an invasive beetle that burrows into trees, depositing larvae that eventually starve the tree by severing the channels it uses to take in water and nutrients. It’s always fatal.

Borer damage “really exploded” in St. Louis Park between 2022 and 2023, said Michael Bahe, the city’s natural resources manager.

Crews sprayed paint onto dying trees, marking them for removal. Old trees that provided lots of shade have been replaced by newer ones that will take years to grow to full size.

This year also brought four storms with severe wind, one of which was thought to be among the most damaging storms of the past decade. City leaders said crews worked hundreds of hours of overtime as they responded to a deluge of calls reporting trees or limbs that had fallen down and blocked roads.

Ultimately, the damage affected just a small percentage of the public trees. But “any loss of canopy hurts right now with our issues with emerald ash borer and then the drought,” Bahe said.

Crews in Minnetonka, which has one of the densest tree canopies in the metro area, have also had an “out of the ordinary year,” said city forester Hannibal Hayes.

“We’re struggling to keep up with the response to the storms, and so are tree care companies, too,” Hayes said.

Local leaders expect to spend more money this year contracting with companies to remove trees, even though the mild winter left city workers with more time to do some removals themselves. In total, the city expects to spend nearly $500,000 responding to storm damage, drought and the emerald ash borer.

The losses have left cities trying to grapple with another puzzle: what to do with all the wood that is left over. Piles of wood waste from metro area trees are growing. Minnetonka has been selling logs to professionals who supply furniture companies and other businesses. The city also purchased a portable sawmill that staff can use to create lumber for their projects.

The emerald ash borer was first recorded in Minnetonka in 2019, and Hayes suspects they’re at “the very beginning of the high-water mark for the death curve.”

Like their peers in other cities, Minnetonka foresters are trying to increase the diversity of their tree canopy. New plantings aim to ensure that, with few exceptions, no individual species accounts for more than 5% of the tree canopy.

Plymouth City Forester Paul Buck has also had to make budget adjustments as his team handles removals and gives preventative treatment to ash trees that aren’t yet showing signs of infections. They always expect to do some removals and maintenance, but this year has been especially busy.

“The forests turn over anyway,” Buck said. “They just don’t turn over this fast usually.”

When the removals eventually taper off, Buck hopes they’ll be able to use more of the budget to boost efforts to plant replacement trees.

In the meantime, Hudzinski, who competes in international climbing competitions, continues to ascend the trees to search for signs they need care.

She looks a little more closely at the ash trees and avoids scaling ones where half the leaves are missing. She looks for thick branches that seem steady and avoids thinner ones that are more likely to fail.

She sees clear signs that more trees are declining. But she also sees others that remain strong.

For the most part, she said, the trees are “still doing their thing.”