Remember the denuded streets that lay in the wake of Dutch Elm disease 30 years ago?

The city of Blaine remembers, and an aggressive new plan to remove all ash trees from city-owned land before they're hit by the emerald ash borer is meant to spread out the emotional pain of losing mature trees and the financial pain of replacing them.

"The clock's ticking; the sand's about out of that glass," said City Forester Mark Shippee. "Cities to the east found that once [the ash borer] is established, they're ashless within five years. And it's not tens or hundreds of trees dying; it's millions of trees dying. We can only assume that's what will happen here."

The city will start looking this week for distressed trees to be targeted for later removal.

In the years after Dutch Elm disease tore through elm-heavy communities, some of the older neighborhoods in southwestern Blaine were replanted, primarily with ash trees. The advantages of biodiversity -- i.e., that a variety of trees would leave an area less susceptible to being ravaged by a future disease -- didn't take hold right away.

"This was before the time cities probably had someone with an education in forestry," Shippee said. "Also, developers often do what's cheapest, and ash trees were probably a little less expensive tree to purchase than some others."

Many trees are 30 years old

While later developments were planted with a larger variety of trees, those old ash trees -- estimated to represent about 6 percent of the city's public trees, as many as 10,000 -- now are nearly 30 years old. They dominate some neighborhood landscapes, averaging 40 feet tall.

With the disease present in St. Paul and well-established in nearby states, Blaine plans to gradually remove all ash trees from city-owned land and residential boulevards over 10 to 15 years, if possible. The city would start with trees suffering obvious stress from leaf fungus, black gall and other problems that make them more susceptible to damage from ash borers.

The idea, Shippee said, is to avoid putting the entire cost of replacing thousands of trees on any one year's budget. And if the plan goes as hoped, residents shouldn't see a sudden large-scale change in the appearance of their neighborhoods.

If the city removes four trees on one block this year, then comes back to remove four more in a couple of years, by the time the last of the trees are removed, the first replacement trees will have had several years to acclimate and grow.

Shippee said he expects some of the new breeds to include hackberry, white oak, burr oak, linden, maple, beech, disease-resistant elms and ironwood, among others. The city will receive $71,200 from the state Department of Agriculture to help with its efforts. Shippee estimates the cost would be about $120,000 this year.

Shippee and Lynne Hagen, Anoka County's master gardener program coordinator, both said homeowners contemplating removing ash trees on their property should weigh the cost, financial and intrinsic, of losing healthy trees, many of which have some natural resistance and also can respond well to chemical treatments.

Policy could change

When the ash borer takes hold, though, Shippee warned, city policy could change quickly to avoid further spread and damage to property by diseased and dead trees.

Residents who are unsure of the species of the trees in their yard can contact the city forestry department for an at-home consultation, or take a sample to summer clinics offered by the Anoka County Extension office in Andover. And the city can help with the cost of replacement trees, with wholesale-priced trees available through its annual Arbor Day tree sale. Dates for this year's sale have not yet been set, but it's usually in early May, with pre-orders starting soon. Residents should watch the city's website and newsletter for updates.

Maria Elena Baca • 612-673-4409