As spring is unfolding here in Central Minnesota, so is the realization that thousands of ash trees are on the verge of dying. The emerald ash borer is now established in this region and will quickly kill all the ash trees which in this area are mostly of the green ash variety. That will effect the ecosystems here somewhat but the real threat to a Minnesota ecosystem is the black ash swamps in the northern part of the state. According to the Minnesota DNR:
Minnesota forests are home to an estimated 1 billion ash trees. Many of these trees are in nearly pure stands of black ash growing in wet areas, where they help maintain the water table. Once emerald ash borer has killed these trees, the wet forest habitat may change over to grass, cattails, and shrubs, threatening the plants and animals that rely on black ash and forest habitats.
This is why the DNR is trying to stop the transport of all firewood from the southern half of the state, which has borer infestations, to the north. The borer can only fly short distances so it relies on humans to transport it further. If you are interested in learning more on this, here is a good video from the DNR: Emerald Ash Borer and impacts to Minnesota forests
So what to plant to replace ash trees? The hackberry is one such native tree with significant benefits to wildlife. Its berry seeds ripen in September and persist on the trees all winter into spring. Many species of birds eat these berries including robins, bluebirds, cedar waxwings, flickers and game birds including turkeys and pheasants.
Hackberry trees are also host to many species of larvae and caterpillars that provide bird food during the migration and nesting seasons. When observing migrating warblers in my backyard, I notice that elms, oaks and hackberries are their preferred foraging trees during spring migration.
As for tree characteristics, the hackberry is a strong, moderately fast growing, somewhat shade tolerant species that can withstand heavy storms. It is not too picky about soil type but grows best in more moist, organic soils. Given space to grow, it will develop a mostly symmetrical, rounded crown which makes it a nice specimen tree. The only weakness is its lack of fall color but its ability to provide shade and be very durable makes up for the duller autumn color.
For those living in Hennepin County Minnesota, the County has a spring tree sale where you can order small saplings of Hackberry and other important native trees and shrubs. Here is the link: Hennepin County spring tree sale