We feel like we are mourning the loss of an old friend. The stately old American elm tree in our front yard has succumbed to Dutch Elm Disease (DED). It has stood proudly looking over Victory Memorial Drive for nearly 100 hundred years and has shaded our house for as long as we have lived here and for many years before. Now it has lost at about 80 percent of its leaves and is sporting a bright orange ring around its trunk. It is a huge tree which survived the waves of DED in the ‘70s and ‘90s which leveled most of the American elms on the Parkway and on the boulevards across the city. We have been inoculating it every other year for at least the last 20 years, but I do think the heat and drought this summer contributed to the tree’s surrender to DED.
This past June was the second hottest June on record, and as of July 15, 80 percent of Minnesota was in at least a moderate drought. Needless to say our trees are stressed. We can help them out by watering. The question is when and how much. As we discussed last month, newly planted and young trees require a lot of water; generally 20 gallons a week in the first three to five years. In these drought conditions trees younger than three years require weekly watering and newly planted trees require daily watering. Older, mature trees have deeper roots so they generally don’t need watering if they get 1” or more of rainfall per week. But drought conditions are a different story.
If you have a mature tree, check the top soil near the base of the tree. If it is dry 9” below the surface then it needs watering. You can water the tree using an overhead sprinkler. Make sure the sprinkler spray reaches out beyond the canopy of the tree since the roots generally reach that far. Water in the early morning and on calm days so that the water is does not blow away or evaporate before it can soak in. Water deeply; shallow watering encourages shallow root development and the tree will be even more stressed when you stop watering and the top soil dries out. Other ways to help the trees is to remove weeds and other vegetation around the base of the tree which will compete for water, and mulch around the tree. This will reduce evaporation and help the soil to retain its moisture.
We are probably not the only people who have lost or will lose a tree these days. While there may not be too many elms left to succumb to DED, the latest tree scourge is the Emerald Ash Borer which is decimating our ash tree population across the city and the state. The Minneapolis Forestry Department is cutting down a quarter to a third of the ash trees on our boulevards and in the parks each year. They will replace these trees as they can. But if a diseased tree is on your property, it your responsibility to have the tree removed –and if you want a replacement tree, you also need to buy and plant one of your choosing. We will probably not replace our elm for a couple of years, giving the elm roots a little time to decay and the ground to settle. But we are already researching and discussing what type of tree we might like.
The first thing to consider is what type of tree would thrive in the type of soil we have. According to the University of Minnesota Forestry Department we live in the convergence of the Big Woods and the Anoka Sand plains. The soils in the Big Woods were formed by thick slabs of gray limey till left by glacial retreat. The Anoka Sand plains are flat sandy lake plains and terraces along the Mississippi with well-draining soil. The Big Woods was primarily a forested region populated with red oak, sugar maple, basswood and American elm, while the Anoka Sand plains originally showed oaks and some jack pines.
Many of the trees recommended by the U of M include the ones the City of Minneapolis is using to replace boulevard trees that they remove, including northern catalpa, Kentucky coffee, cork, gingko, linden and come maples. Most of the elms on Victory Memorial Drive were replaced with hackberries, because they are fast growing and have a similar vase shape as the American elm. Other trees recommended are paper or river birch, white or bur oak or a DED resistant elm, Valley Forge. The common eastern redbud has proven to be popular these days, but the U of M suggests it only as a tree to try. It shows promise but it does not have a long history in our area. If you choose to try one a tree from a northern seed source is recommended over others. For other recommended trees you can go to the U of M Extension website and search for tree selection and care.
So many trees to choose from and so little time for it to grow to grace and shade our house the way our stately elm did. But we don’t plant trees for ourselves; we plant them for the next generation.
-“Trees exhale for us so that we can inhale them to stay alive. Can we ever forget that? Let us love trees with every breath we take until we perish.” ― Munia Khan