Mass Tree Die-Off #421972 - Ask Extension


Mass Tree Die-Off #421972

Asked August 18, 2017, 10:53 AM EDT

Why are a large number of trees around my house all dying nearly simultaneously? Nine trees, four in my front yard and five in my back yard, have died or appear to be dying, one last year and the rest all this summer. Three trees in the front yard were all conifers of the same species, while all of the other trees are deciduous trees of different species. Three of the trees in the back yard were fruit trees that were 33 years old, while all of the other trees were older, being mature when the property was purchased 33 years ago. I am not an expert on the subject, but this strikes me as being more than a little peculiar, particularly as all but two of the trees appeared to have been completely healthy, to my untrained eyes, as of last summer, and all of them had earlier been declared by a certified arborist to have been completely healthy, as of about five years ago. The grass and other ground cover in the vicinity of all of the trees appears to be healthy. I have never applied any pesticides, herbicides, fertilizers, chemicals or anything else to any of the trees or the soil on my residential property anytime in the last 33 years, with the exception of a some fertilizer for the lawn about 30 years ago. Not all of the trees on my property appear to be experiencing problems. Two cedars, directly adjacent to my house, at either side of the house in the front yard are fine, as is a shrub, or possibly more accurately, two shrubs growing together, in the front yard are fine. A mulberry tree and another deciduous tree, removed from the house, and on the property limits in my backyard are fine. Four "volunteer" deciduous trees immediately next to the house, three in the front yard and one in the back yard, that have been removed, also seemed to have been healthy.

Montgomery County Maryland

Expert Response

In order to really be helpful, we need to know the species of trees you have. However, we can make some general observations about trees dying, because a lot of trees--especially old trees--have been dying in Maryland.

We suspect the dying evergreens in the front yard are blue spruce, because all Colorado blue spruce die early in this region. They are not well-suited for the heat and humidity. It stresses them. Nevertheless they are popular and planted everywhere. Here is more about them:

Fruit trees are not long-lived trees. Thirty-forty years is a long life span for them.

In addition, many large old shade trees seem to be dying in this region. Stress from climate change, heat extremes and drought are suspected. Keep in mind that the larger the tree, the more water it needs.

We assume you have not done any construction or regrading of your property.
We would be glad to look at photos of individual trees, both to identify the species and to diagnose problems. Once a tree is dead, we cannot diagnose the cause of death. We need to see plants showing symptoms and see photos of the symptomatic parts, both overall and close-up photos.

There are several ways that popular landscaping contributes to problems--such as over-mulching or piling mulch on tree trunks. Take a look at this fact sheets for some lesser-known causes of tree problems:

Thank you very much for your quick response to my inquiry. I am afraid that I do not know the actual correct latin names of any of the plants on my property. The large, over 33 year old deciduous tree that I had removed from my front yard week or so ago, even though it still had a number of branches with leaves on them, was referred to by several arborists as a red maple. Two trees in my back yard with considerably more dead branches than live ones are a crab apple, over 33 years of age, and some type of pear tree, 33 years of age. The remaining fruit trees in my back yard all appear to be dead. All of the 4 fruit trees that are in my back yard, the older crab apple, and three others, all 33 years old, all stopped bearing any fruit towards the end of the previous decade. None of the (far fewer) trees on any of the three properties that adjoin mine have had any trees die, other than one smaller tree, that was a few feet from my property line in the front yard, that fell over during a storm. Might I impose on you a bit further for recommendations as to what long lived deciduous shade trees I should consider planting next spring, taking climactic conditions into consideration, to replace all the trees that I have lost? I am not interested in having any edible fruit bearing trees. The only consideration as to he size of the trees is that several smaller ones that I would like to place right next to the house should grow no taller than about 10 feet or so, otherwise, for others trees that I would intend to plant farther from the house, bigger would be largely better to my current way of thinking.
The Question Asker Replied August 18, 2017, 5:18 PM EDT
Almost no trees stay at 10 feet. Dogwoods (get a mildew resistant  variety), redbud, Japanese maple, crape myrtle, magnolias (many kinds), and dwarf crabapples are all considered small trees, but all get over that neight.  If the plant must stay small, consider a shrub, or at least a dwarf tree..  Some can be pruned with a single trunk.

Red maples are actually excellent shade trees. Oaks are famous for being long-lived. White oaks are especially disease resistant.  Sweet gums, black gums, other maples, other oaks, honey locusts, river birches are all possible shade trees.

Thank you very much for all of your help.
The Question Asker Replied August 21, 2017, 3:58 PM EDT

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