What kind of Maple is it?

One of the most recognizable trees in our landscape is the Maple tree. There are a number of common species in the plant genus Acer in Michigan. As a climbing arborist working in the trees, I can say that not all maples are equal.

There is a good chance that you may have one, or several maples on your property. Each species has characteristics that impact an arborist’s recommendations and management decisions. 

Below I will outline some generalizations on the common maple tree species I see in Michigan landscapes.

Probably the longest lived and sturdiest is the Sugar Maple, Acer saccharum. These tend to be slower growing in the urban landscape and they have the hardest and strongest wood, relatively speaking. There is also the Black Maple, Acer nigrum, which is very similar to sugar maple in leaf, form, habitat, etc. These trees are susceptible to a number of decay organisms such as ganoderma and armillaria while maintaining healthy appearances. They can get very large and lose significant portions of their canopies from storms. They should be inspected if they are within range of property like homes, cars, etc. That said, sugar and black maple is one of the most reliable, large shade trees we have.

Silver Maple, Acer saccharinum, is probably the largest growing within the group. But this often comes at a cost. They tend to grow fairly quickly and commonly break under their own weight. The architecture of these trees is frequently weaker, with included unions and arching, overextended limbs. It's like they just don’t know when to stop, and it turns into too much of a good thing! This species is quite commonly planted in front yards and can outgrow their space. Heavy pruning will almost always result in decay, which further destabilizes these trees. 

The Red Maple, Acer rubrum, is also fairly fast growing but very adaptable. In nature they tend to be a water loving tree but they often are planted in dry sites and perform admirably. This can lead to additional stress on the tree and it's not uncommon for them to outgrow small spaces and begin to dieback during dry years when their limited root zones become overtaxed. They also produce an abundance of poor unions that create branch bark inclusions. These later lead to branch failures when the attachment is no longer strong enough to support overly large leads. Early pruning of these trees can prevent this but is often missed. 

So far, all these trees are native, or endemic to our region. The Norway Maple, Acer Platanoides, is an introduced species. It grows quickly and disperses across the landscape with big crops of samaras (helicopter seeds that are typical of all maple species). They pop up all over in urban landscapes and can be problematic along fencerows, near foundations, and other narrow or small islands of available soil. They grow quickly and have somewhat brittle wood that makes them more susceptible to frost, wind, and snow breakages. If you have this tree close to your home, it's likely I would recommend heavy pruning, or removal of the tree before it becomes more of a problem. 

The Box Elder, Acer negundo, is a bit of a curveball in the maple genus since it has a compound leaf. It grows very quickly and also breaks easily due to its soft wood that is often attacked by decay fungus such as polypores. It can have very unusual, curvy forms that are interesting to look at, but I would recommend keeping this tree away from your valuables! These trees are very good at coppicing (new sprouts) and sending new growth from old wounds, stumps, etc. 

Japanese Maples, Acer palmatum, comprises one of the most popular and cultivated landscape trees in the world. There are hundreds of varieties but most stay relatively small. These can be very expensive to purchase and can benefit from routine care. Because many of them are raised in pots, they frequently develop stem girdling roots (SGR) that can cause early decline. Inspection of the trunk and roots is recommended before planting/purchase. These trees are sometimes impacted by severe winters here. Plant them in a location that is sheltered and consider winter protection for high-value specimens. 

There are a ton of other cultivated maple varieties that are commercially available in the plant trade. Many of them have been selected for quick growth and unusual leaf color (such as the Crimson King variety). Landscape plantings of these trees should take into careful consideration of their potential to get large and outgrow their space.

Frequent and early subordination pruning is vitally important for the entire Acer genus to avoid common problems like codominant stems and poor scaffold branch spacing. 

Avoid topping these trees as well because they all are poor compartmentalizers and will decay quickly while maintaining vigorous new shoots. Large pruning cuts (more than 4 inches in diameter) should also be avoided for the same reason.

Maple Decline is a problem that has recently been identified but without direct causation. It is a general term for any maple that may suddenly begin dying. Some symptoms include : scorching of leaves and dieback of branches, dead branches, years of subsequent dieback until the canopy is gone. Factors like drought and weather likely play a role, but climate change, verticillium wilt, and decay organisms are also under speculation. Some trees seem to recover, but for others one or two dead branches can quickly spiral into tree mortality. 

If you have a maple tree in your yard, take some time to further identify it and consult with a qualified arborist to further evaluate any risk or remediation options.