Portland, Oregon is famous for the rich colors it takes on every autumn when the foliage turns beautiful shades of red, orange, and gold. Red alders, hemlock trees, douglas fir and a wide variety of other species all contribute to Oregon’s natural beauty. Other trees are not native, having been brought from places such as Europe and Japan, but are still just as lovely and contribute just as much to the beauty of the urban area. And while trees provide a multitude of benefits for residents, there are certain trees that are considered invasive or ‘nuisance trees’ and are not permitted by city ordinances in Portland. Maple trees are an example of this.
Maple, of course, is actually a very broad term, referring to an entire genus of trees, not all of which are on Oregon’s nuisance tree list. Sycamore maples, Japanese maples, and Norway maples are just a few of the tree species that fall under the umbrella category of maple trees. They are deciduous trees that can grow anywhere from 33 to 148 feet in height. They have a distinctive shape to their leaves and are known for the colors that they display during the autumn months. They can be very tolerant to shade and they grow flowers and fruit, which are considered very beautiful as well. Maple trees have a number of uses, including firewood and of course maple syrup, which is made from the sap. Maples can form canopies over roads and provide shade during summer, another reason they have become extremely popular over the years. The distinctive leaf of the maple tree sits prominently on the Canadian national flag. They are extremely popular all over the world as ornamental trees, being favored for planting on many commercial and urban, as well as residential properties.
So why aren’t they permitted?
With as popular as maple trees are, you may be wondering why they are considered a nuisance in Portland and so many other parts of the country. It isn’t all species of maple, however, that are invasive and therefore not permitted. The tree that has the largest reputation as a pest species is the Norway Maple (acer platanoides).
The Norway Maple
As their name implies, Norway maple trees are originally indigenous to the Scandinavian area, although they are found all across Europe. Over there, they are still a popular tree and their wood, which is of medium hardness, is used to construct musical instruments. Part of their popularity stems from the fact that they are easily transplanted from one area to another. They thrive in many different lighting conditions and also in many soil conditions, making them relatively easy to grow as far as trees are concerned.
In North America, however, they are considered a pest species and are banned in many municipalities, including Portland. Their bad reputation comes from the fact that their roots grow very close to the ground; because of this, they collect moisture before it can reach the roots of other plants. That means that when Norway maples are near, other plants and trees are often killed off by their growth. Even the grass that makes up urban lawns does not survive well when Norway maples are near. As a result, the tree may be attractive but it will leave the surrounding area barren and unappealing. It can also place native plants in danger as it degrades their habitat, leaching moisture away from them to sustain itself.
The Sycamore Maple
Another popular maple species is the sycamore maple (acer pseudoplatanus). This tree is native to Europe and Asia and is possibly the most common maple species. In Europe, the tree is still extremely popular and is used for making everything from firewood to a delicious honey made by local bees. In the areas it is native to, however, it is well adapted to the local environment and the nearby ecology has adapted to it as well. Other plants, as well as animals and insects, live in harmony with the Sycamore maple as long as it is in its natural environment. In areas it has been introduced to, however, it has a tendency to choke out other plant life due to its adaptability and fast growth. Because of this, the Sycamore maple is also considered a pest species in Portland and many other parts of the United States. It is not permitted to be planted and in some places, you do not need a permit to remove a sycamore maple tree.
Despite the problems they cause, these trees are renowned for their beauty and adaptability. If you are looking to achieve the benefits of having maple trees in your area without the problems that go with them, you should look for alternative trees which are native to the United States. The red maple (acer rubrum) and the sugar maple (acer saccharum) are native to the East Coast and make for a slightly better choice for planting in this country, although they also have shallow roots that may interfere with the growth of grass.
In the Portland area, however, maples are already extremely common; that’s why finding alternative species is your best option. Consider planting trees that are native to the Portland area instead of maples. Trees like the White Oak or the Wild Lilac will provide all of the beauty that maples do without harming the delicate natural ecology.
As we have mentioned, you often do not need a permit to remove a maple tree in your area, depending on the local ordinances. Even so, make sure you call your Urban Forestry department before taking any steps to remove a tree. Once you have done so, contact a reliable tree service such as Mr. Tree, which can remove invasive species like maple trees and replace them with more ecologically sound choices. A professional tree service can also help you maintain your local trees, pruning them and helping to keep them free of diseases and parasites.