How to identify and control invasive tree of heavens in forests

tree of heaven

When a landowner has a forest management plan in place, one of the common rules for making a forest stand healthier is to control invasive species. Some common invasive species found in forest stands are multiflora rose and non-native honeysuckle.

Another common invasion that I often find along field edges or fault areas is the Sky Tree. The scientific name for the sky tree is Ailanthus altissima. When speaking to rangers or other forest professionals, they use the name Ailanthus, or Sky Tree.

According to Penn State Extension, the sky tree was first introduced to the East Coast in the 17th century. It was popular for its extremely fast growth and ability to grow almost anywhere. Young sprouts can grow about 10 feet in a year if site conditions are good. This rapid growth and ability to adapt to most site conditions has resulted in the Tree of Heaven becoming a major tree pest.

The tree of heaven is also known to secrete a chemical into the soil that is toxic to surrounding plants, which can help reduce competition for resources and result in low plant diversity in a forest stand.

Where to find it

While the tree of heaven does not grow well in shady areas, it does take advantage of sunnier trails, paths, and other forest glades. It will take over these areas very quickly by cloning itself through root sprouting. These sprouts can be sent out up to 50 feet from the tree.

Skytree colonies include both “male” and “female” trees. The females produce up to 300,000 seeds each year. The seeds turn red in autumn and turn brown in winter. Female sky trees will often hold on to their seeds for much of the winter season.

How to recognize it

The sky tree resembles some native plants such as sumac and black walnut. To identify the tree, look for smooth leaf edges. The native trees have jagged edges.

Tree-of-Heaven also creates a bad odor when leaves or branches are crushed. Leaf scars on the sky tree are very large and branches have a brown, spongy center. The bark of the tree has vertical stripes and is smooth brownish green when the tree is young.

When the tree is older, the rind resembles the outside of a melon in color and texture. Older bark will still have those characteristic vertical stripes.


In addition to the sky tree’s negative effects on native tree populations, it can also have adverse effects on human health. Landowners should be careful when walking through or handling the Tree of Heaven. The tree produces a chemical in the sap that can cause swelling of the heart muscle if it enters the bloodstream through an open wound. The tree also produces a lot of pollen and is a source of allergy problems for some.

Unfortunately I found Tree of Heaven through many forest stands in Ohio. It’s especially easy to spot when driving on state highways.

If you find it

If a landowner finds this tree on their property, I urge you not to cut down the tree. Cutting down the tree will only cause the tree to send warning signals to the roots and lead to germination.

Please contact Ohio State University Extension for advice on chemical treatments. Penn State Extension also has great treatment tips on their website: If you think you may have a sky tree on your property but are unsure, contact your ODNR Division of Forestry Service Forester or the local SWCD office for identification assistance.

Spotted lanternfly is very fond of the sky tree as a host plant, so be sure to check each of these particular tree species for signs of the invasive insect.


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