Tree of heaven (Ailanthus altissima) is a fast-growing deciduous tree. This species can be found in numerous habitats including old fields, forest edges, and urban areas where its used for landscaping. It can reach the height of 70 feet. The bark is gray to brown and has a texture that resembles a cantaloupe. The compound leaves are 1 to 3 feet long and are made up of 11 to 13 leaflets. There is a rounded tooth near the end of the leaflet. The female trees have small yellow/green flowers, and the seeds are winged and flat. Both the leaves and flowers smell like rotten peanut butter when crushed or ripped. One additional characteristic is heart shaped leaf scars.
Have you seen this species? Report it to us or on the MISIN website or smartphone app! Please include a photo to help with ID verification.
Environmental effects
Much like other invasive species, tree of heaven can form dense stands that crowd out native species in the understory. Tree of heaven also produces and secrets a chemical into the soil that is toxic to nearby plants. This further inhibits native plant growth. This species is also the host plant for the spotted lantern fly which is an invasive insect. Additionally, roots can damage man made structures and sewer systems. Mature female trees can produce 300,000 seeds annually. Mature trees can also send out root suckers as far as 50 feet.
Treatment
NON-CHEMICAL CONTROLS
- Hand pulling: this may be effective only with young saplings that are in moist soil. The entire root system needs to be removed to prevent resprouting
- All other mechanical methods are ineffective and could be harmful. Cutting and mowing tree of heaven without herbicide application could cause dozen of suckers to sprout from the root system.
CHEMICAL CONTROLS
- Foliar spraying: this method can be effective if the tree is small enough to completely spray the entire tree canopy. The best time to carry out this method is in mid to late summer.
- Basal bark application: this method can be used on trees less than 6 inches in diameter. The herbicide should be sprayed from the ground and then 12 to 18 inches up the tree trunk. Note: it is best to apply herbicide from mid to late summer.
- Hack-and-squirt: this method is effective for large trees. A downward cut is made into the trunk and then a concentrated herbicide is applied. It is best to apply the herbicide evenly around the tree but leave sections of uncut living tissue. This allows the herbicide to move into the tree roots. Note: it is best to apply herbicide mid to late summer.
Resources
State of Michigan’s Invasive Species Account: Tree of Heaven.