Tree of heaven - CKISS - Central Kootenay Invasive Species Society

Ailanthus altissima

Description

Deciduous tree that grows up to 30 m tall
Bark is smooth and brownish-green (young), becoming rougher and brown-grey (mature), resembling the skin of a cantaloupe
Twigs are smooth, greenish/pink/reddish/brown, and have heart-shaped leaf scars when broken
Leaves up to 50 cm long, are green (summer) vs. yellow (fall), contain multiple leaflets, and have smooth margins except for two lobes at the base. The lobes have a gland on the underside.
Nicknamed “stinking sumac” because the leaves release a foul odor when crushed
Flowers are small, white-greenish, and grow in clusters
Produces red-brown clusters of pod-like samaras containing one seed each

Mature tree of heaven patch.

Young, greenish stem/trunk of tree of heaven.

Older, brown stem of tree of heaven with rougher, cantaloupe-like texture.

Tree of heaven whorl of leaves.

Tree of heaven heart-shaped leaf scar on stem.

Tree of heaven leaflets.

Tree of heaven leaflets, front and back.

Pair of toothed glands at base of leaflets.

Tree of heaven flower clusters.

Tree of heaven seed pods (samaras). Note the one seed per pod.

Tree of heaven young sapling.

Native to China and Taiwan
Introduced to North America for ornamental purposes
Believed to have the most rapid growth of any tree (native/non-native) in North America
Resistant to drought and tolerates various conditions, including nutrient poor soils and pollution
Resistant to predation from herbivores and pathogenic diseases
Reproduces by seed and vegetatively
Can produce 300,000+ seeds per year and has a high germination rate

It is the preferred host of spotted lanternfly (Lycorma delicatula), an invasive insect that severely threatens the agricultural (particularly fruit) and forestry industries
Displaces native vegetation by outcompeting plants for resources and releasing toxic chemicals into the soil
Thrives in full sunlight, impacting early-successional plant communities
Reduces forage for wildlife
Impacts infrastructure: its roots can penetrate asphalt, walls, building foundations, and it can enter sewers
Impacts human health: pollen can cause allergic reactions, sap can cause dermatitis, and it may (very rarely) cause myocarditis if it enters the bloodstream
Costly and difficult to eradicate

Tree of heaven is classified as Eradicate on the CKISS Annual Priority List.

Tree of heaven occurs in the CKISS region at a very limited distribution, so eradication is the management goal.
It has not been detected in the Kaslo or Nakusp Invasive Plant Management Areas, where it is classified as Prevent.
Please report sightings of this species immediately.
To learn more about how CKISS classifies and manages invasive species, see our Invasive Species Priority Lists page.

Prevention

Do not plant this species. Learn about Grow Me Instead and PlantWise to grow non-invasive alternatives.
Do not move contaminated soils to a new area.
Clean clothing, boots, and gear before entering/leaving an area.
Monitor tree of heaven for spotted lanternfly and report sightings to CKISS and EDDMaps.

Mechanical control

Digging/Hand-pulling seedlings can be effective if the entire root system is removed.
Simply cutting the tree down is ineffective because the tree will re-sprout.
Ideally, treat with herbicide and wait 30 days for the tree to die before cutting it down.
Consider seeking a professional to remove tree of heaven from your property.

Chemical control

Requires persistent treatments because it can re-sprout from stumps and root fragments.
Applying herbicide to a cut stump will not prevent new growth from the roots.
Requires ongoing monitoring for regrowth and repeated applications.
Herbicides with triclopyr or glyphosate can be effective control and can minimize effects on non-target plants.