Tree of Heaven

Tree of Heaven

Ailanthus altissima
IMG_0600-scaled
Photo credit: E. Galloway

Status in Squamish:

ERADICATE

Status in Whistler:

PREVENTION-WATCHLIST

Status in Pemberton:

PREVENTION-WATCHLIST
Vectors of Spread:
Synonyms
  • Ailanthus glandulosa Desf.
  • Chinese sumac
  • Paradise tree
  • Stink tree
  • Stinking sumac
  • Varnish tree
ID Characteristics

General: Tree of Heaven is a small, fast-growing, deciduous tree.

Flowers: Small and white or pale yellow to light green. They grow in clusters that form a loose cone shape.

Stems:Young bark is light grey to brown; it becomes rougher as the tree matures. The tree grows to be 20 – 30 m tall and 10 – 15 m wide at maturity. The trunk can grow up to 1.8 m in diameter. New stems are yellowish to reddish brown and chunky.

Leaves: Compound and composed of oval leaflets with smooth edges, except for round or pointed lobes at the base of each leaflet. The compound leaves are large: 0.5 – 1 m long. When crushed, leaves emit a foul odour similar to burnt rubber.

Roots: Young trees have a taproot and large lateral roots, although the taproot may diminish over time. In rocky or compacted soil, this tree grows long, horizontal roots that do not branch until reaching more favourable soil.

Fruit: Showy, red, winged seeds, similar to samaras (maple’s ‘helicopters’).

Similar Species

Native

  • Smooth Sumac (Rhus glabra) is sometimes confused for Tree of Heaven. Smooth Sumac fruit resemble bright red berries, and Smooth Sumac turns red in the fall, whereas Tree of Heaven turns yellow.

Photo credit: Steven Katovich, Bugwood.org

Exotic (non-native)

Black Walnut (Juglans nigra), Japanese Walnut (Juglans ailantifolia) and Staghorn sumac (Rhus typhina) are all exotic trees with a similar leaf structure to Tree of Heaven.

  • Black Walnut (Juglans nigra) leaflets have toothed edges, unlike Tree of Heaven, which has smooth leaflet edges. Moreover, Black Walnut produces black nuts covered in a black husk, as opposed to Tree of Heaven, which produces maple-like samaras.

Rebekah D. Wallace, University of Georgia, Bugwood.org

  • Japanese Walnut (Juglans ailantifolia) produces nuts in bunches of 4 – 10, not samaras.

CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=152200

  • Staghorn Sumac (Rhus typhina) leaves are shorter than Tree of Heaven’s: 18 – 24 cm long, with 9 – 31 leaflets. Like other lookalikes, the Staghorn Sumac’s leaflet edges are serrated, unlike Tree of Heaven’s.

T. Davis Sydnor, The Ohio State University, Bugwood.org

Report

Please report any sighting of Tree of Heaven by clicking here.

Habitat and Origin

Tree of Heaven is originally native to China and Taiwan, but it is now found on every continent, with the exception of Antarctica.

Tree of Heaven prefers full to partial sunlight. Because it is tolerant of air pollution, compacted or poor soils and high winds, it has become widely established in urban areas, where it grows at roadsides, in parking lots, alleys, sidewalks, and other relatively inhospitable habitats. Tree of Heaven is intolerant of deep shade and flooding.

Current Distribution

Propagation & Vectors of Spread

Tree of Heaven reproduces by seed and vegetatively (by division). One tree can produce up to 325,000 seeds per year. While the seeds show fairly low viability, as well as low germination and establishment rates, the sheer amount of seeds produced ensures the plant’s reproduction.

Tree of Heaven also reproduces vegetatively, as it sprouts easily from cut stumps and root fragments.

Intentional planting (for ornamental purposes) is the primary vector of spread for Tree of Heaven. Seeds and roots can also be spread by vehicles and machinery; in addition, the seeds (samaras) can be spread in the wind 100 m or more, and can also be dispersed in water.

Ecological, Economic, & Health Impacts

Ecological: 

  • Crowds out other plants, reducing biodiversity.
  • Tree of Heaven is the preferred host for Spotted Lanternfly, an invasive insect that attacks fruit trees and vineyards.
  • Leaves are unpalatable to wildlife.
  • Decomposing leaves have allelopathic effects that inhibit the germination of native plants.

Economic:

  • The roots can damage infrastructure, like building foundations, and sidewalks.

Health:

  • Tree of Heaven pollen can cause allergic reactions.
  • Sap or plant parts can cause skin irritation.
What Can I Do?

Tree of Heaven is found in the Sea to Sky region, but with a limited distribution. The goal is to eradicate this species from the region, and to prevent new introductions.

Learn to identify Tree of Heaven: use the images presented in this profile page to learn how to identify Tree of Heaven.

What to do if you spot it: You can report any Tree of Heaven sighting by clicking here.

DO:

  • Regularly monitor properties for weed infestations.
  • Minimize soil disturbances and promptly revegetate disturbed areas to prevent the growth of Tree of Heaven.
  • Be PlantWise: choose non-invasive or native alternatives.
  • Ensure plants (particularly seed-bearing branches or root fragments) are bagged or covered to prevent spread during transport to designated disposal sites.

DO NOT:

  • Unload, park or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
  • Plant Tree of Heaven in a garden, no matter how well-contained its enclosure may seem.
  • Compost any plant parts, seed-bearing branches or root fragments. Instead, dispose of Tree of Heaven in the general/household waste stream at the landfill as the seeds will be able to persist the composting process.
  • Move soil, gravel, or fill that has been contaminated with Tree of Heaven.

Control

Mechanical 

  • Hand-pull small specimens; dig out bigger plants.
  • Cutting big plants or mowing seedlings may be effective, but must be done consistently (on a monthly cycle) to inhibit fruit and seed production.
  • Girdling (manually cutting away bark and trunk tissue) may also be effective, especially in spring when the trees are actively growing.

Chemical

  • Tree of Heaven requires persistent use of herbicide as its control is extremely challenging due to its ability to re-grow from stumps or root fragments.
  • Herbicide applications after cutting the tree is not recommended because it does not effectively control the roots.
  • Instead, apply herbicide to the tree during optimal times (July through September), wait around 30 days for symptoms to develop, then cut the tree down.
  • Triclopyr or glyphosate are recommended.

We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.

Biological

There are no biocontrol agents available for this plant.

References