Tree of Heaven

Tree of Heaven (Ailanthus altissima) was introduced in the late 1700s.  It crowds out native species; damages pavement and building foundations in urban areas (from USDA Plant Species Profiles).

Resources

LHPRISM (Lower Hudson Partnership for Regional Invasive Species Management) details the biology, impacts, and management of the invasive Tree of Heaven (Ailanthus altissima).

Key Identification Features

• Appearance: Deciduous tree growing up to 80 feet with thin, gray bark resembling a cantaloupe rind. It has large compound leaves with 10–40 leaflets.
• Odor: Leaves and stems emit a strong, unpleasant smell akin to rancid peanut butter when crushed.
• Seeds: Produces dense, drooping clusters of winged seeds (samaras).

Ecology and Impacts

• Habitat: Thrives in full sun or shade and highly disturbed human environments like roadsides and parking lots.
• Reproduction: A single tree can produce over one million seeds. While short-lived (under 100 years) with short-lived seeds, it reproduces aggressively through vegetative root sprouting.
• Ecological Threat: Outcompetes native plants and releases toxic chemicals (allelopathy) to inhibit nearby plant growth.

Management and Control

• Mechanical: Hand-pulling works only for small seedlings where the entire root is removed. Mowing, tilling, or girdling are not advised because cutting triggers aggressive root sprouting and creates brittle, hazardous dead wood.
• Chemical: Best managed with herbicides like glyphosate or triclopyr via foliar spray, cut-stump, basal bark, or stem injection methods.
• Best Practices: Successful eradication requires a combination of mechanical and chemical means, followed by mandatory monitoring for at least a year to address any re-sprouts or emerging seedlings.

If you are dealing with a Tree of Heaven infestation, let me know:

• The approximate size or age of the trees (seedlings vs. mature trees)
• The size of the infestation area (a few yard trees vs. a large property)

The USDA Forest Service Fire Effects Information System (FEIS) review of Ailanthus altissima (tree-of-heaven) provides a comprehensive analysis of this highly invasive species. The document highlights its rapid growth, prolific seed production, and ability to form dense clonal stands through root sprouting, requiring targeted herbicide management for effective control. The provided webpage is the USDA Forest Service Fire Effects Information System (FEIS) species review for Ailanthus altissima (tree-of-heaven), authored by Janet L. Fryer in 2010. It provides an exhaustive, literature-backed overview of the tree's botanical traits, fire ecology, and management impacts.

1. Introduction and Distribution

• Origin and Spread: Native to Taiwan and central China. It was introduced to North America via three distinct pathways—Pennsylvania (1784) and New York (1820) as an ornamental, and California (mid-1800s) during the Gold Rush for cultural and medicinal uses.
• Current Status: It has established globally in temperate climates. In the U.S., it is most invasive in the Northeast, the mid-Atlantic, and California, heavily occupying disturbed urban spaces and invading wildland riparian or logged zones.

2. Botanical and Ecological Characteristics

• Growth and Lifespan: A deciduous tree capable of reaching 60–70 feet tall. Individual stems are short-lived (30–70 years), but clonal expansion through extensive root sprouting allows a single individual to persist for centuries.
• Reproduction: It reproduces via aggressive root/stump sprouting and highly efficient wind-dispersed winged seeds. Individual mature female trees can produce over a million seeds annually, though they do not form a persistent soil seed bank (seeds survive less than a year in soil).
• Environmental Tolerance: Extremely drought-tolerant due to large water-storing lateral roots. Highly resilient to soil compaction, salinity, extreme low pH (down to 4.1), and severe industrial air pollution.

3. Fire Effects and Post-Fire Ecology

• Immediate Effects: Fire easily top-kills tree-of-heaven due to its thin, smooth bark.
• Response to Fire: Fire is not recommended for control. Top-kill triggers prolific, rapid root sprouting from its nutrient-rich root system, allowing it to quickly outcompete native species. Additionally, it readily colonizes freshly burned sites via off-site wind-dispersed seeds, with studies showing exponential population increases following thinnings or prescribed burns.

4. Ecological and Socioeconomic Impacts

• Ecosystem Alteration: Exhibits strong allelopathic properties. Toxic chemical extracts from its roots, leaves, and litter actively inhibit the germination and growth of neighboring native plants. It also alters nutrient cycling by increasing total soil nitrogen and calcium levels.
• Socioeconomic Damage: In urban environments, its aggressive, water-seeking root systems structurally damage foundations, concrete sidewalks, archeological remains, and sewer lines.
• Human Health Risks: Exposure to the tree's sap can cause severe contact dermatitis. Prolonged exposure of broken skin to the sap can lead to systemic issues, including elevated heart rates, chest pains, and myocarditis requiring hospitalization.

5. Control and Management Considerations

• Mechanical: Hand-pulling works for young seedlings if the entire root is removed. Simply cutting or girdling mature trees without chemical application is counterproductive, as it aggressively stimulates root suckering.
• Chemical: Systemic herbicides that target and kill the root network (e.g., triclopyr and glyphosate) provide the highest efficacy. However, land managers must exercise caution: tree-of-heaven roots can leak herbicides into the surrounding soil, unintentionally killing neighboring native trees via root grafts or shared mycorrhizal networks.
• Integrated Strategy: The most successful long-term management combines initial cutting paired immediately with local herbicide applications (like cut-stump or hack-and-squirt), alongside continuous monitoring for at least a full year to eradicate new sprouts.

If you are analyzing this document for specific management actions, please share:

• If you need a breakdown of the specialized herbicide methods (like basal bark vs. stem injection)
• If you want to explore the specific plant communities and regions most at risk in the U.S.

The USDA National Invasive Species Information Center (NISIC) serves as a centralized hub for tracking, mapping, and researching the invasive Tree-of-Heaven (Ailanthus altissima).

Key Documented Impacts

• Ecological and Urban Threat: The profile confirms that the species aggressively crowds out native vegetation and causes structural damage to building foundations and pavement in urban settings.

Breakthrough Biological Control Research

The page highlights significant investments and breakthroughs in developing organic, biological solutions to suppress infestations:

• The Spotted Lanternfly and Fungus Synergy (2024): Researchers at Virginia Tech received a $900,000 USDA grant to study whether the invasive spotted lanternfly can be leveraged to naturally transmit a lethal, tree-of-heaven-killing fungus from tree to tree, reducing human labor in eradication.
• Native Soil-Borne Fungus (2023): The USDA Forest Service Northern Research Station identified a native soil-borne fungus, Verticillium nonalfalfae, as a highly promising natural biological control mechanism capable of systematically reducing Ailanthus populations.
• Eriophyid Mite Discovery (2021): USDA Agricultural Research Service scientists discovered and verified the presence of a newly described Eriophyid mite in France. This mite is being evaluated as an option to control infestations across Europe and the United States.

Global and Regional Resource Repository

The website compiles official state, federal, and academic resource links to aid landowners and land managers:

• Mapping Resources: Connects users to the Early Detection & Distribution Mapping System (EDDMapS) via the University of Georgia to access GIS, state, and county distribution data.
• State Control Frameworks: Features localized landowner and management guides from state agencies across the country, including Virginia, New Hampshire, North Carolina, Washington, Missouri, Pennsylvania, Ohio, and Wisconsin.
• Academic Studies: Links out to dedicated extension fact sheets from Purdue University, the University of California, and Penn State.

If you would like to explore these biological control avenues further, let me know:

• If you want a deeper look into the Verticillium wilt fungus and how it spreads
• If you would like to find native plant alternatives recommended by these state resources to replace an eradicated Tree-of-Heaven

Other Resources:

Penn State Extension: Tree-of-Heaven (Ailanthus altissima) provides an operational field guide for identifying and managing the invasive Tree-of-Heaven (Ailanthus altissima) in Pennsylvania. It stresses strict operational timing and specific herbicide recipes to avoid triggering massive sprout responses.

Key Visual Identification and Look-alikes

• Bark and Twigs: The bark shifts from smooth brownish-green when young to light brown or gray, mimicking a cantaloupe rind. Twigs are stout, lack a terminal bud, have heart-shaped leaf scars, and break easily to reveal a brown, spongy center (pith).
• Compound Leaves: Leaves stretch 1–4 feet long and hold 10–40 leaflets. Leaflets have completely smooth edges except for 1–2 raised bumps (glandular teeth) at the absolute base.
• Native Look-alikes: It is commonly confused with native species like staghorn sumac, black walnut, and hickory. However, all these native trees have serrated (toothed) leaflet edges, whereas Tree-of-Heaven leaflet edges are completely smooth.

Crucial Management and Treatment Rules

• The Treatment Window: Systemic herbicides must only be applied in mid- to late summer (July until the onset of fall color). Applying chemicals outside this window merely causes "top kill" (damaging branches) without killing the root network.
• Cutting Safety Protocol: Mechanical cutting or mowing alone is entirely ineffective and triggers severe root suckering. If an unsafe tree must be cut down, land managers must apply systemic herbicide first, wait 30 days for symptoms to fully manifest in the roots, and then proceed to drop the tree.
• The Cut-Stump Ban: Traditional cut-stump chemical applications are explicitly not recommended for general control because they fail to stop root suckering up to 50 feet away.

Invasive Plant Atlas of New England website has images, similar species, management options and additional links for the Tree of Heaven, that are all related to New England and the northeast.

Invasive.org hosted fact sheet includes habitat, distribution, environmental impact, control and management, and references on Tree of Heaven.

Last updated August 21, 2026