California Invasive Plant Council

Ailanthus altissima

Synonyms: A. glandulosa Desf.

Common names: tree-of-heaven; Chinese sumac; paradise-tree; copal-tree

Ailanthus altissima (tree-of-heaven) is a deciduous tree (family Simaroubaceae) that is widely, but somewhat discontinuously distributed in California. It is native to parts of China and Taiwan and first introduced as a landscape ornamental to Europe and the United States in the 1700’s. Since then, it has escaped gardens, established in the wild, and spread widely through seeds and creeping roots that produce many suckers. In California, it is most abundant along the coast and mountain foothills, primarily in wastelands and disturbed, semi-natural habitats. Tree-of-heaven is considered invasive because of its ability to establish, spread quickly and dominate landscapes, as well as its allelopathic properties, which help to suppress surrounding vegetation. It can be distinguished by its large, pinnately compound leaves with often asymmetrical lanceolate leaflets. Leaves can smell like rancid peanut butter when crushed (unlike similar-looking walnut trees). Stems will show large heart-shaped leaf scars. Fruits are samaras. More recently, concern about tree-of-heaven has increased because it is a preferred host for a destructive and invasive insect pest, the spotted lanternfly.

Cal-IPC Rating: Moderate?

Explanation of Cal-IPC ratings

• High – These species have severe ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal and establishment. Most are widely distributed ecologically.
• Moderate – These species have substantial and apparent-but generally not severe-ecological impacts on physical processes, plant and animal communities, and vegetation structure. Their reproductive biology and other attributes are conducive to moderate to high rates of dispersal, though establishment is generally dependent upon ecological disturbance. Ecological amplitude and distribution may range from limited to widespread.
• Limited – These species are invasive but their ecological impacts are minor on a statewide level or there was not enough information to justify a higher score. Their reproductive biology and other attributes result in low to moderate rates of invasiveness. Ecological amplitude and distribution are generally limited, but these species may be locally persistent and problematic.
• Alert – An Alert is listed on species with High or Moderate impacts that have limited distribution in California, but may have the potential to spread much further.
• Watch – These species have been assessed as posing a high risk of becoming invasive in the future in California.

CDFA Rating: C*?

Explanation of CDFA ratings

• A – A pest of known economic or environmental detriment and is either not known to be established in California or it is present in a limited distribution that allows for the possibility of eradication or successful containment.
• B – A pest of known economic or environmental detriment and, if present in California, it is of limited distribution.
• C – A pest of known economic or environmental detriment and, if present in California, it is usually widespread.
• D – An organism known to be of little or no economic or environmental detriment, to have an extremely low likelihood of weediness, or is known to be a parasite or predator.
• Q – An organism or disorder suspected to be of economic or environmental detriment, but whose status is uncertain because of incomplete identification or inadequate information.
• * – An asterisk next to the rating indicates that a plant is included in the CCR Section 4500 list of California State Noxious Weeds.
• -* – This plant is included in the CCR Section 4500 list of California State Noxious Weeds, but is otherwise not rated.

More details

Assessment(s)

Plant Assessment Form - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.

Species ID Card

Invasive Species ID Card - To support field identification of early detection species, Cal-IPC has designed a set of Species ID cards that can be downloaded, printed double-sided, and trimmed to size.

Weed Management Notes

• Management Notes - Information on management techniques and effectiveness from the University of California Cooperative Extension’s Weed Research & Information Center.

Cal-IPC Newsletter Articles

• A promising agent to control tree-of-heaven. Cal-IPC. Vol 29, Issue 2
• Are we making progress? A bird's-eye view of change in invasive plant cover in central-coastal Orange County. Burger, Jutta C.. Vol 27, Issue 2
• Spotted lanternfly, a new threat (and tree-of-heaven, an old one). Kelch, Dean. Vol 27, Issue 1
• Working on weeds in the eastern US. Meyer, Tanya. Vol 22, Issue 1
• Taking to the air to locate, prioritize and treat effectively. Burger, Jutta C.. Vol 21, Issue 2
• Fighting weeds with the best of them. Cal-IPC. Vol 15, Issue 1
• The basal bark method of applying triclopyr herbicide. Neill, Bill; Angeles, Team Arundo. Vol 13, Issue 1
• Drilling Ailanthus. Kitz, Jo. Vol 08, Issue 2
• Results of the CalEPPC questionnaire at Symposium ’98 in Ontario. DiTomaso, Joe. Vol 06, Issue 4
• Legendary stewardship award. Goode, Suzanne. Vol 06, Issue 2
• A working paper on Ailanthus. Kitz, Jo. Vol 05, Issue 3
• Ailanthus altissima (Miller) Swingle: Its biology and recent history. Hunter, John C.. Vol 03, Issue 4
• California Exotic Pest Plant Council draft list exotic plants of greatest concern October 1993. CalEPPC. Vol 01, Issue 4

Cal-IPC Symposium Presentations

Presentations are linked where available. Where a presentation is not available, find more information by reading the abstract in the Cal-IPC Symposia Archive.

• Developing a post-fire EDRR framework. Quon, Lauren; Fitch, Robert; Laskey, Hailey (2022)
• Tackling invasive plants after the 2020 Angeles National Forest fire season. Castro, Andrew (2022)
• Ailanthus altissima control methods. Neill, Bill (2021)
• California listed plants and ratings. Price, Robert (2021)
• The role of public gardens as sentinels of plant invasion. Culley, Theresa; Dreisilker, Kurt; Ryan, Clair; Landel, Hans; Cavallin, Nadia; Arcate Schuler, Jessica; Shultz, Brittany; Gettig, Roger; Havens, Kayri (2020)
• Adapting treatment methods for Ailanthus altissima adjacent to sensitive fish habitat. Wing, Rachel; Castro, Andrew; Fraga, Naomi; Sale, Billy; Snyder, Kristy; Soto, Alejandra (2019)
• Partnering with California Conservation Corps on large scale weed removal in the Oroville Wildlife Area. Ferrara, Holly (2019)
• Pacific Gas and Electric Company’s use of Safe Harbor agreements to enhance habitat for endangered species in the San Francisco Bay Area. Dedon, Mark F.; Fry, Michael E.; Beesley, Peter M (2010)
• Invasive plant control at California State Parks in the northern Sacramento Valley. Dempsey, Jim; Elliott, Woody (2005)
• Trees and shrubs discussion group. Heath, Mark; Moore, Ken; Unger, Petra (2005)
• The abundance and distribution of non-native woody species in Sacramento Valley riparian zones. Hunter, John C.; Sterling, John C.; Widdowson, William P.; Beedy, Edward C.; Stralberg, Diana; Nur, Nadav (2003)
• Trial of several herbicides and application techniques for control of Ailanthus altissima, Upper Putah Creek, Yolo County. DiTomaso, Joe; Kyser, Guy (2002)

Other Ailanthus altissima Information

• Bugwood - National database from the Center for Invasive Species and Ecosystem Health at the University of Georgia.
• CalPhotos - Images of plants taken mostly in California.
• Calflora - Distribution map and records of this species in California.
• CalWeedMapper - Distribution map of this species in California with ability to determine regional priorities.
• EDDMapS - Distribution of this species in North America.
• Jepson Interchange - Information on this plant's taxonomy, biology, and distribution from UC Berkeley's Jepson Herbarium.
• USDA PLANTS Database - Information on identification and distribution, with links to websites in individual states.

Additional photos