Tree of Heaven Fact SheetTree of Heaven
Ailanthus altissima (Mill.) Swingle
Quassia family (Simaroubaceae)
NATIVE RANGE
Central China
DESCRIPTION
Tree-of-heaven, also known ailanthus, Chinese sumac, and stinking shumac,
is a deciduous tree in the mostly tropical quassia family. Mature trees can
reach 80 feet in height. Ailanthus has smooth stems with pale gray bark and
twigs which are light chestnut brown, especially in the dormant season. Its
large compound leaves are 14 feet in length, alternate, and composed of 10-
41 smaller leaflets. Each leaflet has one or more glandular teeth along the
lower margin. The leaf margins are otherwise entire or lacking teeth.
Ailanthus is a dioecious ( "two houses ") plant meaning that male and female
flowers occur on separate plants. Flowers occur in large terminal clusters and
are small and pale yellow to greenish. Flat, twisted, winged fruits each
containing a single central seed are produced on female trees in late summer
to earty fall and may remain on the trees for long periods of time. The wood of
ailanthus is soft, weak, coarse - grained, and creamy white to light brown in
color. All parts of the tree, especially the leaves and flowers, have a nutty or
burned nut odor.
Lookalikes: it is important not to confuse native shrubs and trees with ailanthus. Native sumacs (Rhus) and trees like ash
(Froxinus), hickory (Carya), black walnut, butternut and pecan (Juglans) can be distinguished from tree-of-heaven by
having completely serrated (toothed) leaf margins.
ECOLOGICAL THREAT
Tree -of- heaven is a fast- growing tree and a prolific seeder, that can take over sites, replacing native plants and forming
dense thickets. Ailanthus also produces chemicals that prevent the establishment of other plant species nearby. Its root
system may be eaten" and has been known to cause damage to sewers and foundations.
DISTRIBUTION IN THE UNITED STATES
Tree-cif-heaven is occurs in many states across the continental U.S. and
Hawaii and to date has been reported to be invasive in natural areas in 30
states (see map).
HABITAT IN THE UNITED STATES
Tree -of- heaven is a common tree in disturbed urban areas, where it sprouts up
just about anywhere, including alleys, sidewalks, parking lots, and streets. For
example, the book "A Tree Grows in Brooklyn," by Betty Smith, is based on the
tree -of- heaven. Away from cities, ailanthus is commonly seen in fields, and
along roadsides, fencerows, woodland edges and forest openings. It occurs as seedlings that pop up by the hundreds in
recently planted fieMerid4a persistent thickets in rocky, untillable areas. Nationally, ailanthus is recognized to be a
serious agricultural
BACKGROUND
Tree-of-heaven was first introduced to America by a gardener in Philadelphia, PA, in 1784, and by 1840 was commonly
available from nurseries. The species was also brought into California mainly by the Chinese who came to California
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during the goldrush in the mid- 1800s. Today it is frequently found in
abandoned mining sites there. The history of ailanthus in China is as old as the
written language of the country.
BIOLOGY 6 SPREAD
Tree -0f - heaven reproduces both sexually (by seeds) and asexually through
vegetative sprouting. Flowering occurs late in the spring. Ailanthus is
dioectous, with male and female flowers on separate plants. The fruits, or
samaras, occur in terminal clusters on female plants during the summer, and
may persist on the tree through the winter. One study reports that an individual
tree can produce as many as 325,000 seeds per year. Established trees also
produce numerous suckers from the roots and resprout vigorously from cut
stumps and root fragments.
MANAGEMENT OPTIONS
Elimination of Ailanthus requires diligence, due to its abundant seed production, high seed germination rate, and
vegetative reproduction. Followup monitoring and treatment when needed should be an integral part of any serious
ailanthus management program. Regardless of method selected, treated areas should be rechecked one or more times a
year and any new suckers or seedlings treated (cut, sprayed or pulled) as soon as possible, especially before they are
able to rebuild root reserves. Establishing a thick cover of trees (non - invasive and preferably native) or grass sod will help
shade out and discourage establishment of ailanthus seedlings. Targeting large female trees for control will help reduce
spread of ailanthus by seed.
Biological
Several fungal pathogens are being investigated as potential biological controls for ailanthus. Two of these, Verticillium
dahlias and Fusarium oxysporum, have been isolated from dead and dying ailanthus trees in New York and in southern
and western Virginia. A disease affecting ailanthus in PA was studied using inoculations in the lab and on canopy field
trees, the agent was identified to be Verficillium albo -atrum and is being suggested as a potential biocontrol agent pending
further studies including risk analysis. None are available for use at this time however.
Manual
Young seedlings may be pulled or dug up, preferably when soil is moist. Care must be taken to remove the entire plant
including all roots and fragments, as these will almost certainly regrow. Root suckers appear
similar to seedlings, but would be connected to a preexisting lateral root, and would be nearly
impossible to remove effectively.
e is usually counter - productive because ailanthus responds by producing large
stump sprouts and root suckers. However, for small infestations, repealed cutting of
time can exhaust the plants reserves and may be successful it continued for many
are heavy shade exists. If possible, the initial cutting should be in early summer in
act the tree when its root reserves are lowest. Cutting large seed producing female
at least temporarily reduce spread by this method.
festive method of ailanthus control seems to be through the use of herbicides, which
lied as a foliar (to the leaves), basal bark, cut stump, or hack and squirt treatment.
d that it is relatively easy to kill the above ground portion of ailanthus trees, you need
ously damage the root system to prevent or limit stump sprouting and root suckering.
.xtremely careful with herbicide applications in the vicinity of valuable ornamental
trees.
Foliar sprays applied when trees are in full leaf are very effective, and should be the method of choice where ailanthus
size and distribution allow effective spray coverage of all foliage without unacceptable contact with nearby desirable
vegetation or applicator. Where ailanthus is in association with other exotic weed species, as is often the case, foliar spray
allows treatment of the entire area at one time. Limitations of the method are the seasonal time frame, the need to
transport a larger, more diluted volume of spray material, and the fact that rapid growing ailanthus are often out of
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effective reach. The non - selective herbicide glyphosate (e.g., Roundup®, Rodeo®, Accord®), will kill or injure almost any
plant, herbaceous or woody, contacted by the spray. Tdclopyr (e.g., Garlon® 3A, Garton® 4) is selective for broadleaf and
woody plants and will not kill grasses contacted by the spray. Both glyphosate and triclopyr are systemic herbicides,
meaning that they are absorbed by plants and are carried to the root systems. These herbicides have low, soil activity, so
do not pose a threat to groundwater if applied properly and at recommended label rates. Both glyphosate and triclopyr
should be mixed with water and a small amount (0.5 %, or as per label) of a non -ionic surfactant (except for Roundup(D,
which contains a surfactant) to help the spray spread over and penetrate the leaves. The mixture should be applied to
leaves and green stems, including sprouts and suckers, until thoroughly wet but not to the point of runoff. With backpack
sprayers, concentrations of 2% of a typical glyphosate product such as Roundup8l or Accord® applied June 15 -
September 15, or 1.5% of a 4lb. /gallon triclopyr product such as Garlon® 4, or 2% of a 3lb. /gallon triclopyr product such
as Gadon® 3A applied June 1September 1 have worked well in the Mid - Atlantic area, with slightly greater effectiveness
for the triclopyr products. For higher volume applications such as would be applied by a truck mounted sprayer, the
concentration for these products could be reduced by 0.5% to 1 -1.5 %. Other herbicides which have shown to be effective
for foliar application of ailanthus are imazapyr (e.g., Arsenal®, Chopper®), and metsuffuron methyl (e.g., Escort®).
Basal bark application is one of the easiest methods and does not require any cutting. It works best during late
winter /early spring and in summer. The base of the tree stem must be free of snow, ice, or water on the bark from recent
rainfall, though precipitation following application is inconsequential. Late winter /early spring (February 15 -April 15, Mid -
Atlantic) is generally the most productive time, since vegetation near the base of the trees is usually absent or leafless.
Late spring and early summer applications (April 15 -June 1, Mid- Atlantic), when plant fluids are moving upwards to
support new growth, are questionable. Application during the summer (June 1- September 15, Mid - Atlantic) works very
well as long as vegetation is not a hindrance, and allows lower concentrations of herbicide to be used. Fall to mid - winter
applications (October- January) have given poor results. Mix up a solution of 20% (as low as 10% in summer depending
on objectives) concentration of oil - soluble triclopyr product (e.g., Garlorg 4) in 80% oil (fuel oil, diesel, kerosene, mineral
oil, or special vegetable oils). With these diluents some applicators add a pine oil based additive (e.g., Cide- Kick ®11) at
the rate of 10 %, which helps penetrate the bark and eliminate any unpleasant odor. Some companies market diluents
based on mineral or vegetable oils specifically designed for basal bark application, which should be considered for use in
sensitive areas. Another option is to use a pre- mixed, ready -to-use triclopyr product designed for basal bark (and cut
stump) application (e.g., PalhfnderO II). Using a handheld or backpack type sprayer, apply the mixture in a 12 inch wide
band around the entire circumference of the tree base with no "skips'. The basal bark method is generally used for trees
that are less than 6 inches in diameter, though slightly larger stems may also be treated effectively by thoroughly treating
bark up to 24 inches in height. Follow -up foliar herbicide application (see above) to basal sprouts and root suckers may be
necessary. Another herbicide which has been shown to be effective for basal bark control of ailanthus is imazapyr (e.g.,
Chopped, Stalker(D). This is sometimes used in a combination with triclopyr at a concentration of 15% Gadon® 4 and 5%
Stalker® in 80% oil dilutant.
The hack - and -squirt or injection method is very effective and minimizes sprouting and suckering when applied during the
summer. Root suckering will be an increasing problem in the fall, winter and spring. This method requires first making
downward- angled cuts into the sapwood around the tree trunk at a comfortable height, using a hand ax. With spray bottle
or wand in the other hand, squirt a straight (100 %) concentration of a water - soluble triclopyr product (e.g., Gadon® 3A)
into the cuts within a minute or two, applying 1 -2 milliliters into each cut (typically 1 -2 squirts of a trigger squirt bottle) so
that the bottom of the cut is covered, but liquid doesn't con out of it. Generally, you would make about 1 hack out for each
inch of diameter plus one (i.e., for a 10 inch diameter tree, make about 11 cuts). Space the cuts so that about 1 -2 inches
of uncut living tissue remains between them. A continuous line of cuts around the trunk would likely cause the tree to go
into emergency response mode and react by producing basal sprouts and root suckers. For this reason, girdling or frilling
(girdling followed by herbicide) is not highly recommended unless long tens follow -up treatment is possible. While spaced
injection works well for ailanthus, it is not as effective on some other species. This method can be used with trees of any
size, though it is most productive with stems over 2 inches in diameter. This method is relatively easy for one person to
do, with hatchet in one hand and spray bottle in the other, but should be done with a buddy nearby in case of an accident.
Monitor the treatment area and be prepared to follow -up with a foliar application the next year to control any basal sprouts
or root suckers that might emerge. Gyyphosate products have sometimes been recommended for control of ailanthus
using this method, but several field trials have shown consistently poor long -term control of basal sprouts and root suckers
at any time of year. Other herbicides which have shown to be effective for hack- and -squirt control of ailanthus during the
growing season are dicamba (e.g., Banvel®, Vanquish ®), imazapyr (e.g., Arsenal® A.C., Chopper®), and 2,4 -D +
picloram (e.g., Pathway®). Dicamba is particularly effective in October.
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The cut stump method is useful in areas where the trees need to be removed from the site and will be cut as part of the
process. While situations exist that dictate this method over the others given above, felling trees is usually less effective in
killing the root system, slower, more labor intensive, and more hazardous to personnel than other methods. This method
is likely to be most successful during the growing season, With diminishing success through the early fall. Dormant season
applications may prevent resprouting from the stump itself, but will do little to inhibit root suckering. However, at any time
of year, if the tree must be cut it is better to treat the stump than not. Application of herbicide to the cut slumps must be
Conducted immediately after cutting, within 5 -15 minutes of the cut with water soluble formulations, longer with oil
mixtures, to ensure uptake of the chemical before the plant seals the cut area off. The mixture may be painted on with a
paint brush or sprayed on using a spray bottle or backpack sprayer. A mixture of 20% Garlon® 4 plus 80% oil dilutent, as
for basal bark spraying (above), may be used. In this case the whole stump surface and sides to the ground line would be
sprayed. Another option is to use Garlor& 3A at 100 %, treating only the outer 113 of the stump surface. Be prepared to
follow -up with a foliar application the next year to Control any stump sprouts or root suckers which emerge. Other
herbicides which have shown to be effective in stump treatment of ailanthus are the same as those listed above for hack
and squirt or injection.
USE PESTICIDES WISELY: Always read the entire pesticide label carefully, follow all mixing and application instructions and wear all i
[ recommended personal protective gear and clothing. Contact your state department of agriculture for any additional pesticide use i
requirements mstrictions or recommendations. [
1 NOTICE: mention of pesticide products on this page does not constitute endorsement of any material. ]
CONTACTS
For more information on the management of Tree -0f - heaven, please Contact:
• Philip D. Pannill, U.S. Fish and Wildlife Service, Shepherdstown, WV; phil—parmill (at) tws.gov
• Jil Swearingen, National Park Service, Center for Urban Ecology, Washington, DC; jil_swearingen (at) nps.gov
SUGGESTED ALTERNATIVE PLANTS
Many lovely native trees and shrubs make excellent substitutes for Ailanthus and are readily available. Some examples
for the eastern United States include deciduous shrubs such as staghom sumac (Rhus typhina), smooth sumac (Rhus
glabra), fringe -tree (Chionanthus virginicus), black walnut (Juglans nigm), butternut (Juglans cinema) and hickories
(Carya). Whenever possible, use plant species that are native and adapted to the ecological region where you live. They
will be more valuable to the wildlife species that have evolved with them and depend upon them for food and shelter.
Check with your local native plant society for recommendations and sources of native plants.
OTHER LINKS
• http:IAw . invasive .org /searchlaction.cfm ?q= Ailanthus %20altissima
• http:// nbii- nin.ciesin. Columbia. eduripanefiiceVbrowse .do ?specield =30
AUTHORS
Jil M. Swearingen, National Park Service, Center for Urban Ecology, Washington, DC
Philip D. Pannill, U.S. Fish and Wildlife Service, National Conservation Training Center, Shepherdslown, WV
PHOTOGRAPHS
Olivia Kwong, Plant Conservation Alliance, Washington, DC
Jil M. Swearingen, National Park Service, Washington, DC
REFERENCES
Bory, G. and D. Clair- Maczulajtys. 1980. Production, disseminatlon and polymorphism of seeds in Ailanthus altissime.
Revue Generale de Botanique 88(1049/1051): 297 -311 [in French].
Elias, T. 1980. The Complete Trees of North America: Field Guide and Natural History, Book Division, Times Mirror
Magazines, Inc. New York.
Gleason, H.A., and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada.
New York Botanical Garden, Bronx, New York.
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Weeds Cxone Wild: Allen Plant invaders of Natural Areas
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Hu, S.Y. 1979. Ailanthus. Arnoldia 39(2): 29 -50,
Kaufmann, S.R. and W. Kaufmann. 2007. Invasive Plants: Guide to Identification and the Impacts and Control of Common
North American Species. Stackpole Books. 458 pp.
Mergen, F. 1959. A toxic principle in the leaves of Ailanthus. Bot. Gazette 121: 32 -36.
Pannill, Philip, 1995. Tree -of- Heaven Control. Maryland Department of Natural Resources Forest Service Stewardship
Bulletin. 8 pp.
Randall, J.M. and J. Marinelli. 1996, Invasive Plants: Weeds of the Global Garden. Brooklyn Botanic Garden, Handbook
#149. 111 pp.
Scholl, M.J. and D. D. Davis. 2009. Ailanthus a/tissima wilt and mortality: etiology. Plant Disease vol 93, no.7, pp. 747-
751. http: / /apsjournals .apsnet.org/doi /abs/t0. 1094 / PDIS- 93- 7- 0747?wokieSst= 1 &journalCode =pdis
Swearingen, J. 2009. WeedUS Database of Plants Invading Natural Areas in the United States: Tree-0f- Heaven
( Aflanthus alhssima). http: /Aw . invasive.orgAvedus /subject.html ?sub =3003
Tennessee Exotic Pest Plant Council. Tree of Heaven. Tennessee Exotic Plant Management Manual. 1996
The Nature Conservancy, California Regional Office. November 1988. Ailanthus alffssima Element Stewardship Abstract
Report (prepared by Marc Hoshovsky). Arlington, Virginia.
Virginia Department of Conservation and Recreation and Virginia Native Plant Society. 1996. Invasive Alien Plant Species
of Virginia: Tree-of- Heaven (Ailanthus alfissima (Miller) Swingle).
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Plant Conservation Alliance's Alien Plant Working Group
Weeds'ixone'✓a{`fld: Alien Plmt Inved. oS Natural Areas
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