Tung oil tree
Aleurites fordiiNon-Native in Florida |
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Tung oil treeIntroductionTung trees are cultivated primarily for their seeds, but it is also used as an ornamental plant in the landscape. The oils sequestered from the seed are used in the manufacture of lacquers, varnishes, paints, linoleum, oilcloth, resins, artificial leather, felt-base floor coverings, and greases, brake-linings and in clearing and polishing compounds. In its native land of China the seedlings have been planted for thousands of years. During World War II, the Chinese used tung oil for motor fuel. All parts of the tung tree are poisonous even though it has been used to treat skin conditions and constipation. The seeds are the most dangerous part of the plant. One seed can be fatal to a human. Symptoms may include severe stomach pain, vomiting, diarrhea, weakness, slowed breathing, and poor reflexes. The leaves give some people a poison-ivy-like rash. There are naturalized populations in the vicinities of Tallahassee, Gainesville, and Marianna; primarily from old plantations. Tung trees are also a problem on Cumberland Island in Georgia. The Florida Exotic Pest Plant Council has listed Aleurites fordii a Category II invasive exotic plant for Florida.
DescriptionTrees are deciduous and can grow up to 40 feet tall having smooth bark and soft wood. The heart-shaped, sometimes lobed, alternate leaves are dark green and up to 6 inches wide. This plant flowers before it produces its leaves. Flowers are white with a rose colored center and are borne in clusters arising from terminal buds of shoots from the previous season. Fruits are spherical or pear-shaped, green to purple at maturity, containing 4 to 5 seeds. Seeds have a hard outer shell and a kernel from which the oil is obtained. A distinguishing characteristic of tung oil tree are the presence of two red glands at the apices of the petiole.
ImpactsSpread is accomplished mainly through seed production. Fruit production begins when trees are 2 to 4 years old. Vegetation reproduction occurs with the formation of suckers from underground stems. Tung oil tree is able to grow in a wide array of environmental conditions, making it a successful, but slow invasive. Tung oil tree is listed as a Category II invasive species, but has not yet altered Florida plant communities to such an extent to be ranked a Category I invasive. Vouchered specimens have been reported in Northern and Central Florida.
Management
Preventative:The first step in preventative control of tung oil tree is to limit planting and removal of existing plants within the landscape. If possible, removal should occur before seeds are produced. Care must be exercised to prevent seed spread and dispersal during the removal process.
Cultural:Limited data on this aspect of control for tung trees.
Mechanical:Cut down larger trees. Hand pull seedlings before they mature. Remove all seeds from the area to prevent reinfestation.
Biological:Aphthona nigriscutis, a type of flea beetle, is a potential biological control agent for tung oil tree.
Chemical:Cut-stump and basal bark applications of triclopyr are effective, but retreatment is often necessary. Use 25% solution with diesel fuel for basal bark treatments. For cut stump treatments, apply 50% triclopyr solution within one minute of cutting. There is no research on the effectiveness of glyphosate for tung tree control.
References and Useful Links:University of Florida Center for Aquatic and Invasive Plants University of Florida’s Cooperative Extension Electronic Data Information Source Langeland, K.A. and K. Craddock Burks. 1998. Identification and Biology of Non-Native Plants in Florida's Natural Areas. IFAS Publication SP 257. University of Florida, Gainesville. 165 pp. Pacific Island Ecosystems at Risk (PIER). Plant Threats to Pacific Ecosystems Invasive Plants of the Eastern United States Excerpted from the University of Florida, IFAS Extension, Circular 1529, Invasive Species Management Plans for Florida, 2008 by: Greg MacDonald, Associate Professor Jay Ferrell, Assistant Professor and Extension Weed Specialist
More Resources:Read The History of Tung Oil by K. Brown and W. Keeler, Wildland Weeds, Winter 2005, 9(1):4-6. The UF/IFAS Assessment lists plants according to their invasive status in Florida.
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