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princess tree

Paulownia tomentosa

Description and biology 8

  • Plant: medium-sized deciduous tree that grows to 30-60 ft. in height; twigs are stout, green to brown, and have many lenticels; bark is thin, gray-brown with shallow features.
  • Leaves: paired, large, hairy on upper surfaces, broadly oval to heart-shaped and sometimes shallowly three-lobed.
  • Flowers, fruits and seeds: flowers are showy, pale violet and fragrant and produced in conspicuous upright clusters in spring before the leaves appear; fruit is a four-compartmented oval capsule containing thousands of small winged seeds; capsules green, becoming brown and dry as they mature and persist through the winter.
  • Spreads: by seed which is abundant and easily transported long distances by wind and water; a single tree is estimated to produce twenty million seeds; seeds germinate easily in suitable soil; seedlings grow and mature quickly, producing flowers within 8-10 years.

Ecological threat in the united states 9

Princess tree is an aggressive ornamental tree that grows rapidly in disturbed natural areas, including forests, streambanks, and steep rocky slopes.

Impacts and control 10

More info for the terms: cover, fire management, interference, invasive species, natural, nonnative species, prescribed fire, presence, stringer, tree, xeric

Impacts: Princesstree is a moderate to severe threat to native plant communities in many eastern states. In general, it is considered moderately invasive in native communities of the northeastern United States [137]. In the Southeast, it is typically considered a substantial or severe threat to native communities [1,47,75,80,120,121]. Princesstree is considered moderately invasive in Virginia [142]. In a study using the Southern Research Stations Forest Inventory and Analysis database, cover estimates of princesstree totaled over 20,000 acres in 12 southeastern states [97]:
Estimates of area covered by princesstree in the Southeast as of 2008 [97] State Acres Alabama 2,284 Arkansas 82 Florida 82 Georgia 347 Kentucky 2,726 Louisiana 7 Mississippi 1,867 North Carolina 2,297 South Carolina 95 Tennessee 7,361 Texas (east) Not detected Virginia 6,331 Total acres covered 23,478

Princesstree is primarily a threat to native communities in heavily disturbed areas in the eastern United States. In the southern Appalachian Mountains it excludes native species in areas that experience frequent fire or in areas with naturally exposed soils and sunny aspects such as cliffs and rocky outcrops (see Site Characteristics) [70,84]. In the Great Smoky Mountains National Park and Linville Gorge Wilderness Area, its ability to colonize rocky or infertile sites makes it a threat to 2 rare, endangered species (Heller's blazing star (Liatris helleri), mountain goldenheather (Hudsonia montana)) that require these marginal habitats [44,79]. Its ability to sprout or establish by seed quickly after fire has allowed princesstree to replace native fire-dependent species such as Table Mountain pine and pitch pine in some areas of Great Smoky Mountains National Park [118].

Many studies report princesstree is of minor importance in intact forest and undisturbed environments [37]. For example, in New London County, Connecticut, it had increased in disturbed areas but had not spread to more mature plant associations; the remaining native terrestrial flora had not seriously declined despite a high percentage of nonnative species [59]. In western North Carolina and eastern Tennessee, there was no significant correlation between princesstree's presence or cover and native species cover or diversity; however, the author cautioned about the stability of this condition if princesstree cover were to increase [79]. Princesstree was not considered an "aggressive invader" in eastern forests lacking large-scale disturbance due to its habit of forming "small scattered populations in much the same way that it does in its natural environments in China" [147]. In China, Hu [63] speculated that the requirement for high light for germination and the small size of the seed—with little food reserve—probably contribute to the isolated occurrence of princesstrees there.

Kuppinger [79] concluded that princesstree in western North Carolina and eastern Tennessee "appears to be able to germinate and survive for a year or 2 across a much larger range of habitat conditions than will enable it to survive to maturity". The author continued by stating that "in situations where there is interest and resources for control efforts, (habitat models) indicate that control may be unnecessary over large portions of the landscape initially invaded by princesstree. In these areas, it is likely that regeneration of native vegetation will eventually exclude princesstree as it is apparently a poor competitor for space and light. Because of this, control efforts should be focused on the most xeric and exposed portions of the landscape where habitat models predict princesstree will persist and a high-light, low-competition environments will be maintained" [79].

Control: Princesstree control requires persistence due to its strong sprouting ability, rapid growth, and prolific seed production. Posttreatment monitoring and retreatment are essential. Treated areas should be checked once or more a year, with any new sprouts or seedlings retreated (cut, sprayed, or pulled) as soon as possible so that roots do not have time to build up carbohydrate reserves and grow larger. Princesstree's rapid root growth and sprouting ability underscore the need to eradicate seedlings when they are small and before they become established.

In all cases where invasive species are targeted for control, no matter what method is employed, the potential for other invasive species to fill their void must be considered [21]. Bean and others [10] review application methods for many of the control methods discussed below; however, the information provided herein is not intended to be either comprehensive or prescriptive in nature.

Fire: For information on the use of prescribed fire to control this species, see Fire Management Considerations.

Prevention: Managing to maintain the integrity of the native plant community and mitigate the factors enhancing ecosystem invasibility is likely to be more effective than managing solely to control the invader [60]. Maintaining high plant species richness in native communities is likely to decrease the invasibility of plant communities by princesstree because interference from neighboring vegetation may decrease princesstree's growth and survival (see Successional Status). Due to princesstree's preference for open, disturbed habitat, its establishment may be prevented by minimizing loss or disturbance of native communities [99,103]. For example, Williams [146] surmised that since light levels may be inadequate for the growth and survival of princesstree seedlings or sprouts, small forest gaps are unlikely to contribute to its population maintenance in most forests, whereas native early-successional forest trees such as yellow-poplar and black birch may occupy canopy gaps of various sizes [146]. Given this, planting of native species in the understory of existing stands may allow native species to increase while preventing princesstree germination [90].

Successful control of princesstree requires prevention of propagation and planting by restricting the sale and use of princesstree and increasing public education about its impacts on native communities. In 2006, Webster and others [144] stated that "a quick review of the forestry extension web sites of 24 land grant universities in the eastern United States revealed that 7 institutions still offer publications that promote invasive exotic woody plants for plantations, wildlife habitat improvement, and ornamental plantations". The authors suggest that the first step in preventing the introduction of princesstree is by "encouraging the use of native species in forestry and horticulture applications" [144].

Another method of preventing princesstree infestation is by developing and using a risk assessment model [35]. A risk assessment model combines information regarding current infestations with what is known about the species' biology. Land managers can then use the model to identify the probability of occurrence and areas at risk of invasion. Although a risk assessment model had not been developed for princesstree in the United States as of this writing (2009), McNab and Loftis [94] developed a model for oriental bittersweet (Celastrus orbiculatus) and suggested that such a model could be broadly applicable to princesstree and other invasive plants.

Weed prevention and control can be incorporated into many types of management plans, including those for logging and site preparation, grazing allotments, recreation management, research projects, road building and maintenance, and fire management [139]. See the Guide to noxious weed prevention practices for specific guidelines in preventing the spread of weed seeds and propagules under different management conditions.

Physical and/or mechanical: Mechanical methods can be an effective initial control measure for princesstree. Cut mature trees at ground level. To prevent seed production, cutting is most effective at the onset of flowering. Because princesstree spreads by suckering, root sprouts are common after treatment, and additional control methods such as repeated cutting for sprouts or an herbicidal control to prevent sprouting may be required [10]. Repeated cutting eventually exhausts the roots and kills the plant, but this may take several years [71]. Girdling kills the top of a tree but sprouts are common and may require a follow-up treatment with a foliar herbicide such as glyphosate or triclopyr. Seedlings can be controlled by hand-pulling; however, the entire root must be removed because broken root fragments may sprout [10].

Biological: Biocontrol could potentially reduce the invasiveness of princesstree in the United States [42], but no biocontrol methods are available as of this writing (2009). Ding and others [35] prioritized princesstree and 9 other species as targets for future biological control efforts based on information on their importance in introduced areas, availability of their host-specific insects or pathogens in China, and their potential biological control risk to introduced ecosystems. According to this study, princesstree has no congener species in the United States, making the potential biological control risk to introduced ecosystems low. Of 128 natural enemies in China, 19 may be potential biological control agents for use in the United States due to their narrow host ranges.

Biological control of invasive species has a long history that indicates many factors must be considered before using biological controls. Refer to these sources [141,151] and the Weed control methods handbook [135] for background information and important considerations for developing and implementing biological control programs.

In the United States, native and nonnative invertebrates, fungi, and diseases are known to adversely affect princesstree. Several studies have reported mortality of seedlings due to root rots [13,62,63,123,127,138]. Stringer [127] described 2 fungi (Rhizoctonia sp., Colletotrichum sp.) that infected seedlings and caused die-back in field experiments in Kentucky. Several foliage diseases causing at least superficial damage to princesstrees have been reported in the United States, including Phyllosticta paulowniae, Phyllactinia guttata, and Uncinula clintonii ([70], Hepting 1971, cited in [16]). Princesstree is subject to minor damage by the Comstock mealybug (Pseudococcus comstocki), an introduced species from Asia [138] and saltmarsh caterpillar (Estigmene acrea), a native species [15].

Chemical: Herbicides may provide initial control of a new invasion or a severe infestation but are rarely a complete or long-term solution to invasive species management [23]. Herbicides are more effective on large infestations when incorporated into long-term management plans that include replacement of weeds with desirable species, careful land use management, and prevention of new infestations. Following stem control, total elimination requires surveillance and treatment of root sprouts and plant germinants that originate from the soil seed bank [96]. Control with herbicides is temporary because it does not change conditions that allow infestations to occur [156]. See The Nature Conservancy's Weed control methods handbook [135] for consideration on the use of herbicides in wildlands and detailed information on specific chemicals.

According to reviews, systemic herbicides (e.g., triclopyr and glyphosate), which kill roots, currently provide the best chemical control for princesstree [10], although results may vary depending upon environmental conditions. These herbicides risk damage to nontarget species. When princesstree is interspersed with nontarget species, the foliage, stumps, or basal bark of individual trees can be treated with herbicides [10]. Integrated management: Princesstree can be controlled most effectively using integrated management. Cutting or girdling trees may prevent seed production. However, princesstree readily sprouts and repeated cutting or an herbicide treatment following cutting may be necessary [134]. Korostoff [77] reports that princesstree was eliminated in northwestern Pennsylvania by cutting followed by stump treatment with herbicide. Integrated management should include establishing desirable species in addition to considerations for killing the target plant.

Prevention and control 11

Do not plant princess tree. Young plants can be pulled by hand; cut larger trees at ground level with power or manual saw, preferably prior to seed formation to prevent further spread. Systemic herbicides containing glyphosate or triclopyr are effective and can be applied to cut stumps or to bark.

Sources and Credits

  1. (c) Matthew Allen, some rights reserved (CC BY-NC), uploaded by Matthew Allen
  2. (c) cwwood, some rights reserved (CC BY-SA), uploaded by cwwood
  3. (c) Jenny Glenn, some rights reserved (CC BY-NC), uploaded by Jenny Glenn
  4. (c) Susan J. Hewitt, some rights reserved (CC BY-NC), uploaded by Susan J. Hewitt
  5. (c) Matt Parr, some rights reserved (CC BY-NC), uploaded by Matt Parr
  6. (c) kittiesrtbst, some rights reserved (CC BY-NC)
  7. (c) Sporange, some rights reserved (CC BY-NC), uploaded by Sporange
  8. (c) Unknown, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22733947
  9. (c) Unknown, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22948750
  10. Public Domain, http://eol.org/data_objects/25573818
  11. (c) Unknown, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/22733948

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