Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service

Information on Risk Assessments
Original risk assessment

Paulownia tomentosa (princess tree, empress tree)

Answer

1.01

Is the species highly domesticated?

y=-3, n=0

n

1.02

Has the species become naturalized where grown?

y=-1, n=-1

y

1.03

Does the species have weedy races?

y=-1, n=-1

n

2.01

Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical”

See Append 2

1

2.02

Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2

1

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

y

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

2.05

Does the species have a history of repeated introductions outside its natural range? y=-2

?=-1, n=0

y

3.01

Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05

y

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

y

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

n

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

y

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

n

4.01

Produces spines, thorns or burrs

y=1, n=0

n

4.02

Allelopathic

y=1, n=0

n

4.03

Parasitic

y=1, n=0

n

4.04

Unpalatable to grazing animals

y=1, n=-1

n

4.05

Toxic to animals

y=1, n=0

n

4.06

Host for recognized pests and pathogens

y=1, n=0

n

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

n

4.1

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

4.11

Climbing or smothering growth habit

y=1, n=0

n

4.12

Forms dense thickets

y=1, n=0

n

5.01

Aquatic

y=5, n=0

n

5.02

Grass

y=1, n=0

n

5.03

Nitrogen fixing woody plant

y=1, n=0

n

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

n

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

6.02

Produces viable seed.

y=1, n=-1

y

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

6.05

Requires specialist pollinators

y=-1, n=0

n

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

8

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

n

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

7.04

Propagules adapted to wind dispersal

y=1, n=-1

y

7.05

Propagules water dispersed

y=1, n=-1

y

7.06

Propagules bird dispersed

y=1, n=-1

n

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

n

7.08

Propagules survive passage through the gut

y=1, n=-1

n

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

y

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-1

y

8.03

Well controlled by herbicides

y=-1, n=1

y

8.04

Tolerates, or benefits from, mutilation, cultivation, or fire

y=1, n=-1

y

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

9

Source

Notes

1.01

No evidence

1.02

Considered weed in the United States.

http://www.nps.gov/plants/alien/fact/pato1.htm

1.03

No evidence

2.01

Native to China. It is a temperate species.

Plant Master 5.5 CD-ROM database.

2.02

2.03

USDA hardiness zones 5B - 9B.

Southern Trees. CD-ROM database.

2.04

Considered weed in the United States.

http://www.nps.gov/plants/alien/fact/pato1.htm

2.05

(1)Introduced to the U.S. (2)It has also been planted in some Pacific States. (3)Planted in India

(1)Southern Trees. CD-ROM database. (2)http://www.na.fs.fed.us/spfo/pubs/silvics_manual/volume_2/paulownia/tomentosa.htm (3)Arushi Mehrotra; Mehrotra, M. D.; Sachan, S. N. 1998. Effect of VAM, fertilizer and deoiled neem cake application on the growth of Paulownia tomentosa raised from root cuttings. Indian Journal of Forestry. Vol.21, No.2, pp.111-114, 4 ref.

3.01

This tree has since become naturalized in the eastern U.S. and is also grown on the west coast. Considered weed in the United States.

http://www.nps.gov/plants/alien/fact/pato1.htm

3.02

(1)'The tree is often considered a weed tree, and has naturalized in the edge of woodlands, along railroad rights-of-way, and in other areas of disturbed soil in eastern North America.' (2) 'The trees also cause maintenance problems along roads and utility rights-of-way and in gardens.'

(1)Horticopia A-Z. CD-ROM database. (2)http://www.hear.org/pier_v3.3/patom.htm

3.03

No evidence

3.04

It easily adapts to disturbed habitats, including previously burned areas, forests defoliated by pests (such as the gypsy moth) and landslides and can colonize rocky cliffs and scoured riparian zones where it may compete with rare plants in these marginal habitats.

http://www.nps.gov/plants/alien/fact/pato1.htm

3.05

No evidence

4.01

No evidence

Horticopia A-Z. CD-ROM database.

4.02

No evidence

Horticopia A-Z. CD-ROM database.

4.03

No evidence

4.04

Enriched in nutrients, paulownia leaves and flowers were good fodder for pigs, chicken, sheep, cattle and rabbits and so on.

http://www.idrc.ca/library/document/086352/086352ab.htm

4.05

Enriched in nutrients, paulownia leaves and flowers were good fodder for pigs, chicken, sheep, cattle and rabbits and so on. Results indicated that there were no any symptom of toxicity appeared.

http://www.idrc.ca/library/document/086352/086352ab.htm

4.06

No major insect pests are known for royal paulownia in the United States. No major disease problems have appeared yet in the United States.

http://www.na.fs.fed.us/spfo/pubs/silvics_manual/volume_2/paulownia/tomentosa.htm

4.07

No evidence

4.08

unlikely -- a single-trunked tree, does not grow in dense patches

4.09

(1)Requires full sun. (2)' For rapid growth to occur, the plant requires full sunlight …'

(1)Plant Master 5.5 CD-ROM database. (2)http://www.hear.org/pier_v3.3/patom.htm

4.1

(1)Grows in sandy, loam and clay soils. (2)It tolerates infertile and acid soils

(1)Plant Master 5.5 CD-ROM database. (2)http://www.nps.gov/plants/alien/fact/pato1.htm

4.11

Not a vine.

Plant Master 5.5 CD-ROM database.

4.12

No evidence

5.01

A 24 to 48 feet tall tree in Scrophulariaceae.

Plant Master 5.5 CD-ROM database.

5.02

5.03

5.04

6.01

Can reproduce from seed or from root sprouts.

http://www.nps.gov/plants/alien/fact/pato1.htm

6.02

Seedlings grow quickly and flower in 8-10 years.

http://www.nps.gov/plants/alien/fact/pato1.htm

6.03

[not natural] The height heterosis rate of each combination from high to low are P. fortunei X P. tomentosa, P. kawakamii X P. elongata., P. kawakamii X P. kawakamii, P. tomentosa X P. fortunei, P. kawakmii X P. fortunei and P. fortunei X P. kawkamii. In terms of ground diameter, the heterosis rate are P. kawkamii X P. kawakamii, P. kawakamii X P. elongata, P. kawakamii X P. tomentosa, P. fortunei X P. kawakamii and P. tomentosa X P. fortunei. These combinations could be used in future productions of paulownia.

http://www.idrc.ca/library/document/086352/086352b.htm

6.04

No information

6.05

Insect pollinated.

http://www.nps.gov/plants/alien/fact/pato1.htm

6.06

Princess tree can reproduce from seed or from root sprouts; the latter can grow more than 15 feet in a single season.

http://www.nps.gov/plants/alien/fact/pato1.htm

6.07

Seedlings grow quickly and flower in 8-10 years.

http://www.nps.gov/plants/alien/fact/pato1.htm

7.01

Probably not - the propagules do not have any means of attachment.

http://www.nps.gov/plants/alien/fact/pato1.htm

7.02

Horticulture-- 'Princess Tree should be planted where falling flowers and leaves are not objectionable because they can be a bit messy on hard surfaces. ….The tree can enhance any landscape with its delightful spring flush of foliage. It can be the centerpiece of your landscape if properly located. '

Horticopia A-Z. CD-ROM database.

7.03

No evidence

7.04

(1)A single tree is capable of producing an estimated twenty million seeds that are easily transported long distances by wind and water and may germinate shortly after reaching suitable soil. (2)Seeds winged.

(1)http://www.nps.gov/plants/alien/fact/pato1.htm (2)http://www.nobleplants.com/classnotes/fall/fallprofiles/paulownia.htm

7.05

A single tree is capable of producing an estimated twenty million seeds that are easily transported long distances by wind and water and may germinate shortly after reaching suitable soil.

http://www.nps.gov/plants/alien/fact/pato1.htm

7.06

No evidence

7.07

No evidence

7.08

No evidence of consumption

8.01

(1)capsule 3-4 cm long. Prolific seed producer (2)The fruit is a dry brown capsule with four compartments that may contain several thousand tiny winged seeds. … A single tree is capable of producing an estimated twenty million seeds that are easily transported long distances by wind and water and may germinate shortly after reaching suitable soil.

(1)http://www.hear.org/pier_v3.3/patom.htm (2)http://www.nps.gov/plants/alien/fact/pato1.htm

8.02

Three species (R. allegheniensis , Phytolacca americana and Paulownia tomentosa ) dominated the seed bank.

Hyatt, L. A.; Casper, B. B.2000. Seed bank formation during early secondary succession in a temperate deciduous forest. Journal of Ecology. 88: 516-527

8.03

'Chemical: Treat cut stumps immediately with a 50 percent solution of glyphosate or triclopyr herbicide to prevent sprouting. On small trees a foliar application of 2 percent glyphosate is effective.'

http://www.hear.org/pier_v3.3/patom.htm

8.04

(1)Mature plants can reproduce from coppice.
(2)The entire root must be removed since broken fragments may resprout.; . Its ability to sprout prolifically from adventitious buds on stems and roots allows it to survive fire

(1)http://www.hear.org/pier_v3.3/patom.htm (2)http://www.nps.gov/plants/alien/fact/pato1.htm

8.05

Don’t know.