Empress tree (Paulownia tomentosa)

Present distribution

Scientific name:	Paulownia tomentosa (Thunb.) Steud.
Common name(s):	empress tree

Map showing the present distribution of this weed.

Habitat:

Invades forests, stream banks & steep rocky slopes (NPS 2009); Very frost hardy, tolerates drought conditions (Burnie et al. 1997); Not fussy about soil type (Wiki 2009). Succeeded when shaded by taller trees (Wiki 2009); Resilient to frost, needs well drained soil (AUGA 2009); Tolerates high soil acidity, drought and low soil fertility (GISD 2009). Along water courses (GISD 2009), Dry southern aspects (FSFED 2009); Woods W. China 1300 – 2000m (PFAF 2009).

Potential distribution

Potential distribution produced from CLIMATE modelling refined by applying suitable landuse and vegetation type overlays with CMA boundaries

Map Overlays Used

Land Use:
Forestry

Ecological Vegetation Divisions
Lowland forest; foothills forest; forby forest; damp forest; riparian; wet forest; rainforest; high altitude shrubland/woodland; granitic hillslopes; rocky outcrop shrubland; semi-arid woodland; alluvial plains woodland; riverine woodland/forest

Colours indicate possibility of Paulownia tomentosa infesting these areas.

In the non-coloured areas the plant is unlikely to establish as the climate, soil or landuse is not presently suitable.

map showing the potential distribution of paulownia tomentosa

Red= Very high	Orange = Medium
Yellow = High	Green = Likely

Impact

QUESTION	COMMENTS	RATING	CONFIDENCE
Social
1. Restrict human access?	Tree which grows to a height of 15m and a width of 10m (AUGA 2009). Princess tree is an aggressive ornamental tree that grows rapidly in disturbed natural areas, including forests, stream banks, and steep rocky slopes (NPS 2009). Forms dense thickets: No (PIER 2009). Unlikely to restrict access to a major degree. Minimal or negligible impact (ie. can go anywhere).	L	MH
2. Reduce tourism?	Branches tend to be brittle (PFF 2009). Messy tree (NCS 2002). Minor effects to aesthetics and/or recreational uses (ie. aware but not bothered or activity inhibited).	ML	MH
3. Injurious to people?	Parts of plant are poisonous if ingested (DG 2009). Unpalatable to grazing animals: No (PIER 2009). Conflicting evidence.	M	L
4. Damage to cultural sites?	Generally has a shallow root system (FSFED 2009). May cause some minor structural damage to paths/ walkways. Moderate structural effect.	MH	M
Abiotic
5. Impact flow?	It is / is important for the soil to be well drained (AUGA 2009). Also occurs along water courses (GISD 2009). Branches tend to be brittle (PFF 2009). Messy tree (NCS 2002). Some litter obstruction to water flow is likely. Minor impact on surface or subsurface flow either by roots or free floating aquatics.	ML	M
6. Impact water quality?	It is important for the soil to be well drained (AUGA 2009). Also occurs along water courses (GISD 2009). Minor reduction in light levels.	ML	M
7. Increase soil erosion?	The tree thrives on dry southern aspects, even though it generally has a shallow root system (FSFED 2009). Soil erosion is likely if tree topples after heavy rain. Moderate probability of large scale soil movement.	ML	M
8. Reduce biomass?	Princess tree is an aggressive ornamental tree that grows rapidly in disturbed natural areas, including forests, stream banks, and steep rocky slopes (NPS 2009). Forms dense thickets: No (PIER 2009). Unlikely to reduce biomass. Direct replacement of biomass by invader.	ML	M
9. Change fire regime?	Paulownia tomentosa can survive wildfire because the roots can regenerate new, very fast-growing stems (Wiki 2009). Probably increase fire intensity/ frequency as a very fast growing source of fuel. Moderate change to both frequency and intensity of fire risk.	MH	M
Community Habitat
10. Impact on composition (a) high value EVC	EVC = Sub-alpine Treeless Mosaic (V); CMA = North east; Bioregion =Victorian Alps; VH CLIMATE potential. Paulownia is succeeded by taller trees that shade it. It cannot thrive in the shade of other trees (Wiki 2009). Forms dense thickets: No (PIER 2009). Minor displacement of some dominant or indicator spp. within any one strata/layer (e.g. ground cover, forbs, shrubs, & trees).	ML	MH
(b) medium value EVC	EVC = Grassy Dry Forest (D); CMA =North East; Bioregion =Northern Inland Slopes; VH CLIMATE potential. Paulownia is succeeded by taller trees that shade it. It cannot thrive in the shade of other trees (Wiki 2009). Forms dense thickets: No (PIER 2009). Minor displacement of some dominant or indicator spp. within any one strata/layer (e.g. ground cover, forbs, shrubs, & trees). Minor displacement of some dominant or indicator spp. within any one strata/layer (e.g. ground cover, forbs, shrubs, & trees).	ML	MH
(c) low value EVC	EVC = Montane Rocky Shrubland (LC); CMA =East Gippsland; Bioregion =Victorian Alps; VH CLIMATE potential. Paulownia is succeeded by taller trees that shade it. It cannot thrive in the shade of other trees (Wiki 2009). Forms dense thickets: No (PIER 2009). Very little displacement of any indigenous spp. Sparse/ scattered infestations.	L	MH
11. Impact on structure?	Paulownia is succeeded by taller trees that shade it. It cannot thrive in the shade of other trees (Wiki 2009). Forms dense thickets: No (PIER 2009). Minor effect on 20-60% of the floral strata.	ML	M
12. Effect on threatened flora?	Can also colonise rocky cliffs and scoured riparian zones where it may compete with rare plants in these marginal habitats (GISD 2009). Any population of a VROT spp is reduced.	ML	M
Fauna
13. Effect on threatened fauna?	May outcompete/ reduce numbers of native tree species reducing food availability. Minor effects on threatened spp.; minor hazard or reduction in habitat/food/ shelter.	ML	ML
14. Effect on non-threatened fauna?	May outcompete/ reduce numbers of native tree species reducing food availability. Minor effects on fauna spp.; minor hazard or reduction in habitat/food/ shelter.	ML	M
15. Benefits fauna?	Parts of plant are poisonous if ingested (DG 2009). Unpalatable to grazing animals: No (PIER 2009). Conflicting evidence. Provides shade/ shelter. Provides some assistance in either food or shelter to desirable species.	MH	MH
16. Injurious to fauna?	Produces spines, burrs, thorns: No; Unpalatable to grazing animals: No (PIER 2009). Parts of plant are poisonous if ingested (DG 2009). Its nitrogen-rich leaves provide good fodder (Wiki 2009). Conflicting evidence.	M	L
Pest Animal
17. Food source to pests?	Its nitrogen-rich leaves provide good fodder (Wiki 2009). Parts of plant are poisonous if ingested (DG 2009). Not enough information.	M	L
18. Provides harbour?	Effective natural enemies present in Australia: No (PIER 2009). Tree – unlikely to be able to provide shelter to foxes and/or rabbits. Doesn’t provide harbour for serious pest spp, but may provide for minor pest spp.	ML	M
Agriculture
19. Impact yield?	Not reported to be a weed of agriculture. Unlikely to affect livestock or crops.	M	L
20. Impact quality?	Not reported to be a weed of agriculture. Unlikely to affect livestock or crops.	M	L
21. Affect land value?	Not reported to be a weed of agriculture. Unlikely to affect land value. Little or none.	L	M
22. Change land use?	Princess tree can be controlled using a variety of mechanical and chemical controls (NPS 2009). Unlikely to change land use. Little or no change.	L	M
23. Increase harvest costs?	Not reported to be a weed of agriculture. If control is necessary then it is likely to increase production costs. Minor increase in cost of harvesting – eg slightly more time or labour is required.	ML	ML
24. Disease host/vector?	No major pests/diseases are known for this species in the US (FSFED 2009). None reported for Australia.	L	ML

Invasive

QUESTION	COMMENTS	RATING	CONFIDENCE
Establishment
1. Germination requirements?	Seed – best sown as soon as it is ripe in a cold frame (PFF 2002). May germinate shortly after reaching a suitable soil (NPS 2002). Requires natural seasonal disturbances such as seasonal rainfall, spring/summer temperatures for germination.	MH	M
2. Establishment requirements?	Seedlings are very intolerant of shade – referring to full shade (FSFED 2002). Requires more specific requirements to establish (eg. open space or bare ground with access to light and direct rainfall).	ML	MH
3. How much disturbance is required?	Invades forests, stream banks & steep rocky slopes (NPS 2002). Establishes in relatively intact or only minor disturbed natural ecosystems (eg. wetlands, riparian, riverine, grasslands, open woodlands); in vigorously growing crops or in well-established pastures.	MH	M
Growth/Competitive
4. Life form?	Tree which grows to a height of 15m and a width of 10m (AUGA 2009). Other.	L	H
5. Allelopathic properties?	No allelopathic properties described.	M	L
6. Tolerates herb pressure?	Trees can be coppiced annually (PFF 2002). Its ability to sprout prolifically from adventitious buds on stems & roots allows it to survive…cutting & even bulldozing. (NPS 2002). Consumed but non-preferred or consumed but recovers quickly; capable of flowering /seed production under moderate herbivory pressure.	MH	MH
7. Normal growth rate?	In China, an old custom is to plant an Empress Tree when a baby girl is born. The fast-growing tree matures when she does (Wiki 2009). “An aggressive ornamental tree that grows rapidly.” (NPS 2002). Rapid growth rate that will exceed most other species of the same life form.	H	H
8. Stress tolerance to frost, drought, w/logg, sal. etc?	Paulownia tomentosa can survive wildfire because the roots can regenerate new, very fast-growing stems. It is tolerant of pollution and it is not fussy about soil type (WIKI 2009). Paulownia is succeeded by taller trees that shade it. It cannot thrive in the shade of other trees (Wiki 2009). Quite resilient to frost, It is / is important for the soil to be well drained (AUGA 2009). “Tolerates high soil acidity, drought, and low soil fertility” (GISD 2009). Highly tolerant of at least two of drought, frost, fire, waterlogging, and salinity, and may be tolerant of another. Susceptible to at least one.	MH	MH
Reproduction
9. Reproductive system	The flowers from this plant are hermaphrodite (has both male and female organs) (AUGA 2009). Seeds and suckers (Webb et al. 1988). Both vegetative and sexual reproduction.	H	MH
10. Number of propagules produced?	The fruit is a dry egg-shaped capsule 3-4 cm long, containing numerous tiny seeds (Wiki 2009). Paulownia produces millions of small fluffy seeds formerly used as packing material (PAOR 2009). Several thousand tiny winged seeds (NPS 2002). Above 2000.	H	H
11. Propagule longevity?	“Seeds can remain in seed bank for at least 3 years” (GISD 2009). Greater than 25% of seeds survive 5 years, or vegetatively reproduces.	L	MH
12. Reproductive period?	“Mature trees are often structurally unsound & rarely live more than 70 years”. 70-10 = 60 years for reproducing. (NPS 2009). Mature plant produces viable propagules for 10 years or more.	H	H
13. Time to reproductive maturity?	“Seedlings grow quickly & flower in 8-10 years” (NPS 2009). Greater than 5 years to reach sexual maturity. No information on age until it produces vegetative offspring.	L	M
Dispersal
14. Number of mechanisms?	The seeds are winged and disperse by wind and water (Wiki 2009). Spread by seed and suckering (WDAU 2009). A single tree is capable of producing an estimated twenty million seeds that are easily transported long distances by wind and water (NPS 2009). Very light, wind dispersed seeds	H	H
15. How far do they disperse?	Easily transported long distances by wind and water (NPS 2009). Very likely that at least one propagule will disperse greater one kilometre.	H	H

References

AUGA (2009) Aussie Gardening. Available at http://www.aussiegardening.com.au/findplants/plant/Paulownia_tomentosa (verified 05/2009).

Burnie G, Forrester S, Grieg D, Guest S, Harmony M, Hobley S, Hackson G, Lavarack P, Ledgett M, McDonald R, Macoboy S, Molyneux B, Moodie D, Moore J, Newman D, North T, Pienaar K, Purdy G, Silk J, Ryan S, Schien G (1997) Botanica Random House. Milsons Point, NSW.

DG (2009) Daves Garden. Available at http://davesgarden.com/guides/pf/go/391/ (verified 05/2009).

FSFED (2002) USDA Forest Service. Available at http://www.na.fs.fed.us/pubs/silvics_manual/Volume_2/paulownia/tomentosa.htm (verified 05/2009).

GISD (2009) Global Invasive species Database. Available at http://www.issg.org/database/species/ecology.asp?fr=1&si=440 (verified 05/2009).

NCS (2009) NC State University. Available at http://www.ces.ncsu.edu/depts/hort/consumer/factsheets/trees-new/paulownia_tomentosa.html (verified 05/2009).

NPS (2002) PCA Alien Plant Working Group – princess Tree (Paulownia tomentosa) Available at http://www.nps.gov/plants/alien/fact/pato1.htm (verified 02/2009).

PAOR (2009) Paulownia.org. Available at http://www.paulownia.org/ (verified 05/2009).

PIER (2009) Pacific Island Ecosystems at Risk. Paulownia tomentosa. Weed risk assessment. Available at http://www.hear.org/pier/wra/pacific/paulownia_tomentosa_htmlwra.htm (verified 05/2009).

WDAU (2009). Weeds.org.au: Weeds Australia: weed Identification. Available at http://www.weeds.org.au/cgi-bin/weedident.cgi?tpl=plant.tpl&state=&s=&ibra=all&card=T46 (verified 05/2009).

Wiki (2009) Wikipedia - Paulownia tomentose. Available at http://en.wikipedia.org/wiki/Paulownia_tomentosa. (verified 05/2009).

Global present distribution data references

Australian Plant Name Index (APNI) http://www.cpbr.gov.au/cgi-bin/apni (26/03/2009).

Australian National Herbarium (ANH) (2008) Australia’s Virtual Herbarium, Australian National Herbarium, Centre for Plant Diversity and Research, Available at
http://www.anbg.gov.au/avh/ (verified 17/02/2009).

Department of the Environment and Heritage (Commonwealth of Australia). (1993 – On-going) Australian Plant Name Index (APNI) http://www.cpbr.gov.au/apni/index.html (verified 07/05/2009).

Global Biodiversity Information Facility (GBIF) (2008) Global biodiversity information facility, Available at http://www.gbif.org/ (verified 17/02/2009).

Integrated Taxonomic Information System. (2009) Available at http://www.itis.gov/ (verified 07/05/2009).

Missouri Botanical Gardens (MBG) (2009) w³TROPICOS, Missouri Botanical Gardens Database, Available at http://mobot.mobot.org/W3T/Search/vast.html
(viewed 17/02/2009).

United States Department of Agriculture. Agricultural Research Service, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) [Online Database]. Taxonomy Query. (2009) Available at http://www.ars-grin.gov/cgi-bin/npgs/html/taxgenform.pl (verified 26/03/2009).

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