Pacific Island Ecosystems at Risk (PIER)


Brachychiton acerifolius


RISK ASSESSMENT RESULTS: Low risk, score: -5


Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.

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

Brachychiton acerifolius (syn. Sterculina acerifolia); Illawarra flame tree, bottle 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

n

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

2

2.02

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

2

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

n

3.02

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

n=0

n

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

n

3.05

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

n=0

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

y

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

y

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

n

6.07

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

See left

5

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

n

7.05

Propagules water dispersed

y=1, n=-1

n

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

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

n

8.02

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

y=1, n=-1

8.03

Well controlled by herbicides

y=-1, n=1

8.04

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

y=1, n=-1

8.05

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

y=-1, n=1

Total score:

-5

Supporting data:

Source

Notes

1.01

no evidence

1.02

no evidence

1.03

no evidence

2.01

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

Distribution: Coastal rainforests from central New South Wales to far north Queensland

2.02

2.03

(1) http://farrer.riv.csu.edu.au/ASGAP/b-ace.html (2) Horticopia A-Z.Horticopia, Inc., Purcellville, VA. ISBN 1-887215-07-7. (3)http://www.brisrain.webcentral.com.au/stages2.html (4)http://ecocrop.fao.org/

(1) "Distribution: Coastal rainforests from central New South Wales to far north Queensland; The tree is hardy in a wide range of soils and is suited for temperate to tropical areas." (2) Hardiness Range: 10A - 11 [Although (2) indicate a tropical only hardiness range, the native distribution show a broad climate suitability] (3)Succesional status: Late Secondary Species (4) at elevations betweensea level and 800 m, The latitudinal range in Australia is 13-36°S. Flame tree thrives on sheltered sites in mountain and river valleys or in coastal lowlands.

2.04

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

Coastal rainforests from central New South Wales to far north Queensland

2.05

(1) Whistler, A.W. (2000) Tropical Oramentals: a Guide. Timber Press, Inc., Portland, Oregon. 542pp. P.89,

"widely cultivated as a deciduous, seasonally flowering tree in warm places, some what more commonly in the subtropicals and warm temperate regions than in the tropics."

3.01

no evidence

3.02

no evidence

3.03

no evidence

3.04

no evidence

3.05

(1) Buist, M.; Yates, C. J.; Ladd, P. G. (2000) Ecological characteristics of Brachychiton populneus (Sterculiaceae) (kurrajong) in relation to the invasion of urban bushland in south-western Australia. Austral Ecology, 2000, Vol.25, No.5, pp.487-496, 35 ref.
(2) http://bodd.cf.ac.uk/index.html

(1) AB: "Brachychiton populneus (Sterculiaceae) (Schott et Endl.) R. Br. (kurrajong) is a small tree that occurs naturally ranging from southern Queensland to Victoria. It has been widely planted as an ornamental tree in south-western Australia. In Kings Park, B. populneus has moved from cultivation to become a weed in the adjoining bushland reserve. " [this is a dubious case because the example involves a simple range extension rather than spreading into a new geographic region] (2) Handling of the seeds caused irritation of the fingers and eyes (Hurst 1942).

4.01

Horticopia A-Z.Horticopia, Inc., Purcellville, VA. ISBN 1-887215-07-7.

Trunk has no thorns

4.02

no evidence

4.03

no evidence

4.04

(1)http://www.perthzoo.wa.gov.au/wildlife_facts_fodder.html (2)http://ww2.zoo.nsw.gov.au/zoo.net/gorilla/info/content/plants.aspx (3)http://216.239.53.104/search?q=cache:ZlVczU3BgekJ:www.rirdc.gov.au/reports/AFT/CSZ-1A.doc+Brachychiton+acerifolius+browse&hl=en&ie=UTF-8

(1)Sometimes harvested for fodder for Giraffes in zoos. (2)Listed as one of the species that gorillas browse on. (3)Brachychiton species are listed as good fodder trees. 'All the Brachychiton species are good fodder trees (Everist 1986), and the kurrajong (b. acerifolius) is one of the best-recognised native browse species.'

4.05

no evidence

4.06

no evidence

4.07

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

"The seeds are surrounded in the capsule by irritant hairs and are best collected using gloves."

4.08

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

(1) B.acerifolius is generally deciduous before flowers are seen in early summer. (2) Attributes and Features

- Low flammability

4.09

(1) http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

Environment: prefers full sun

4.1

(1) http://farrer.riv.csu.edu.au/ASGAP/b-ace.html (2) Horticopia A-Z.Horticopia, Inc., Purcellville, VA. ISBN 1-887215-07-7.

(1) "The tree is hardy in a wide range of soils" (2) Soil Condition Loamy, sandy, clay, acidic, neutral, slightly alkaline, tolerates salt, drought tolerant

4.11

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

"B.acerifolius is a small to medium sized tree which may reach 30-35 metres in height although it is usually much smaller in cultivation in cooler areas"

4.12

no evidence

5.01

terrestrial

5.02

tree; Malvaceae (Sterculiaceae)

5.03

no evidence

5.04

tree

6.01

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

"Conservation Status: Not considered to be at risk in the wild "

6.02

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

"Propagation from seed is relatively easy without any pretreatment. "

6.03

(1)http://www.museums.org.za/bio/plants/malvaceae/brachychiton.htm (2)http://farrer.riv.csu.edu.au/ASGAP/b-pop.html

no evidence (1)Brachychiton populneus x acerifolius is listed as garden origin. (2)B.populneus is commonly cultivated and is hardy in a range of climates and soils. At least three hybrids with B. acerifolius are known and have been brought into cultivation - B. x roseus, B. 'Jerilderie Red' and B. 'Froggatt's Pink'. All have some of the flowering qualities of their famed Illawarra Flame Tree parent plus more persistent, attractive foliage from the Kurrajong parent.'

6.04

no evidence

6.05

http://www.forests.qld.gov.au/qts/treetext.html

Provides food for the pencilled blue and common aeroplane butterflies [appears to be butterfly pollinated]

6.06

no evidence

6.07

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

(1)Flowering may take around 5-8 years from seed

7.01

unlikely, large fruit and seed

7.02

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

"Illawarra flame tree is the most commonly cultivated species due to its spectacular crimson flowers"

7.03

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

leathery seed capsules which contain many corn-like seeds. - relatively large seeds.

7.04

(1) Whistler, A.W. (2000) Tropical Oramentals: a Guide. Timber Press, Inc., Portland, Oregon. 542pp. P.90, (2) http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

(1) p.90 "Fruit of one to five long-stalked follicles 9-12 cm long, (2) leathery seed capsules which contain many corn-like seeds.

7.05

no evidence

7.06

fruit a capsule without fleshy part on diaspores

7.07

no evidence

7.08

no evidence

8.01

http://farrer.riv.csu.edu.au/ASGAP/b-ace.html

The flowers are followed by large, leathery seed capsules which contain many corn-like seeds. [probably not, large fruit and medium sized seeds]

8.02

(1)http://farrer.riv.csu.edu.au/ASGAP/b-ace.html (2)http://www.australiaplants.com/Brachychiton_acerifolius.htm

(1)"Propagation from seed is relatively easy without any pretreatment. " (2)Pour just boiled water over seed and let soak 24 hr [conflicting information]

8.03

no evidence of being controlled

8.04

no evidence

8.05

no evidence


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This page updated 30 September 2005