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

Eucalyptus crebra (ironbark, narrow leaved ironbark)

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

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

y

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

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

4.09

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

y=1, n=0

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

4

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

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

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

n

8.03

Well controlled by herbicides

y=-1, n=1

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:

-1

Source

Notes

1.01

No evidence

1.02

"regenerating within plantations" in Hawaii

Wagner,W. L., D. R. Herbst & S. H. Sohmer. 1990. Manual of flowering plants of Hawaii.University of Hawaii at Press. Honolulu.

1.03

No evidence

2.01

Native to Australia - 'E. crebra is widely distributed in eastern Australia (New South Wales and Queensland), occurring mainly in sub-humid climates but with extension into semi-arid and humid climates.'

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

2.02

2.03

(1)Altitude range: 0 - 1400 m Approximate limits north to south: 15°S to 35°S [plantings have survived in this range] (2)USDA Zone 9, native range: found only on the Eyre Peninsula (3)550-2000 mm rainfall. (4)Eucalyptus crebra is most frequent on the lower altitudes.[natural habitat in Australia] (5)Frost resistant [information creates a conflicting picture of environmental range] (6)Widespread in open forests and woodlands throughout SE Queensland

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.australiaplants.com/Eucalyptus_crebra.htm (3)http://www.dpi.qld.gov.au/hardwoodsqld/7706.html (4)http://lamington.nrsm.uq.edu.au/docs/Plant/euc.htm (5)http://www.molestationnursery.com/plantdb/complete.asp (6)Stanley and Ross. 1983. Flora of South-eastern Queensland Vol. 1. Queensland Dept of Prmary Industries, Brisbane

2.04

Naturalized in Hawaii.

Wagner,W. L., D. R. Herbst & S. H. Sohmer. 1990. Manual of flowering plants of Hawaii.University of Hawaii at Press. Honolulu.

2.05

(1)Introduced to several countries. (2)New Zealand

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (2)http://www.nzseeds.co.nz/seed_list/Eucalyptus_crebra.html

3.01

"regenerating within plantations" in Hawaii

Wagner,W. L., D. R. Herbst & S. H. Sohmer. 1990. Manual of flowering plants of Hawaii.University of Hawaii at Press. Honolulu.

3.02

No evidence

3.03

No evidence

3.04

No evidence

3.05

Several Eucalyptus species are principal weeds in Australia.

Holm et al. Geographic Atlas of World Weeds

4.01

No evidence

Wagner,W. L., D. R. Herbst & S. H. Sohmer. 1990. Manual of flowering plants of Hawaii.University of Hawaii at Press. Honolulu.

4.02

No evidence

4.03

No evidence

4.04

The frequent fires of the Aborigines and the plentiful rat-kangaroos that eat young trees stopped almost all regrowth. [refers to E. crebra]

http://pilliga.org/forest/SAFEGUARDS.html

4.05

No evidence

4.06

Two fungi are listed to be associated with E. crebra. Erysiphe cichoracearum and Sphaerotheca alchemillae. No evidence that the above 2 species are recognized pests.

http://nt.ars-grin.gov/fungaldatabases/all/FindRecOneFungusFrame.cfm

4.07

No evidence

4.08

[a single-trunked tree, but Eucalyptus leaves are resinous which could make them unusually flamable]

4.09

culture: sun, Does well in shaded areas

http://www.australiaplants.com/Eucalyptus_crebra.htm

4.1

(1) '...and adaptable to a wide range of soils.' (2)gravels, loams, sandy loams, clays, acid pH

(1)CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.(2)http://www.australiaplants.com/Eucalyptus_crebra.htm

4.11

Probably not- not a vine.

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

4.12

No evidence

5.01

Eucalyptus crebra is a small to medium-sized tree, 15-25 m tall and with a dbh up to 1 m. Myrtaceae

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

5.02

5.03

5.04

No evidence

6.01

Forms hybrids with E. melamophloia and E. populnea in native range.

Eldridge. K. et al. 1993. Eucalypt domestication and breeding. Claredon press Oxford.

6.02

'Seed germinates easily with normal methods.'

http://www.australiaplants.com/Eucalyptus_crebra.htm

6.03

'E. crebra and E. melanophloia hybrids were reproducing less fit than the pure species. However E. crebra X E. populnea hybrids studied by Drake were reproductively successful and well adapted to the ecotone between these two species.'

Eldridge. K. et al. 1993. Eucalypt domestication and breeding. Claredon press Oxford.

6.04

No evidence

6.05

Probably not -(1) species with larger flowers among eucalypts (more than 2 cm in diameter) are pollinated by birds but those with small flowers have no apparent adaptation to particular vectors and are visited by a great variety of insects. (2) In E. crebra umbels 3 to 7 flowered and buds 4 to 6 X 3 to 3.5 mm. [small flowers] (3)major source of pollen for bees

(1)Eldridge, K. et al. 1993. Eucalypt domestication and breeding. Clarendon press. Oxford. (2) Penfold, A.R. and Willis J.L. 1961. The Eucalypts. Interscience publishers. (3)Stanley and Ross. 1983. Flora of South-eastern Queensland Vol. 1. Queensland Dept of Prmary Industries, Brisbane

6.06

No evidence

6.07

(1)Trees between twenty to forty years of age produce the most seeds [reference for general Eucalypts] (2)After a caspule is formed, ripening of the capsule takes at least a year (3)Slow growth. [given this information, 4 years is entered as an absolute minimum. Probably it is longer.

(1)http://wwwlibrary.csustan.edu/bsantos/section2.htm#SEEDS (2)http://farrer.riv.csu.edu.au/ASGAP/eucalypt.html (3)http://www.dpi.qld.gov.au/hardwoodsqld/7706.html

7.01

Probably not - no evidence that the seeds have any means of attachment.

7.02

Probably yes- it is a forestry species.

7.03

No products

7.04

'In the genus Eucalyptus fruit is a capsule enclosed by woody hypanthium, loculicidally dehiscent at top, with numerous seeds varied in color and shape.' - No evidence that the seeds have special adaptation for wind dispersal - most probably disperse by wind/gravity.

Wagner,W. L., D. R. Herbst & S. H. Sohmer. 1990. Manual of flowering plants of Hawaii.University of Hawaii at Press. Honolulu.

7.05

7.06

7.07

Probably not - no evidence that the seeds have any means of attachment.

7.08

Capsules not consumed

8.01

Probably yes - 'the genus Eucalyptus produces numerous seeds. In E. crebra the fruit is ovoid, 4-7 mm long and 4-6 mm wide, valves 3 to 4.'

Wagner,W. L., D. R. Herbst & S. H. Sohmer. 1990. Manual of flowering plants of Hawaii.University of Hawaii at Press. Honolulu.

8.02

(1)Seed germinates easily with normal methods [implies lack of dormancy] (2)Cold stratify for 28 days, water soak overnight spread seed between layers of wet absorbent paper seal in a plastic bag with plenty of air space.

(1)http://www.australiaplants.com/Eucalyptus_crebra.htm (2)http://www.nzseeds.co.nz/seed_list/Eucalyptus_crebra.html

8.03

No evidence that the species is being controlled for.

8.04

Suited for coppicing

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.

8.05

Don’t know.