Pacific Island Ecosystems at Risk (PIER)


Acacia melanoxylon


RISK ASSESSMENT RESULTS: High risk, score: 12


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

Acacia melanoxylon; Australian blackwood

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

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

y

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

y

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

y

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

y

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

y

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

2

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

7.06

Propagules bird dispersed

y=1, n=-1

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

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

n

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

n

Total score:

12

Supporting data:

Source

Notes

1.01

No evidence.

1.02

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

"It has become a weed species in South Africa where it regenerates in gaps in indigenous forests and along stream banks."

1.03

No evidence.

2.01

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

A. melanoxylon has an extensive distribution through the tablelands and coastal escarpments of southeast Queensland, New South Wales and Victoria to the Mount Lofty Ranges in South Australia and to southern Tasmania.

2.02

2.03

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

(1) A. melanoxylon plantings in New Zealand withstand severe frosts down to about -7ºC (Franklin, 1987). Below this temperature trees may be killed back to ground level but many recover by coppicing.

(2)Altitude range: 0 - 1200 m

2.04

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

A. melanoxylon has an extensive distribution through the tablelands and coastal escarpments of southeast Queensland, New South Wales and Victoria to the Mount Lofty Ranges in South Australia and to southern Tasmania.

2.05

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

"As an exotic A. melanoxylon has been most extensively grown in India and South Africa and shows promise in New Zealand and several countries in South America (Gleason, 1986; Nicholas and Gifford, 1995). It is also common in the hill country (1400-2000 m) of Sri Lanka (Midgley and Vivekanandan, 1987) and in the high country (>1200 m) of East Africa (e.g. in Kenya and Tanzania) (Streets, 1962). It is regarded as good or promising in parts of China (Wang et al., 1994)."

3.01

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

"It has become a weed species in South Africa where it regenerates in gaps in indigenous forests and along stream banks."

3.02

No evidence.

3.03

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

"It is prized for its decorative wood which is used in furniture and veneer. It is also useful for shade and shelter, and ornamental plantings."

3.04

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

"It has become a weed species in South Africa where it regenerates in gaps in indigenous forests and along stream banks."

3.05

Weed Control Manual 2000. Meister Publishing Co., Salem, MA.

Acacia rigidula, Acacia tortuosaand Acacia farnesiana are listed under weeds of pastures and rangeland. Tricopyr is the suggested herbicide for their control.

4.01

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

"The branchlets are angular with conspicuous ribs; young branchlets are pubescent to hoary, becoming glabrous. "

4.02

González, L.; Souto, X. C.; Reigosa, M. J. (1995) Allelopathic effects of Acacia melanoxylon R. Br. phyllodes during their decomposition. Forest Ecology and Management, 1995, Vol.77, No.1/3, pp.53-63, 24 ref.

AB: The development of phytotoxicity of phyllodes from Acacia melanoxylon was studied during litter-bag decomposition in four different plots near Santiago de Compostela, NW Spain. The four sites were an oakwood (Quercus robur ), and plantations of Eucalyptus globulus , Pinus radiata and Acacia melanoxylon , on ranker soils over granite with mica. Recently fallen foliage from Q. robur and phyllodes from A. melanoxylon were buried in litter bags on the four sites in January 1990. The toxicity of the extracts was estimated by measuring the effects on the germination and growth of Lactuca sativa var. Great Lakes seeds, after 1, 7, 15, 30, 180 and 365 days of decomposition in each soil. The toxicity of various leachates (e.g., phenolic compounds) is shown and the influence of different soil microbiological conditions on the liberation of phytotoxins is discussed. Results indicate that residues from A. melanoxylon produce a strong inhibitory effect at the beginning of litter decomposition. This toxicity appeared

4.03

No evidence.

4.04

(1) CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.
(2) McArthur, C.; Goodwin, A.; Turner, S. (2000) Preferences, selection and damage to seedlings under changing availability by two marsupial herbivores. Forest Ecology and Management, 2000, Vol.139, No.1/3, pp.157-173, 52 ref.

(1)"A. melanoxylon seedlings are extremely palatable to native marsupials, deer, domestic livestock and rabbits."
(2) AB: "Preferences for and damage to seedlings used in commercial forestry in Tasmania, Australia, by brushtail possums (Trichosurus vulpecula ) and Tasmanian pademelons (Thylogale billardierii ) were measured in paired-species feeding trials with captive animals. Both possums and pademelons consistently ate foliage more than stems for all seedling species examined. Possums showed significant interspecific foliage preferences more often than pademelons and they often had opposite preferences to pademelons. For possums, Eucalyptus nitens was one of the most preferred species, whereas for pademelons, Acacia melanoxylon and Pinus radiata were preferred. "

4.05

(1) CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.
(2) McArthur, C.; Goodwin, A.; Turner, S. (2000) Preferences, selection and damage to seedlings under changing availability by two marsupial herbivores. Forest Ecology and Management, 2000, Vol.139, No.1/3, pp.157-173, 52 ref.

(1)"A. melanoxylon seedlings are extremely palatable to native marsupials, deer, domestic livestock and rabbits."
(2) AB: "Preferences for and damage to seedlings used in commercial forestry in Tasmania, Australia, by brushtail possums (Trichosurus vulpecula ) and Tasmanian pademelons (Thylogale billardierii ) were measured in paired-species feeding trials with captive animals. Both possums and pademelons consistently ate foliage more than stems for all seedling species examined. Possums showed significant interspecific foliage preferences more often than pademelons and they often had opposite preferences to pademelons. For possums, Eucalyptus nitens was one of the most preferred species, whereas for pademelons, Acacia melanoxylon and Pinus radiata were preferred. "

4.06

(1) CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.
(2) McArthur, C.; Goodwin, A.; Turner, S. (2000) Preferences, selection and damage to seedlings under changing availability by two marsupial herbivores. Forest Ecology and Management, 2000, Vol.139, No.1/3, pp.157-173, 52 ref.

Allen (1992) provides a summary of pests and diseases of A. melanoxylon. In natural stands, blackwood is attacked by a wide range of insects but none is of economic consequence (Jennings, 1991).
Jennings SM, 1991. Blackwood. Technical-Bulletin -Native-Forest-Silviculture,-Forestry-Commission,-Tasmania. 1991, No. 10, 28 pp.; 17 ref.

4.07

Hausen, B. M.; Bruhn, G.; Tilsley, D. A. (1990) Contact allergy to Australian blackwood (Acacia melanoxylon R.Br.): isolation and identification of new hydroxyflavan sensitizers. Contact Dermatitis, 1990, Vol.23, No.1, pp.33-39, 25 ref.

UNCOMMON: AB: Previous investigations had isolated two responsible, although weak, quinones present in A. melanoxylon heartwood. A re-examination of wood samples, collected in Tasmania and tested in Hamburg, Germany, resulted in the identification of 4 hydroxyflavans. Three of these proved to be allergens. Melacacidin, the main constituent of these flavan derivatives in the heartwood, was isolated and its sensitizing capacity determined by patch testing in 1983, 1985 and 1989. It showed a moderate sensitizing power. Melacacidin occurs abundantly in 125 Australian and 3 African Acacia species, and Australian blackwood is cultivated in E. and S. Africa and has been introduced into Argentina, Chile, Sri Lanka and India.

4.08

 

No evidence.

4.09

Geldenhuys, C. J. (1996) The Blackwood Group System: its relevance for sustainable forest management in the southern Cape. South African Forestry Journal, 1996, No.177, pp.7-21, 26 ref.

AB: "It has the characteristics of an aggressive invader plant, but it does not aggressively invade closed, evergreen forest. In closed forest its population diameter distribution is bell-shaped, a curve typical of pioneering populations in maturing vegetation. ", "It is concluded that the ecological characteristics and requirements of the shade-intolerant blackwood should be considered in relation to the ecological processes of disturbance and recovery of the forest to reconcile its production in the forest as a timber tree with control of its invasion potential. "

4.1

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

- Soil texture: light; medium; heavy
- Soil drainage: free; seasonally waterlogged
- Soil reaction: acid
- Special soil tolerances: saline
- Soil types: alluvial soils; clay soils; podzols; sandy soils

4.11

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

"A. melanoxylon is often 10-20 m tall and 0.5 m diameter, but varies from a small shrub to one of the largest acacias in Australia, attaining heights up to 40 m and diameters of 1-1.5 m on lowlands in northwestern Tasmania, and in southern Victoria."

4.12

No evidence.

5.01

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

"A. melanoxylon is often 10-20 m tall and 0.5 m diameter, but varies from a small shrub to one of the largest acacias in Australia, attaining heights up to 40 m and diameters of 1-1.5 m on lowlands in northwestern Tasmania, and in southern Victoria."

5.02

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

"A. melanoxylon is often 10-20 m tall and 0.5 m diameter, but varies from a small shrub to one of the largest acacias in Australia, attaining heights up to 40 m and diameters of 1-1.5 m on lowlands in northwestern Tasmania, and in southern Victoria."

5.03

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

"A. melanoxylon is a long-lived, nitrogen-fixing species that may attain up to 1.5 m in diameter and 40 m in height."

5.04

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

"A. melanoxylon is often 10-20 m tall and 0.5 m diameter, but varies from a small shrub to one of the largest acacias in Australia, attaining heights up to 40 m and diameters of 1-1.5 m on lowlands in northwestern Tasmania, and in southern Victoria."

6.01

"Ground-stored seed from natural seed fall can remain viable for more than 50 years (Searle, 1996). There are 64,000 viable seeds/kg with an average germination rate of 75% (Doran and Turnbull, 1997). Optimum temperature for germination of blackwood seed is 25°C but germination occurs throughout the range of 15-35°C (Bell and Bellairs, 1992)."

"Ground-stored seed from natural seed fall can remain viable for more than 50 years (Searle, 1996). There are 64,000 viable seeds/kg with an average germination rate of 75% (Doran and Turnbull, 1997). Optimum temperature for germination of blackwood seed is 25°C but germination occurs throughout the range of 15-35°C (Bell and Bellairs, 1992)."

6.02

"Ground-stored seed from natural seed fall can remain viable for more than 50 years (Searle, 1996). There are 64,000 viable seeds/kg with an average germination rate of 75% (Doran and Turnbull, 1997). Optimum temperature for germination of blackwood seed is 25°C but germination occurs throughout the range of 15-35°C (Bell and Bellairs, 1992)."

"Ground-stored seed from natural seed fall can remain viable for more than 50 years (Searle, 1996). There are 64,000 viable seeds/kg with an average germination rate of 75% (Doran and Turnbull, 1997). Optimum temperature for germination of blackwood seed is 25°C but germination occurs throughout the range of 15-35°C (Bell and Bellairs, 1992)."

6.03

Don't know

6.04

Muona, O.; Moran, G. F.; Bell, J. C. (1991) Hierarchical patterns of correlated mating in Acacia melanoxylon. Genetics, 1991, Vol.127, No.3, pp.619-626, 27 ref.

AB: Isoenzyme markers were used to test the hypothesis that all seeds within a pod are full sibs, in 2 populations of A. melanoxylon. The proportions of fruit pods with multiple paternity detected in the 2 populations were 0.08 and 0.15, while the proportions of full sib pairs within pods estimated by the sibling pair method were 1 and 0.63. Comparison of the diploid paternal genotypes of pods of single paternity showed that the probability of a common pollen source for a pair of pods was high within globular clusters (0.35) or within inflorescences (0.46) but declined to 0.10 or 0.25 within the tree at random.
[ Decreased single paternity when flowers are further away suggests selfing.]

6.05

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

"The inflorescence consists of 3-5 relatively large globular heads carried on short axillary racemes, 2.5-5 cm long. Each head consists of 30-50 flowers which are whitish to very pale yellow. " [typical mimosoid inflorescent, probably wind pollinated.]

6.06

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

"In trials in southeastern Queensland two provenances, one tropical and the other subtropical, coppiced best when cut at 1 m and both displayed abundant root suckering (Ryan and Bell, 1989)."

6.07

CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International. (Descriptors: disadvantages)

"A. melanoxylon may flower from as early as 2 years (Ryan and Bell, 1989)." Ryan PA, Bell RE, Boland DJ, 1989. Growth, coppicing and flowering of Australian tree species in southeast Queensland, Australia. Trees for the tropics. Growing Australian multipurpose trees and shrubs in Developing Countries. ACIAR-Monograph. 1989, No. 10, 49-68; at end of book; refs.

7.01

No evidence.

7.02

Samraj, P.; Chinnamani, S. (1981) The Australian blackwood acacia. Indian Farming, 1981, Vol.30, No.11, pp.31-33

AB: An account of the silviculture and uses of Tasmanian blackwood [Acacia melanoxylon]. The species is grown in the hills of the Nilgiris and Pulneys (above alt. 1500 m). It can also be grown near centres of livestock farming where the land is unsuitable for intensive cultivation of grasses and legumes, and planted as field boundaries, shelterbelts and ornamental or shade trees. The leaves are used as livestock fodder, twigs as fuelwood, and the wood for pulp, cabinet making, agricultural implements and construction timber.

7.03

No evidence.

7.04

No evidence.

7.05

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

regenerates along stream banks

7.06

Midgley, J. J.; Bond, W. J.1990. Knysna fynbos 'islands': origins and conservation. South African Forestry Journal, , No.153, pp.18-21

Alien species are found on virtually all the 'islands'. Some are planted (e.g. Pinus spp.) and some aliens have presumably been dispersed by wind (Hakea sericea, and Pinus spp.) or by birds (Acacia melanoxylon ). It is recommended that these non-indigenous species should be cleared and the 'islands' conserved as fynbos.

7.07

No evidence.

7.08

possibly, hard seed coat

8.01

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

"There are 64,000 viable seeds/kg with an average germination rate of 75% (Doran and Turnbull, 1997). "

8.02

(1) CAB International, 2000. Forestry Compendium Global Module. Wallingford, UK: CAB International.
(2) Wilkinson, G. R.; Jennings, S. M. (1994) Regeneration of blackwood from ground-stored seed in the Arthur Forests, north-western Tasmania. Tasforests, 1994, Vol.6, pp.69-78, 18 ref.

(1) "Ground-stored seed from natural seed fall can remain viable for more than 50 years (Searle, 1996). There are 64,000 viable seeds/kg with an average germination rate of 75% (Doran and Turnbull, 1997). Optimum temperature for germination of blackwood seed is 25°C but germination occurs throughout the range of 15-35°C (Bell and Bellairs, 1992)."
(2) AB: The total quantity of blackwood (Acacia melanoxylon ) seeds within a soil profile in the North Arthur Forests of Tasmania was greater than 20 000 per m2. Viable seeds were located to a depth of at least 100 cm, with nearly half occurring within the upper 10 cm horizon of the soil profile. Results from experimental treatments indicated that high intensity burning destroyed 67% of the viable seed in the top 7.5 cm of the soil profile and stimulated the germination of more than 95% of the remaining seed. In contrast, soil disturbance resulted in the germination of up to 21% of the seed, with the remainder being retained as a reservoir for future germinations.

8.03

(1) Vanner, A. L. (1994) Tolerance of nursery seedlings of forest tree species to post-emergence herbicides. Proceedings of the forty seventh New Zealand plant protection conference, Waitangi, New Zealand, 9-11 August 1994., 1994, pp.117-120, 1 ref. (2) Vanner, A. L. (1991) Tolerance of several species of tree seedlings to oxyfluorfen. Proceedings of the forty-fourth New Zealand Weed and Pest Control Conference., 1991, pp.17-20, 2 ref.

(1) AB: In eleven trials at two nursery sites near Rotorua during 1991-93, the tolerance of Pinus radiata, Acacia melanoxylon, Cupressus macrocarpa, C. lusitanica and Eucalyptus fastigata seedlings to post-emergence applications of the herbicides clopyralid, methabenzthiazuron and terbuthylazine was evaluated. Seedling tolerance was assessed by comparing height growth and survival with that of seedlings treated with current methods of post-emergence weed control (either herbicides or hand weeding). None of the herbicides significantly affected growth of any tree species. AB: In eleven trials at two nursery sites near Rotorua during 1991-93, the tolerance of Pinus radiata, Acacia melanoxylon, Cupressus macrocarpa, C. lusitanica and Eucalyptus fastigata seedlings to post-emergence applications of the herbicides clopyralid, methabenzthiazuron and terbuthylazine was evaluated. Seedling tolerance was assessed by comparing height growth and survival with that of seedlings treated with current methods of post-eme

8.04

(1)Hill, R. S. (1982) Rainforest fire in western Tasmania. Australian Journal of Botany, 1982, Vol.30, pp.583-589, 9 ref. (2) Chesterfield, E. A.; Taylor, S. J.; Molnar, C. D. (1991) Recovery after wildfire: warm temperate rainforest at Jones Creek, East Gippsland, Victoria. Australian Forestry, 1991, Vol.54, No.3, pp.157-173, 22 ref.

(1) AB: A humus/surface litter fire at Zeehan, Tasmania in 1981 was species-specific, affecting Nothofagus cunninghamii and Eucryphia lucida in particular. The trees which survived were growing on humus too shallow to sustain the fire. The survival of some trees of all the major species in unburnt areas within the fire boundary may be important in regeneration by providing a nearby source of seed. Three months after the fire, seedlings from the fire-stimulated germination of humus-stored Acacia melanoxylon seeds were abundant, but the majority died within the following 6 months. (2) AB: Approximately 80 ha of warm temperate rain forest in far East Gippsland, Australia, was severely burnt in February 1983. The fire (the course of which is briefly described) provided an opportunity to investigate the response of warm temperate rain forest to burning, and to assess the extent to which fire may have influenced the past development of the community. Floristic data were available from before the fire. After i

8.05

Tim Tunison (1991) Element Stewardship Abstract for Acacia melanoxylon, Blackwood Acacia. THE NATURE CONSERVANCY. 1815 North Lynn Street, Arlington, Virginia 22209 (703) 841 5300 available at <http://tncweeds.ucdavis.edu/esadocs/documnts/acacmel.html>

"In Hawaii, invasive in some areas; spreading vegetatively in pine plantations in Waikamoi Preserve, and has begun to escape from the plantations into adjacent drainages."


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