Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Acacia confusa



Acacia confusa


  • Last modified
  • 20 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Host Plant
  • Preferred Scientific Name
  • Acacia confusa
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Spermatophyta
  •       Subphylum: Angiospermae
  •         Class: Dicotyledonae
  • Summary of Invasiveness
  • A. confusa is invasive in Hawaii (Luken and Thieret, 1996). Bingelli (1999) classed this species as moderately invasive.

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TitleTree habit
Copyright©Li Jiyuan
Tree habit©Li Jiyuan
Fujian Province, China.
CaptionFujian Province, China.
Copyright©Li Jiyuan
Fujian Province, China.
PlantationFujian Province, China.©Li Jiyuan
Copyright©Li Jiyuan
Foliage©Li Jiyuan


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Preferred Scientific Name

  • Acacia confusa Merr.

International Common Names

  • English: acacia petit; Formosan acacia; Formosan koa; mimosa; small Phillipine acacia; Taiwan acacia
  • Chinese: Taiwan xiangshi

Local Common Names

  • Guam: boiffuring; shoshigi; sosigi; sosugi
  • Micronesia, Federated states of: pilampwoia
  • Northern Mariana Islands: serepa; soschghi
  • Palau: ianángi; yanangi

EPPO code

  • ACACU (Acacia confusa)

Trade name

  • Taiwan acacia

Summary of Invasiveness

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A. confusa is invasive in Hawaii (Luken and Thieret, 1996). Bingelli (1999) classed this species as moderately invasive.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Spermatophyta
  •             Subphylum: Angiospermae
  •                 Class: Dicotyledonae
  •                     Order: Fabales
  •                         Family: Fabaceae
  •                             Subfamily: Mimosoideae
  •                                 Genus: Acacia
  •                                     Species: Acacia confusa

Notes on Taxonomy and Nomenclature

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A. confusa is in the tribe Acacieae of the genus Acacia.


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A. confusa is small tree with adult foliage of falcate phyllodes, juvenile and sucker-shoot of bipinnate leaves; trunk up to 1 m thick in very old trees; phyllodes alternate, coriaceous, parallel-curving-veined, 8-10 cm long, narrowed at both ends; flowers yellow, in small globose heads 6-8 mm in diameter; heads 1 or 2 in axil of phyllode; pods few together, linear or somewhat curved, flat or slightly twisted, brown, 5-10 cm long, 1 cm broad or a little more or less, with about eight seeds; seeds compressed, brown (Stone, 1970; PIER, 2002)

Plant Type

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Vegetatively propagated


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A. confusa has a restricted native range, apparently native only to Taiwan and the northern Philippines.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 10 Jan 2020
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Planted Reference Notes




ChinaPresentPresent based on regional distribution.
JapanPresentPresent based on regional distribution.
-Ryukyu IslandsPresentIntroduced
MalaysiaPresentPresent based on regional distribution.
-Peninsular MalaysiaPresentIntroduced

North America

United StatesPresentPresent based on regional distribution.
-HawaiiPresentIntroducedInvasiveFirst reported: c. 1915; Original citation: Luken & Thieret, 1996


Federated States of MicronesiaPresentIntroduced
Northern Mariana IslandsPresentIntroduced

History of Introduction and Spread

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A. confusa was introduced to Hawaii, USA in 1915 and has also been introduced and planted in a number of Asian, Pacific and Indian Ocean countries, and PIER (2002) report that it continues to be actively planted in Micronesia.

Risk of Introduction

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It is possible that the species may become invasive in other areas where it has been introduced. Information on the biology and management of A. confusa is not widely available, but PIER (2002) report that due to its status as a pest in some countries e.g. Hawaii, it should not be introduced to islands where it is not already present.


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A. confusa is a nitrogen fixing species and a pioneer tree on wastelands, adaptable to a wide range of soils.

Habitat List

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Biology and Ecology

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A. confusa reproduces from seeds and from cuttings. Fire can stimulate the germination of large numbers of seeds, and it will also resprout after fire (PIER, 2002). A. confusa is a nitrogen fixing species and a pioneer tree on wastelands, growing rapidly and has great adaptability including shallow and infertile soils, though it prefers acid, free-draining soils. A. confusa prefers a summer or uniform rainfall regime, a mean annual rainfall of 1300 to 3000 mm, and a dry season duration not exceeding 5 months. The mean annual temperature in its native range is 18-26°C, with the mean minimum of the coolest month 14-16°C and the mean maximum of the hottest month 26-29°C, and it will tolerate an absolute minimum temperature of 0°C. It is generally a lowland species but can be found at altitudes up to 800 m.

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
25 6 50 800

Air Temperature

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Parameter Lower limit Upper limit
Absolute minimum temperature (ºC) -8 0
Mean annual temperature (ºC) 18 26
Mean maximum temperature of hottest month (ºC) 26 29
Mean minimum temperature of coldest month (ºC) 14 16


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ParameterLower limitUpper limitDescription
Dry season duration25number of consecutive months with <40 mm rainfall
Mean annual rainfall13003000mm; lower/upper limits

Rainfall Regime

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Soil Tolerances

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Soil drainage

  • free

Soil reaction

  • acid

Soil texture

  • medium

Special soil tolerances

  • infertile
  • shallow

Notes on Natural Enemies

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A number of generalist pests and pathogens have been observed attacking A. confusa, though none are considered to be especially damaging.

Means of Movement and Dispersal

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The species has been introduced outside its native range and it is possible that the species may become invasive in other areas where it has been introduced.

Impact Summary

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Animal/plant collections None
Animal/plant products None
Biodiversity (generally) Negative
Crop production None
Environment (generally) None
Fisheries / aquaculture None
Forestry production None
Human health None
Livestock production None
Native fauna None
Native flora Negative
Rare/protected species None
Tourism None
Trade/international relations None
Transport/travel None

Impact: Biodiversity

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A. confusa reaches a height of 15 m and shades out many other species in Hawaii and it is suspected that the leaves have allelopathic properties because other species do not grow beneath it (PIER, 2002).

Threatened Species

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Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Peucedanum sandwicense (makou)NatureServe; USA ESA listing as threatened speciesHawaiiCompetition - smotheringUS Fish and Wildlife Service (2011)
Tetramolopium filiforme (ridgetop tetramolopium)USA ESA listing as endangered speciesHawaiiCompetition - monopolizing resourcesUS Fish and Wildlife Service (2010)

Risk and Impact Factors

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  • Proved invasive outside its native range
  • Highly adaptable to different environments
  • Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
  • Highly mobile locally
  • Has high reproductive potential
Impact outcomes
  • Damaged ecosystem services
  • Ecosystem change/ habitat alteration
  • Reduced native biodiversity
Impact mechanisms
  • Competition - monopolizing resources
  • Competition - smothering
  • Produces spines, thorns or burrs


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It is widely cultivated for coastal shelterbelt forests, soil and water conservation, fuelwood stands and for ornamental purposes. It also shows high potential for the pulp industry. It has a range of wood and non-wood end uses including amongst others, fuelwood, industrial and non-industrial domestic woodware, oils, bark products, honey and tannins.

Uses List

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  • Erosion control or dune stabilization
  • Shade and shelter
  • Soil improvement
  • Windbreak


  • Fuelwood


  • Ornamental

Human food and beverage

  • Honey/honey flora


  • Carved material
  • Dye/tanning
  • Essential oils
  • Fibre
  • Miscellaneous materials
  • Wood/timber

Wood Products

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  • Short-fibre pulp

Railway sleepers

Vehicle bodies


  • Industrial and domestic woodware
  • Tool handles

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Control of A. confusa is possible if saplings are treated with herbicides including 2,4-D and triclopyr, with sensitivity in varying degrees to cut-surface applications of 2,4-D, dicamba, glyphosate, picloram and triclopyr and to basal bark application of triclopyr in oil (PIER, 2002).


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Chang TT, 1995. Decline of nine tree species associated with brown root rot caused by Phellinus noxius in Taiwan. Plant Disease, 79(9):962-965

Chen DZ, 1988. China Flora. Beijing, China: Science Press, Vol. 39, 24

Dou TL, 1983. Afforestation of light contained Acacia confusa seedling and its economic benefits. Sichuan Forest Science and Technology, 4(3):46-52

Gardner DE, 1980. Acacia koa seedling wilt caused by Fusarium oxysporum f. sp. kop, f. sp. nov. Phytopathology, 70(7):594-597

Gui SZ, Shi MF, Fang CQ, 1987. Incident and control of Acacia confusa rust disease. Plant protection, Beijing. Vol. 4, 39-40

Hirane S, 1938. Studies on the parasitism of the rust of Acacia confusa Merrill, Maravalia hyalospora (Saw.) Diet. II. Effects of the juice of phyllodes on the germination and germ-tube development of urediospores. Trans. nat. hist. Soc. Formosa 28; 29 1938; 1939 (421-30); (13-21)

Huag PQ, Wang LX, 1983. Silviculture of Major Plantation Trees in Guangdong Province. Guangdong, China: Guangdong Forest Science and Technology Press, pp. 108-111

Huang TC; OHashi H, 1995. In Huang TC (ed.) Flora of Taiwan. Vol 3. Natural Science Council. Taipei, Taiwan: Roc. 2nd ed

Li HL, 1963. Woody flora of Taiwan. 1963. pp. X + 974. 123 refs. Livingston Publishing Company, Narberth, Pa

Liang ZX, Chen SP, Deng Y, 1989. Utilization and improvement of vegetation in the hilly coast region of Guangdong. Acta Botanica Austro Sinica, No. 4, 259-265; 3 ref

Lin HS, 1986. Comparative experiment of afforestation with Acacia confusa, A. mangium and A. auriculiformis. Guangdong Forest Science And Technology, 4:22-25

Pan ZG, Yang MQ, 1988. Preliminary results of provenance trials with 5 tropical Acacia tree species at age of 3 years old. Forest Research, 5:553-557

Tab XS, Wang GS, 1984. Root rot: A new disease of Acacia confusa. Hainan Reclamation Bureau. Forest Science and Technology, No. 9, 29

US Fish and Wildlife Service, 2010. Tetramolopium filiforme (no common name). 5-Year Review: Summary and Evaluation. In: Tetramolopium filiforme (no common name). 5-Year Review: Summary and Evaluation : US Fish and Wildlife Service.11 pp.

US Fish and Wildlife Service, 2011. Endangered and Threatened Wildlife and Plants; Listing 23 Species on Oahu as Endangered and Designating Critical Habitat for 124 Species. In: Federal Register , 76(148) : US Fish and Wildlife Service.46362-46593.

Wang HZ, 1985. Seed collection and nursery practice of the main Chinese tropical and subtropical trees. China: People's Publishing House, pp. 261

Wang KC, 1972. Investigation on the species of root-knot nematodes infesting trees in nurseries. Technical Bulletin, Experimental Forest of National Taiwan University, No. 102, 24 pp.; 8 ref

Watanabe H, Abe K, Hao FQ, 1988. Shade trees for perennial crops in Hainan, China. Japanese Journal of Tropical Agriculture, 32(4):242-244; 3 ref

Wu ZY, 1984. Index Florae Yunnanensis. Yunnan, China: People's Publishing House

Wu ZY, 1984. Index Florae Yunnanensis. Yunnan, China: The People's Publishing House

Xiao GG(Chief Editor), 1991. Forest insects of China. Beijing, China; China Forestry Publishing House, Ed. 2:vi + 1362 pp

Xu YQ, 1976. Major economic tree species in south China. Beijing, China: Agriculture Press

Xu YQ, 1990. Forestry in Guangdong Province. Guangdong, China: Guangdong Science & Technology Press

Yang MQ, 1990. Growth characteristics and adaptability of major tropical Acacia species in south China. Forest Research, 2:155-161

Ying SL, Chien CY, Davidson RW, 1976. Root rot of Acacia confusa. Quarterly Journal of Chinese Forestry, 9(1):17-21; 1 pl.; 3 ref

Zhang HB, 1993. Forestry in Fujian Province. Beijing, China: China Forestry Publishing House, pp. 60-64

Zhang XS, 1982. Survey of afforestation of Acacia confusa mixed with Pinus massoniana in aerial sowing. Guangdong Forest Science And Technology Communications, 4: 22-25

Zheng WJ, 1978. Silvicultural techniques of major tree species in China. Beijing, China: Chinese Agriculture Publishing House, Vol. 2

Zheng WJ, 1983. Sylva Sinica. Vol. 1. [Zhongguo shumu zhi. Diyi juan.]. Beijing, China: Chinese Forestry Publishing House (Centralized Book No. 16046.1069)

Zhong XR, 1981. An windfirm tree species: Acacia confusa. China Forestry, 11, 35

Zhou XM, Li QM, 1983. Seedling growth of Acacia confusa, A. mangium and A. auriculiformis. Guangdong Forest Science and Technology Communication, 4, 18-19

Distribution References

CABI, Undated. Compendium record. Wallingford, UK: CABI

CABI, Undated a. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI

CABI, Undated b. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI

PIER, 2002. Pacific Islands Ecosystems at Risk., Honolulu, USA: HEAR, University of Hawaii.

Links to Websites

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GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway source for updated system data added to species habitat list.
Global register of Introduced and Invasive species (GRIIS) source for updated system data added to species habitat list.

Distribution Maps

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