Pacific Island Ecosystems at Risk (PIER)

  [   PIER species lists  ]   [   PIER home  ]

Acacia confusa
Merr., Fabaceae
Click on an image for links to BIGGER PICTURES


Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 10 (Go to the risk assessment)

Common name(s): [more details]

Carolinian: serepa, soschghi

Chamorro: boiffuring, boiffuring, shoshigi, sosigi, sosugi

Chinese: tai wan xiang si

English: Formosa acacia, Formosan koa

Japanese: sosijyu

Palauan: ianángi, yanangi

Pohnpeian: pilampwoia

Habit:  tree

Description:  "Small tree; adult foliage of falcate phyllodes, juvenile and sucker-shoot foliage 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 8 seeds; seeds compressed, brown" (Stone, 1970; p. 295).

Description from Flora of China online.

Habitat/ecology:  "Mesic to humid areas in both pastures and forests.  Forms monotypic stands in pastures and disturbed sites in forests; eliminates ground cover"  (Motooka et al., 2003).  Grows well in both dry and mesic habitats. Will often resprout after fire. In Hawai‘i, it was planted for windbreaks on Maui and has since formed monotypic stands at lower elevations and continues to spread up to 1000 m (Randy Bartlett, communication on Aliens list server).

Propagation:  Seeds present in the ground can germinate profusely after fire. Spread through forestry and ornamental plantings. Can be reproduced from cuttings.

Native range:  A native of the Northern Philippines, naturalized extensively in Taiwan, Okinawa, and Saipan. In Hawai'i, "widely cultivated and now naturalized in dry to mesic, disturbed areas, 3-915 m" (Wagner et al., 1999; p. 641).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Aguijan (Agiguan, Aguihan) Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Aguijan (Agiguan, Aguihan) Island   Bishop Museum (Honolulu) (1952) (voucher ID: BISH 152469)
Taxon name on voucher: Acacia confusa Merr.
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Aguijan (Agiguan, Aguihan) Island   Bishop Museum (Honolulu) (1952) (voucher ID: BISH 152470)
Taxon name on voucher: Acacia confusa Merr.
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Rota Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Rota Island introduced
invasive
cultivated
Space, James C./Waterhouse, Barbara/Denslow, Julie S./Nelson, Duane (2000) (p. 6)
Some naturalization noted.
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island introduced
invasive
Meyer, Jean-Yves (2000) (p. 101)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island introduced
cultivated
Space, James C./Falanruw, Marjorie (1999) (p. Field notes.)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island   Bishop Museum (Honolulu) (1946) (voucher ID: BISH 152468)
Taxon name on voucher: Acacia confusa Merr.
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island   Bishop Museum (Honolulu) (1946) (voucher ID: BISH 567924)
Taxon name on voucher: Acacia confusa Merr.
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Saipan Island   Bishop Museum (Honolulu) (1966) (voucher ID: BISH 659659)
Taxon name on voucher: Acacia confusa Merr.
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Sarigan Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Sarigan Island introduced
cultivated
Fosberg, F. R./Falanruw, M. V. C./Sachet, M.-H. (1975) (p. 26)
Voucher cited: Fosberg 31427 (US)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Sarigan Island   Bishop Museum (Honolulu) (1967) (voucher ID: BISH 401441)
Taxon name on voucher: Acacia confusa Merr.
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Tinian Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Commonwealth of the Northern Mariana Islands (US)
Northern Mariana Islands
Tinian Island introduced
invasive
Meyer, Jean-Yves (2000) (p. 101)
Federated States of Micronesia
Chuuk Islands
Tol Island   Wagner, W. L./ Herbst, D. R./Weitzman, A./Lorence, D.H. (2013)
Federated States of Micronesia
Chuuk Islands
Weno (Moen) Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Federated States of Micronesia
Chuuk Islands
Weno (Moen) Island   Bishop Museum (Honolulu) (1935) (voucher ID: BISH 152473)
Taxon name on voucher: Acacia confusa Merr.
Federated States of Micronesia
Chuuk Islands
Weno (Moen) Island   Bishop Museum (Honolulu) (1980) (voucher ID: BISH 659660)
Taxon name on voucher: Acacia confusa Merr.
Federated States of Micronesia
Chuuk Islands
Weno (Moen) Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1965) (voucher ID: PTBG 23985)
Taxon name on voucher: Acacia confusa
Federated States of Micronesia
Pohnpei Islands
Pohnpei Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Federated States of Micronesia
Pohnpei Islands
Pohnpei Island introduced
Meyer, Jean-Yves (2000) (p. 90)
"Potential invader"
Federated States of Micronesia
Pohnpei Islands
Pohnpei Island introduced
Glassman, S. F. (1952) (p. 74)
Federated States of Micronesia
Pohnpei Islands
Pohnpei Island introduced
cultivated
Herrera, Katherine/Lorence, David H./Flynn, Timothy/Balick, Michael J. (2010) (p. 88)
Federated States of Micronesia
Yap Islands
Yap (Waqab) Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Federated States of Micronesia
Yap Islands
Yap (Waqab) Island introduced
Meyer, Jean-Yves (2000) (p. 90)
"Potential invader"
Guam
Guam Island
Guam Island introduced
cultivated
Stone, Benjamin C. (1970) (p. 295)
Guam
Guam Island
Guam Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Guam
Guam Island
Guam Island   Bishop Museum (Honolulu) (1965) (voucher ID: BISH 659661)
Taxon name on voucher: Acacia confusa Merr.
Guam
Guam Island
Guam Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1988) (voucher ID: PTBG 22715)
Taxon name on voucher: Acacia confusa
Guam
Guam Island
Guam Island   National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1965) (voucher ID: PTBG 23144)
Taxon name on voucher: Acacia confusa
State of Hawaii
Hawaiian Islands
Hawai‘i (Big) Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
State of Hawaii
Hawaiian Islands
Kaho‘olawe Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
State of Hawaii
Hawaiian Islands
Kaua‘i Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
State of Hawaii
Hawaiian Islands
Lāna‘i Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
State of Hawaii
Hawaiian Islands
Maui Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
State of Hawaii
Hawaiian Islands
Moloka‘i Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
State of Hawaii
Hawaiian Islands
O‘ahu Island introduced
invasive
cultivated
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
Japan (offshore islands)
Ogasawara (Bonin) Islands
Bonin (Ogasawara) Islands introduced
invasive
Toyoda, Takeshi (2003) (p. 281)
Naturalized
Japan (offshore islands)
Ogasawara (Bonin) Islands
Bonin (Ogasawara) Islands introduced
Kato, Hidetoshi (2007)
Palau
Palau (Belau ) (main island group)
Babeldaob Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Palau
Palau (Belau ) (main island group)
Babeldaob Island introduced
cultivated
Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 84)
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island introduced
Fosberg, F. R./Sachet, Marie-Hélène/Oliver, Royce (1979) (p. 90)
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island introduced
cultivated
Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 79)
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island   Bishop Museum (Honolulu) (1950) (voucher ID: BISH 152465)
Taxon name on voucher: Acacia confusa Merr.
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island   Beleu National Museum (Republic of Palau. Koror.) (1966) (voucher ID: BNM 414)
Taxon name on voucher: Acacia confusa Merr.
Palau
Palau (Belau ) (main island group)
Koror (Oreor) Island   Beleu National Museum (Republic of Palau. Koror.) (1967) (voucher ID: BNM 413)
Taxon name on voucher: Acacia confusa Merr.
Palau
Palau (Belau ) (main island group)
Malakal (Ngemelachel) Island introduced
cultivated
Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 79)
Palau
Palau (Belau ) (main island group)
Ngerkebesang Island introduced
cultivated
Space, James C./Waterhouse, Barbara/Miles, Joel E./Tiobech, Joseph/Rengulbai, Kashgar (2003) (p. 79)
Philippines
Philippine Islands
Philippine Islands native
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
Philippines
Philippine Islands
Philippine Islands native
ILDIS Co-ordinating Centre (2013)
Philippines
Philippine Islands
Philippine Islands invasive
Merrill, Elmer D. (1923) (pp. 248-249)
On slopes and in open dry forests at low altitudes, very local.
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
China
China
China (People's Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
China
China
China (People's Republic of) introduced
cultivated
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
"Widely cultivated".
China
China
Hong Kong introduced
cultivated
Wu, Te-lin (2001) (p. 129)
Indonesia
Indonesia
Indonesia (Republic of) introduced
ILDIS Co-ordinating Centre (2013)
Japan
Japan
Japan (country) introduced
Mito, Toshikazu/Uesugi, Tetsuro (2004) (p. 184)
Japan
Ryukyu Islands
Ryukyu Islands introduced
ILDIS Co-ordinating Centre (2013)
Malaysia
Malaysia
Malaysia (country of) introduced
ILDIS Co-ordinating Centre (2013)
Singapore
Singapore
Singapore (Republic of) introduced
cultivated
Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 9)
Cultivated only
Taiwan
Taiwan Island
Taiwan Island native
Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 641)
Taiwan
Taiwan Island
Taiwan Island native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Taiwan
Taiwan Island
Taiwan Island introduced
cultivated
Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
"Widely cultivated".
Indian Ocean
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Mauritius
Mautitius Islands (Mauritius and Rodrigues)
Mauritius Island introduced
ILDIS Co-ordinating Centre (2013)
Seychelles
Seychelles Islands
Frégate Island   Robertson, S. A./Todd, D. M. (1983) (p. 51)
Voucher cited: Procter 4172
Seychelles
Seychelles Islands
Seychelles Islands introduced
ILDIS Co-ordinating Centre (2013)

Comments:  This species is being planted in Micronesia. It is a major pest elsewhere. While little reproduction was noted in planted stands, the species should be monitored for invasive behavior. It would probably be wise not to introduce the species to islands where it is not already present (Space & Falanruw, 1999).

An older (probably pre-war) tree was observed in limestone forest on Saipan with no reproduction and a native forest understory, which would indicate limited invasiveness (Space & Falanruw, 1999). Some naturalizing was noted on Rota (Space et al., 2000).

The species is planted in Palau, but no naturalization was noted (Space et al., 2003).

Control: 

Chemical:  "Saplings sensitive to foliar application of 2,4-D at 1 lb/acre and of triclopyr at 1 lb/acre in a trial at Wailua, Kauai.  Triclopyr at 2 lb/acre provided 80% control but 2,4-D at 2 lb/acre caused moderate injury and metsulfuron at 0.4 oz active/acre was ineffective at Kala'e, Molokai. Somewhat tolerant of dicamba. Sensitive to cut-surface applications of 2,4-D, dicamba, glyphosate, picloram (45) and triclopyr in trials at Wailua, Kauai. However, in trials at Kala'e, Molokai, results were less impressive with picloram and dicamba providing serious but not lethal injury and glyphosate and 2,4-D providing moderate injury to Formosan koa. Sensitive to very-low volume basal bark application of 20% triclopyr in oil. Staff at the Hawaii Volcanoes National Park (HAVO) used triclopyr ester at 5% of product in diesel oil applied to the basal bark (Chris Zimmer, HAVO). Tolerant of tebuthiuron pellets."  (Motooka et al., 2003)


Need more info? Have questions? Comments? Information to contribute? Contact PIER! (pier@hear.org)

  [   PIER species lists  ]   [   PIER home  ]

This page was created on 1 JAN 1999 and was last updated on 12 DEC 2010.