Pacific Island Ecosystems at Risk (PIER)


Corynocarpus laevigatus


RISK ASSESSMENT RESULTS: High risk, score: 7


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

Corynocarpus laevigatus J.R. & G. Forst. Family - Corynocarpaceae. Common Names(s) - Karaka nut, karakaranut, New Zealand laurel. Synonym(s) - .

Answer

Score

1.01

Is the species highly domesticated?

y=-3, n=0

n

0

1.02

Has the species become naturalized where grown?

y=1, n=-1

1.03

Does the species have weedy races?

y= 1, n=-1

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

0

2.02

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

0

2.03

Broad climate suitability (environmental versatility)

y=1, n=0

y

1

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

1

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

2

3.02

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

n=0

n

0

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

n

0

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

y

4

3.05

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

n=0

n

0

4.01

Produces spines, thorns or burrs

y=1, n=0

n

0

4.02

Allelopathic

y=1, n=0

4.03

Parasitic

y=1, n=0

n

0

4.04

Unpalatable to grazing animals

y=1, n=-1

n

-1

4.05

Toxic to animals

y=1, n=0

n

0

4.06

Host for recognized pests and pathogens

y=1, n=0

n

0

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

n

0

4.09

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

y=1, n=0

4.10

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

1

4.11

Climbing or smothering growth habit

y=1, n=0

n

0

4.12

Forms dense thickets

y=1, n=0

y

1

5.01

Aquatic

y=5, n=0

n

0

5.02

Grass

y=1, n=0

n

0

5.03

Nitrogen fixing woody plant

y=1, n=0

n

0

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

n

0

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

0

6.02

Produces viable seed.

y=1, n=-1

y

1

6.03

Hybridizes naturally

y=1, n=-1

6.04

Self-compatible or apomictic

y=1, n=-1

y

1

6.05

Requires specialist pollinators

y=-1, n=0

n

0

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

n

-1

6.07

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

See left

5

-1

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

n

-1

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

1

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

n

-1

7.04

Propagules adapted to wind dispersal

y=1, n=-1

n

-1

7.05

Propagules water dispersed

y=1, n=-1

n

-1

7.06

Propagules bird dispersed

y=1, n=-1

y

1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

7.08

Propagules survive passage through the gut

y=1, n=-1

y

1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

n

-1

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

y

-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

n

1

Total score:

7

Supporting data:

Notes

Source

1.01

(1)No evidence

(1)Stowe, C. J. 2003. The ecology and ethnobotany of karaka (Corynocarpus Laevigatus). M.Sc. Thesis, University of Otago, New Zealand.

1.02

1.03

2.01

(1)Prior to the arrival of Polynesians in New Zealand, karaka was probably restricted in distribution to the Northland/Auckland region. Its natural range was then extended by human translocation and cultivation to the lower North Island, South Island, Kermadec Islands, Chatham Islands and many other in-shore islands off New Zealand.

(1)Stowe, C. J. 2003. The ecology and ethnobotany of karaka (Corynocarpus Laevigatus). M.Sc. Thesis, University of Otago, New Zealand.

2.02

(1)Prior to the arrival of Polynesians in New Zealand, karaka was probably restricted in distribution to the Northland/Auckland region. Its natural range was then extended by human translocation and cultivation to the lower North Island, South Island, Kermadec Islands, Chatham Islands and many other in-shore islands off New Zealand. [native range not well known, and widely planted in Hawaiian Islands and Kermadec Islands marginally subtropical]

(1)Stowe, C. J. 2003. The ecology and ethnobotany of karaka (Corynocarpus Laevigatus). M.Sc. Thesis, University of Otago, New Zealand.

2.03

(1)Habitat Coastal and lowland forest, south to latitude 44°south...It is hardy to zone 8 and is frost tender. (2)Hardiness: USDA Zone 8b: to -9.4 °C (15 °F) USDA Zone 9a: to -6.6 °C (20 °F) USDA Zone 9b: to -3.8 °C (25 °F) USDA Zone 10a: to -1.1 °C (30 °F) USDA Zone 10b: to 1.7 °C (35 °F) USDA Zone 11: above 4.5 °C (40 °F)

(1)http://www.pfaf.org/database/plants.php?Corynocarpus+laevigatus [Accessed 07 Oct 2009] (2)http://davesgarden.com/guides/pf/go/65169/ [Accessed 08 Oct 2009]

2.04

(1)Distribution: Native to New Zealand. Introduced to Kauai in 1891 and naturalized by 1912 in Kökee. Most common at Kökee, Kauai, where it was aerially seeded in 1929; also occurs on Oahu, Molokai, and Hawai‘i (2)Scattered and naturalized in moist soils in the islands. Introduced before 1891 in Kokee region of Kauai and established there. Brought to Molokai before 1912. Afterwards seeds were distributed to other islands. Wild hogs spread the seeds also.

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu. (2)Little Jr., E.L. and R. G. Skolmen. 1989. Common Forest Trees of Hawaii. USDA Agriculture Handbook No. 679. Washington, D.C.

2.05

(1)Prior to the arrival of Polynesians in New Zealand, karaka was probably restricted in distribution to the Northland/Auckland region. Its natural range was then extended by human translocation and cultivation to the lower North Island, South Island, Kermadec Islands, Chatham Islands and many other in-shore islands off New Zealand. (2)Distribution: Native to New Zealand. Introduced to Kauai in 1891 and naturalized by 1912 in Kökee. Most common at Kökee, Kauai, where it was aerially seeded in 1929; also occurs on Oahu, Molokai, and Hawai‘i (3)This plant has been said to grow in the following regions: San Francisco, California

(1)Stowe, C. J. 2003. The ecology and ethnobotany of karaka (Corynocarpus Laevigatus). M.Sc. Thesis, University of Otago, New Zealand. (2)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu. (3)http://davesgarden.com/guides/pf/go/65169/ [Accessed 08 Oct 2009]

3.01

(1)Distribution: Native to New Zealand. Introduced to Kauai in 1891 and naturalized by 1912 in Kökee. Most common at Kökee, Kauai, where it was aerially seeded in 1929; also occurs on Oahu, Molokai, and Hawai‘i (2)Scattered and naturalized in moist soils in the islands. Introduced before 1891 in Kokee region of Kauai and established there. Brought to Molokai before 1912. Afterwards seeds were distributed to other islands. Wild hogs spread the seeds also.

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu. (2)Little Jr., E.L. and R. G. Skolmen. 1989. Common Forest Trees of Hawaii. USDA Agriculture Handbook No. 679. Washington, D.C.

3.02

(1)No evidence

(1)http://www.hear.org/gcw/scientificnames/scinamec.htm [Accessed 07 Oct 2009]

3.03

(1)No evidence

(1)http://www.hear.org/gcw/scientificnames/scinamec.htm [Accessed 07 Oct 2009]

3.04

(1)Karaka is common only on Kauai, where the Division of Forestry planted almost 5000 trees between 1925 and 1937. It is spreading rapidly and is expected to become a noxious weed in the future. On Molokai, it is presently confined to one small patch and will likely be eradicated before it spreads. (2)Environmental impact: Forms monotypic stands. (3)It forms a dense shade excluding other species. It grows in mesic habitats between 700-1,500 m in Hawai‘i (4)Abstract Native species can display invasiveness even in their natural systems. Corynocarpus laevigatus (Corynocarpaceae), karaka, is a tree species apparently native to the north of the North Island, New Zealand, with a history of human cultivation further south, where it appears to be outcompeting other native tree species. Invasiveness was assessed by comparing vegetation in paired plots with and without karaka at 14 sites in forest remnants in the lower half of the North Island. Potential to spread was estimated via dispersal and recruitment patterns around parent trees. Karaka has several “weedy” characteristics. Most seed falls near the parent, but recruitment apparently improves outside the shady canopy, resulting in concentric invasion rings. Compared with nearby non-karaka plots, karaka plots have fewer non-karaka trees, lower abundances of seedlings of other woody species, and slightly higher numbers of exotic species. Karaka appears to be homogenising vegetation, through reduction in herb cover and increase in shrub cover and probably eventual replacement of canopy trees. With its range anthropically extended, management of karaka’s invasiveness appears necessary in lower North Island, South Island, and the Kermadec and Chatham Islands, involving elimination or control, depending on local cultural values. (5)Karakanut (Corynocarpus laevigatus) Kamakou Preserve contains what is believed to be the only population of karakanut on Moloka`i. This invasive, alien, subcanopy tree has become a serious localized weed on Kaua`i. At Kamakou, chemical control (with ROUNDUP applied on cut stumps or frilled trunks) of mature trees and pulling of seedlings and saplings by volunteers over the past three years have nearly eliminated this species.

(1)Little Jr., E.L. and R. G. Skolmen. 1989. Common Forest Trees of Hawaii. USDA Agriculture Handbook No. 679. Washington, D.C. (2)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu. (3)Smith, C. W. 1985. Impact of Alien Plants on Hawai‘i's Native Biota. In: Stone, Charles P. and Scott, J. Michael, eds. Hawai‘i's terrestrial ecosystems: preservation and Management. Cooperative National Park Resources Studies Unit, University of Hawaii, Manoa. (4)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22.

3.05

(1)No evidence

(1)http://www.hear.org/gcw/scientificnames/scinamec.htm [Accessed 07 Oct 2009]

4.01

(1)Description: Tree to 50 ft tall. Leaves 6 inches long by 2.5 inches wide, dark green, thick, margins slightly wavy. Flowers in spring in clusters on upright, stiff stalks, greenish yellow, not showy. Fruits in summer in pendant clusters, orange, flesh thin over a large seed, 1.5 inches long.

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

4.02

(1)Reportedly where trees of this species are removed, native species are not easily established, possibly because root toxins from Corynocarpus remain in the soil...The seeds of Corynocarpus are reportedly poisonous to mammals, while roots appear allelopathic—in producing compounds that inhibit germination of other plant species. [no further evidence found to corroborate this assertion]

(1)Spjut, R. 2004. Investigator’s Report for Scientific Research: Plant Collections from Kauai and Oahu, Hawaii. World Botanical Associates. Bakersfield, CA. Available from http://www.worldbotanical.com/images/WBA%20Hawaii-rpt.pdf [Accessed 30 Sep 2009]

4.03

(1)Description: Tree to 50 ft tall. Leaves 6 inches long by 2.5 inches wide, dark green, thick, margins slightly wavy. Flowers in spring in clusters on upright, stiff stalks, greenish yellow, not showy. [no evidence]

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

4.04

(1)Browsed by deer. (2)Though the foliage and twigs of karaka do not contain the toxin karakin (Skey 1871), they do not appear to be palatable to native herbivorous insects, as little damage is ever seen to foliage above the cattle browse line (JAC pers. obs.); trees will persist in cattle pasture, though no seedlings are observed (Mitcalfe 1969; Stevenson 1978; GLR pers. obs.).

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu. (2)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22 .

4.05

(1)Toxic Part: The uncooked seeds are poisonous, but the ripe flesh of the fruit is edible…There are not adequately documented human poisonings, and clinical descriptions are derived primarily from animal reports, in which administration produces convulsions followed by cardiovascular collapse. (2)As a long-established farmer in the region he has been collecting, selecting and planting karaka trees on his property for many years. This has continued since discovering that, despite their poisonous reputation – how toxic they are seems to depend on how many stomachs you have – cattle seemed to love them. Even sick cattle sometimes came right after a good feed. He has been a karaka fan ever since and a great help to the current research and development project.

(1)Lewis S. Nelson, Richard D. Shih, Michael J. Balick. 2007. Handbook of poisonous and injurious plants. Springer, New York, NY. (2)http://www.maf.govt.nz/sff/about-projects/search/L06-068/karaka-article-from-indigena.pdf [Accessed 30 Sep 2009]

4.06

(1)Nor are leaves liable to disease (except Ashby 1977). (2)Karaka is a large, attractive tree, and relatively fastgrowing for a native. Largely, but not exclusively coastal, it germinates readily from seed and seems largely disease and pest free. In fact it seems suspiciously pest and disease free.

(1)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22. (2)http://www.maf.govt.nz/sff/about-projects/search/L06-068/karaka-article-from-indigena.pdf [Accessed 30 Sep 2009]

4.07

(1)Toxic Part: The uncooked seeds are poisonous, but the ripe flesh of the fruit is edible…There are not adequately documented human poisonings, and clinical descriptions are derived primarily from animal reports, in which administration produces convulsions followed by cardiovascular collapse. [inadvertent poisoning unlikely as long as uncooked seeds are not eaten] (2)Seeds poisonous raw. Maori detoxified them by long cooking (3)Fruit - raw. Sweet and pulpy [1, 2, 46, 59, 61, 103, 173]. One report says that it is poisonous raw [153], though the writer might have been confused with the seed [K]. Seed - cooked[46, 59, 61, 128]. The seed needs to be soaked in salt water or thoroughly boiled or roasted in order to destroy a deleterious principle [1, 2, 63]. A staple food of the Maoris, it contains a tasteless farinaceous substance [2, 103]. The seed contains about 11% protein and 58% carbohydrate [173].

(1)Lewis S. Nelson, Richard D. Shih, Michael J. Balick. 2007. Handbook of poisonous and injurious plants. Springer, New York, NY. (2)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu. (3)http://www.pfaf.org/database/plants.php?Corynocarpus+laevigatus [Accessed 07 Oct 2009]

4.08

(1)Introduced plants that are hard to burn include:..Corynocarpus laevigatus (2)Fire retardant and tolerant plants…includes Corynocarpus laevigatus

(1)http://www.californiachaparral.com/images/Aust_fires_livinginthebush.pdf [Accessed 08 Oct 2009] (2)http://www.burkesbackyard.com.au/forum/3/1/General-discussion/topic/1363 [Accessed 08 Oct 2009]

4.09

(1)Full sun semi-shade and shade (2)Karaka is tolerant of light shade but grows well in full sun.

(1)http://www.nznativeplants.co.nz/shop/Native+Trees/Corynocarpus+laevigatus.html [Accessed 30 Sep 2009] (2)Janick, J. and R. E. Paull. 2008. The encyclopedia of fruit & nuts. Cabi Publishing, Wallingford, UK.

4.10

(1)While tolerant of a wide range of soil types, the soils generally are moist.

(1)Janick, J. and R. E. Paull. 2008. The encyclopedia of fruit & nuts. Cabi Publishing, Wallingford, UK.

4.11

(1)Trees 3-15 m tall; branches stout. Leaves dark green, glossy, thick, coriaceous, elliptic to oblong-obovate, (5-) 10-15 (-20) cm long, (3-) 5-7 cm wide, margins slightly revolute, petioles 1-2 cm long. Flowers in stout, stiff panicles usually 15-20 cm long; sepals suborbicular, ca. 3 mm long; petals greenish yellow, obovate, ca. 5 mm long, margins minutely toothed; staminodes spatulate, minutely toothed. Drupes orange, ellipsoid to ovoid, 2.5-4 cm long

(1)Wagner, W. L., D. R. Herbst and S. H. Sohmer. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press & Bishop Museum Press, Honolulu.

4.12

(1)Environmental impact: Forms monotypic stands. (2)It forms a dense shade excluding other species. It grows in mesic habitats between 700-1,500 m in Hawai‘i (3)Sawyer et al. (2003) reported that there were “several places where aggressive regeneration of karaka is leading to replacement of existing plant communities by stands of karaka”, including the important conservation reserve of Kapiti Island where karaka formed “dense thickets” after elimination of vertebrate pests.

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu. (2)Smith, C. W. 1985. Impact of Alien Plants on Hawai‘i's Native Biota. In: Stone, Charles P. and Scott, J. Michael, eds. Hawai‘i's terrestrial ecosystems: preservation and Management. Cooperative National Park Resources Studies Unit, University of Hawaii, Manoa. (3)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22 .

5.01

(1)Terrestrial

(1)Wagner, W. L., D. R. Herbst and S. H. Sohmer. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press & Bishop Museum Press, Honolulu.

5.02

(1)Corynocarpaceae

(1)Wagner, W. L., D. R. Herbst and S. H. Sohmer. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press & Bishop Museum Press, Honolulu.

5.03

(1)Corynocarpaceae

(1)Wagner, W. L., D. R. Herbst and S. H. Sohmer. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press & Bishop Museum Press, Honolulu.

5.04

(1)Trees 3-15 m tall; branches stout. Leaves dark green, glossy, thick, coriaceous, elliptic to oblong-obovate, (5-) 10-15 (-20) cm long, (3-) 5-7 cm wide, margins slightly revolute, petioles 1-2 cm long. Flowers in stout, stiff panicles usually 15-20 cm long; sepals suborbicular, ca. 3 mm long; petals greenish yellow, obovate, ca. 5 mm long, margins minutely toothed; staminodes spatulate, minutely toothed. Drupes orange, ellipsoid to ovoid, 2.5-4 cm long

(1)Wagner, W. L., D. R. Herbst and S. H. Sohmer. 1999. Manual of the flowering plants of Hawaii. Revised edition. Bernice P. Bishop Museum special publication. University of Hawai‘i Press & Bishop Museum Press, Honolulu.

6.01

(1)No evidence

(1)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22.

6.02

(1)Fruits eaten by feral pigs and the seeds spread thereby.

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

6.03

Unknown

6.04

(1)The present study is the first report of gender dimorphism in Corynocarpus. Corynocarpus flowers were described as bisexual in recent descriptive treatments (Allan 1961; Moore and Irwin 1978; Salmon 1986; Eagle 2006) and the species was not listed among native dimorphic species by Webb et al. (1999). The appearance of the flowers is deceptive because female flowers have anthers that appear fully formed, but these contain no pollen. Similarly, the flowers on male plants have a fully formed gynoecium, but it seems from stigma-staining reactions that the stigma is at best only partly functional...The presence of fruit on most male trees indicates that Corynocarpus is gynodioecious, rather than dioecious or subdioecious, at least in the population studied (see Lloyd 1979; Sakai and Weller 1999 for functional definitions of plant breeding systems). The one polleniferous tree with a high femaleness score probably is a result of overestimation of fruit production in most male trees and does not indicate that tree is an inconstant female. (2)Other potential problems that have come to light relate to the flowering and fruiting behaviour of the trees themselves. Karaka is gynodioecious, which means it has bisexual flowers on some plants and only female flowers on other plants. So not all trees are self-pollinating. While individual trees can have exceptionally heavy crops in some years [at least some trees appear to be self-pollinating]

(1)Garnock-Jones, P. J., R. E. Brockie and R. G. FitzJohn. 2007. Gynodioecy, sexual dimorphism and erratic fruiting in Corynocarpus laevigatus (Corynocarpaceae). Australian Journal of Botany 55: 803–808. (2)http://www.maf.govt.nz/sff/about-projects/search/L06-068/karaka-article-from-indigena.pdf [Accessed 30 Sep 2009]

6.05

(1)Flowers are small, inconspicuous, and probably insect-pollinated (A. W. Robertson pers. comm.) though they are investigated by native birds (I. Castro pers. comm.). (2)The hermaphroditic flowers are small and insect pollinated.

(1)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22. (2)Janick, J. and R. E. Paull. 2008. The encyclopedia of fruit & nuts. Cabi Publishing, Wallingford, UK.

6.06

(1)Propagation. Seed - best sown in a greenhouse as soon as it is ripe[188]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Cuttings of half-ripe wood, July/August in a frame [no evidence of vegetative spread]

(1)http://www.pfaf.org/database/plants.php?Corynocarpus+laevigatus [Accessed 07 Oct 2009]

6.07

(1)trees. New invasion rings spread outwards from the next generation as it reaches reproductive age, which can occur as early as five years (Pigott 1927; M. Greenwood pers. comm.) depending on habitat.

(1)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22 .

7.01

(1)Fruits in summer in pendant clusters, orange, flesh thin over a large seed, 1.5 inches long. [no evidence; large fruits & seeds unlikely to be dispersed unintentionally]

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

7.02

(1)A handsome ornamental or park tree. Grown also in southern California.

(1)Little Jr., E.L. and R. G. Skolmen. 1989. Common Forest Trees of Hawaii. USDA Agriculture Handbook No. 679. Washington, D.C.

7.03

(1)Fruits in summer in pendant clusters, orange, flesh thin over a large seed, 1.5 inches long. [no evidence; large fruits & seeds unlikely to become inadvertent produce contaminant]

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

7.04

(1)Fruits in summer in pendant clusters, orange, flesh thin over a large seed, 1.5 inches long.

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

7.05

(1)If Maori brought karaka seeds across water as oral history describes, then its probable origin was Northland, New Zealand, or nearby islands (Molloy 1990), but a wider Pacific origin is improbable, as it is not water-dispersed (Oliver 1910; JAC pers. obs.).

(1)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22 .

7.06

(1)The fruit are large drupes with orange flesh, each with a single large seed surrounded by endocarp tissue...The single-seeded fruit of Corynocarpus are too large to be swallowed whole by birds other than kereru. Many of its fruit fall to the ground and some are eaten there by rats (Rattus rattus). (2)The New Zealand native pigeon feeds on the fruit of C. laevigatus, and viable seeds are probably transported short distances in the intestinal tract before being voided (Stevenson 1978). However, the fruit contains a toxic component, karakin, which may be fatal if ingested in quantity (Bell 1974). (3)Karaka is clearly bird-dispersed, with its fleshy mesocarp and red-orange exocarp, though it is well shaped to roll considerable distances and is even rather bouncy on hard surfaces. The flesh is strongly scented (Fountain & Couchman 1984), a vertebrate attractant (I. Castro pers. comm.). Fruits are consumed by the native wood pigeon, kereru (Hemiphaga novaeseelandiae; McEwen 1978), the only extant native forest bird with a gape sufficient to ingest whole karaka berries. Though not apparently a favoured part of the diet (McEwen 1978; Powlesland et al. 1997), kereru will gorge karaka before moving to the nearest sunny perch tree to digest their meal and defecate viable kernels (Wilkinson & Wilkinson 1952). Further, the increasing spread of karaka on islands around Auckland has been attributed to improved populations of kereru (Campbell & Atkinson 1999, 2002; Atkinson 2004). Thus, some seed could be dispersed distances of several kilometres via kereru. However, Grice (2004) pointed out that fruits which attract birds may also facilitate the invasion of other weedy bird-dispersed species.

(1)Burrows, C. J. 1996. Germination behaviour of seeds of the New Zealand woody species Alectryon excelsus, Corynocarpus laevigatus, and Kunzea ericoides. New Zealand Journal of Botany 34: 489-498. (2)Wagstaff, S. J. and M. I. Dawson. 2000. Classification, Origin, and Patterns of Diversification of Corynocarpus (Corynocarpaceae) Inferred from DNA Sequences. Systematic Botany 25(1): 134–149. (3)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22 .

7.07

(1)However, the dispersal patterns away from the parent trees recorded in the present study indicate that most fruit falls directly beneath the canopy, with some seeds dispersing up to 40 m away from the parent tree (due perhaps to germination from rodent caches, or to gravitational dispersal). [possibly carried away and cached by rodents]

(1)Costall, J.A., R. J. Carter, Y. Shimada, D. Anthony and G. L. Rapson. 2006. The endemic tree Corynocarpus laevigatus (karaka) as a weedy invader in forest remnants of southern North Island, New Zealand. New Zealand Journal of Botany 44: 5–22 .

7.08

(1)Fruits eaten by feral pigs and the seeds spread thereby.

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

8.01

(1)Tree 20–50 ft (6–15 m) tall, with trunk to 2 ft (0.6 m) in diameter, with rounded crown often flowering as a shrub...Fruit (drupe), elliptical, often unequal sided, 1–11⁄2 inches (2.5–4 cm) long, rarely to 21⁄2 inches (6 cm), hairless, shiny, turning from dark green to yellow to orange, fleshy. Seed single, large, very bitter and very poisonous. [single-seeded fruits unlikely to reach such high densities]

(1)Little Jr., E.L. and R. G. Skolmen. 1989. Common Forest Trees of Hawaii. USDA Agriculture Handbook No. 679. Washington, D.C.

8.02

(1)Storage Behaviour: Recalcitrant [unknown from field conditions]

(1)Liu, K., Eastwood, R.J., Flynn, S., Turner, R.M., and Stuppy, W.H. 2008. Seed Information Database (release 7.1, May 2008) http://www.kew.org/data/sid [Accessed 08 Oct 2009]

8.03

(1)Management: Sensitive to cut-surface (notching) applications of glyphosate. Triclopyr, dicamba, and 2,4-D a little less effective so may require closer spacing of notches(50). Basal bark application of imazapyr effective. Thinline application of Pathfinder® II in vertical streaks effective.

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

8.04

(1)Management: Sensitive to cut-surface (notching) applications of glyphosate. Triclopyr, dicamba, and 2,4-D a little less effective so may require closer spacing of notches(50). Basal bark application of imazapyr effective. Thinline application of Pathfinder® II in vertical streaks effective. [use of herbicide suggests tree is able to reqrow after cutting]

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu.

8.05

(1)Environmental impact: Forms monotypic stands. (2)It forms a dense shade excluding other species. It grows in mesic habitats between 700-1,500 m in Hawai‘i [apparently no natural enemies present locally, and no native or other introduced Corynocarpaceae present in Hawaiian Islands]

(1)Motooka, P., Castro, D. Nelson, G. Nagai, and L. Ching. 2003. Weeds of Hawai`i's Pastures and Natural Areas; An Identification and Management Guide. College of Tropical Agriculture and Human Resources, University of Hawai`i at Mänoa, Honolulu. (2)Smith, C. W. 1985. Impact of Alien Plants on Hawai‘i's Native Biota. In: Stone, Charles P. and Scott, J. Michael, eds. Hawai‘i's terrestrial ecosystems: preservation and Management. Cooperative National Park Resources Studies Unit, University of Hawaii, Manoa.


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