Acacia_koa

From Wikipedia, the free encyclopedia Acacia koa Acacia koa Koa A young koa tree showing compound leaves and phyllodes Scientific classification Kingdom: Division: Class: Order: Family: Subfamily: Tribe: Genus: Species: Plantae Magnoliophyta Magnoliopsida Fabales Fabaceae Mimosoideae Acacieae Acacia A. koa Upper branches of a koa tree, showing the bark, sickle-shaped phyllodes, greenish rounded flower heads, and seed pods Leaves Initially, bipinnately compound leaves with 12–24 pairs of leaflets grow on the koa plant, much like other members of the pea family. At about 6–9 months of age, however, thick sickle-shaped "leaves" that are not compound begin to grow. These are phyllodes, blades that develop as an expansion of the leaf petiole. The vertically flattened orientation of the phyllodes allows sunlight to pass to lower levels of the tree. True leaves are entirely replaced by 7–25-centimetre (2.8–9.8 in) long, 0.5–2.5-centimetre (0.20–0.98 in) wide phyllodes on an adult tree.[3] Binomial name Acacia koa A.Gray The koa (Acacia koa) is a species of flowering tree in the pea family, Fabaceae. It is endemic to the Hawaiian Islands,[1] where it is the second most common tree.[2] The highest populations are on Hawaiʻi, Maui and Oʻahu. Flowers Flowers of the koa tree are pale-yellow spherical racemes with a diameter of 8–10 millimetres (0.31–0.39 in).[6] Flowering may be seasonal or year round depending on the location.[3] Description Koa is a large tree, typically attaining a height of 15–25 metres (49–82 ft) and a spread of 6–12 metres (20–39 ft).[3] In deep volcanic ash, a koa tree can reach a height of 30 metres (98 ft), a circumference of 6 metres (20 ft), and a spread of 38 metres (120 ft).[4] It is one of the fastest-growing Hawaiian trees, capable of reaching 6–9 metres (20–30 ft) in five years on a good site.[5] Fruit Fruit production occurs when a koa tree is between 5 and 30 years old. The fruit take the form of pods with a length of 7.5–15 centimetres (3.0–5.9 in) and a width of 1.5–2.5 centimetres (0.59–0.98 in). Each pod contains an average of 12 seeds. The 6–12 millimetres (0.24–0.47 in) long, 4–7 millimetres (0.16–0.28 in) wide seeds are flattened 1 From Wikipedia, the free encyclopedia ellipsoids and range from dark brown to black in color. Seeds are covered with a hard seed coat, and this allows them to remain dormant for up to 25 years. Scarification is needed before A. koa seeds will germinate.[6] Acacia koa electric guitars as well,[16] and still uses a koa-veneered topwood on certain models.[17] Commercial silviculture of koa is difficult because it takes 20 to 25 years before a tree is of useful size.[18] Fender also made a Limited Edition Koa wood Stratocaster in 2006 & it is no longer available. Habitat Koa is endemic to the islands of Hawaiʻi, Molokaʻi, Maui, Lānaʻi, Oʻahu, and Kauaʻi, where it grows at elevations of 100–2,300 metres (330–7,500 ft). It requires 850–5,000 millimetres (33–197 in) of annual rainfall. Acidic to neutral soils (pH of 4-7.4)[3] that are either an Inceptisol derived from volcanic ash or a well-drained Histosol are preferred.[7] Its ability to fix nitrogen allows it to grow in very young volcanic soils. [2] Koa and ʻōhiʻa lehua (Metrosideros polymorpha) dominate the canopy of mixed mesic forests.[8] It is also common in wet forests.[9] Relation to other species The relationships of koa are not clear. Among other Pacific Islands of volcanic (non-continental) origin, only Vanuatu has native Acacia species. A. heterophylla, from distant Réunion, is very similar and has been suggested to be the closest relative of koa, but this is far from certain.[19] Uses Koaiʻa seed pod, showing the end-to-end arrangement of seeds. A closely related species, koaiʻa or koaiʻe (A. koaia), is found in dry areas. It is most easily distinguished by having smaller seeds that are arranged end-to-end in the pod, rather than side-by-side. The phyllodes are also usually straighter, though this character is variable in both species. The wood is denser, harder, and more finely grained than koa wood.[3] Koaiʻa has been much more heavily impacted by cattle and is now rare, but can be seen on ranch land in North Kohala. The American country singer Taylor Swift with a Taylor acoustic guitar made of Acacia koa wood The koa’s trunk was used by ancient Hawaiians to build waʻa (dugout outrigger canoes),[10] and papa heʻe nalu (surfboards). Only paipo (bodyboards), kikoʻo, and alaia surfboards were made from koa, however; olo, the longest surfboards, were made from the lighter and more buoyant wiliwili (Erythrina sandwicensis).[11] The reddish wood is very similar in strength and weight to that of black walnut (Juglans nigra), with a specific gravity of 0.55,[6] and is sought for use in wood carving and furniture.[3] Koa is also a tonewood,[12] often used in the construction of ukuleles,[13] acoustic guitars,[14] and Weissenborn-style Hawaiian steel guitars.[15] B.C. Rich used koa on some of their Conservation The koa population has suffered from grazing and logging. Many wet forest areas, where the largest koa grow, have been logged out, and it now comes largely from dead or dying trees or farms on private lands. Although formerly used for outrigger canoes, there are few koa remaining which are both large and straight enough to do so today.[3] In areas 2 From Wikipedia, the free encyclopedia where cattle are present, koa regeneration is almost completely suppressed. However, if the cattle are removed, koa are among the few native Hawaiian plants able to germinate in grassland, and can be instrumental in restoring native forest. It is often possible to begin reforestation in a pasture by disk harrowing the soil, as this scarifies seeds in the soil and encourages large numbers of koa to germinate.[7] Experiments at the Hakalau National Wildlife Refuge have shown that ʻōhiʻa lehua (Metrosideros polymorpha) survives best in pasture when planted under koa. This is because koa trees reduce radiative cooling, preventing frost damage to ʻōhiʻa lehua seedlings.[20] Acacia koa Gallery Acacia koa with phyllode between the branch and the compound leaves References [1] "Acacia koa", Germplasm Resources Information Network (United States Department of Agriculture), 2007-04-30, http://www.ars-grin.gov/cgi-bin/npgs/ html/taxon.pl?313146, retrieved on 2009-02-23 [2] ^ Idol, Travis (2008-04-16). "Environmental Controls Over Acacia koa Productivity". Travis Idol’s Research Page. University of Hawaiʻi at Mānoa. http://www2.hawaii.edu/~idol/ research.html. Retrieved on 2009-01-31. 3 From Wikipedia, the free encyclopedia [3] ^ Elevitch, Craig R.; Kim M. Wilkinson; J. B. Friday; C. Baron Porter (April 2006) (PDF). Acacia koa (koa) and Acacia koaia (koaiʻa). The Traditional Tree Initiative. http://www.agroforestry.net/tti/Acaciakoa.pdf. [4] Welsbacher, Anne (2003). Life in a Rain Forest. Twenty-First Century Books. p. 30. ISBN 9780822546856. http://books.google.com/ books?id=86X9ryA0NKUC&client=firefoxa. [5] Wilkinson, Kim M.; Craig R. Elevitch (2003). Growing Koa: A Hawaiian Legacy Tree. Hōlualoa, Hawai’i: Permanent Agriculture Resources. p. 13. ISBN 9780970254429. http://books.google.com/ books?id=J0-uxZN9SVMC&client=firefoxa. [6] ^ Allen, James A. (2003-01-01). "Acacia koa A. Gray" (PDF). Tropical Tree Seed Manual. Reforestation, Nurseries & Genetics Resources. http://www.rngr.net/ Publications/ttsm/ Folder.2003-07-11.4726/ Acacia%20koa.pdf/file. Retrieved on 2009-02-23. [7] ^ Whitesell, Craig D. "Koa". Silvics of North America Volume 2: Hardwoods. United States Department of Agriculture. http://www.na.fs.fed.us/spfo/pubs/ silvics_manual/volume_2/acacia/koa.htm. Retrieved on 2009-02-17. [8] Ziegler, Alan C. (2002). Hawaiian Natural History, Ecology, and Evolution. University of Hawaii Press. pp. 175-176. ISBN 9780824821906. http://books.google.com/ books?id=l56J_8teG58C&client=firefoxa. [9] Sohmer, S. H.; R. Gustafson (1987). Plants and Flowers of Hawaiʻi. University of Hawaii Press. pp. 45-52. ISBN 9780824810962. http://books.google.com/ books?id=6roh_cQf1N0C&client=firefoxa. [10] Bryan, William Alanson (1915). Natural History of Hawaii, Being an Account of the Hawaiian People, the Geology and Geography of the Islands, and the Native and Introduced Plants and Animals of the Group. Hawaiian Gazette Co, Ltd. p. 339. http://books.google.com/ books?id=SfkJAAAAMAAJ. Acacia koa [11] Marcus, Ben; Juliana Morais; Jeff Divine; Gary Linden (2007). The Surfboard: Art, Style, Stoke. MBI Publishing Company. pp. 17-19. ISBN 9780760327531. http://books.google.com/ books?id=HGN2uGL_YcC&client=firefox-a. [12] Beberman, Norman L.. "Koa: Beautiful Looking, Beautiful Sounding Tonewood". GuitarNation.com. http://www.guitarnation.com/articles/ koa.htm. Retrieved on 2009-02-23. [13] Total Ukulele: D-Tuning Method for Beginners. Mel Bay Publications. 2002. p. 93. ISBN 9783802404467. http://books.google.com/ books?id=_wRCs2Sr3kgC&client=firefoxa. [14] Gerken, Teja (2000). Acoustic Guitar Owner’s Manual: The Complete Guide. String Letter Publishing. p. 10. ISBN 9781890490218. http://books.google.com/ books?id=MJ7Lq1jk8cMC&client=firefoxa. [15] Sheperd, John (2003). "Guitars". Continuum Encyclopedia of Popular Music of the World. Volume II: Performance and Production. Continuum International Publishing Group. p. 283. ISBN 9780826463227. http://books.google.com/ books?id=pJvzEzjahkQC&client=firefoxa. [16] Achard, Ken (1989). The History and Development of the American Guitar. Bold Strummer Ltd. p. 163. ISBN 9780933224186. http://books.google.com/ books?id=jytNSlng8g4C&client=firefoxa. [17] Kirkland, Eric (December 2006). "Rich and Famous". Guitar World: 154. [18] "Silviculture: Diversification of Rural Economy". Leeward Haleakalā Watershed Restoration Partnership. http://www.lhwrp.org/?c=silviculture. Retrieved on 2009-02-01. [19] Whitesell, Craig D (1964) (PDF). Silvical Characteristics of Koa (Acacia koa Gray). United States Forestry Service. http://www.fs.fed.us/psw/publications/ documents/psw_rp016/psw_rp016.pdf. [20] Friday, J. B.; Darrell A. Herbert (April 2006) (PDF). Metrosideros polymorpha (‘ōhi‘a lehua). The Traditional Tree 4 From Wikipedia, the free encyclopedia Initiative. p. 21. http://www.agroforestry.net/tti/ Metrosideros-ohia.pdf. Acacia koa External links • Photos of Acacia koa at Hawaiian Ecosystems at Risk Project (HEAR) • UCLA botanical garden and home • Historic photos and descriptions of Acacia koa Retrieved from "http://en.wikipedia.org/wiki/Acacia_koa" Categories: Acacia, Trees of Hawaii, Endemic flora of Hawaii This page was last modified on 12 May 2009, at 20:09 (UTC). All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.) 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