Hymenaea L. is a genus in the family Fabaceae (legume family). Of fourteen living plant species in the genus, all but one are native to the tropics of the Americas, with one additional species (Hymenaea verrucosa) on the east coast of Africa. The genus is distributed through the Caribbean islands, and from southern Mexico to Brazil. In Colombia the trees are called algarrobo, and in Peru azúcar huayo. The Brazilian name is jatobá.

Most species of Hymenaea are large trees and they are primarily evergreen. They may grow to a height of 25 meters and emerge above the forest canopy. Some species will grow both as tall forest trees and as smaller shrubby trees depending on their surrounding habitat. The leaves are bifoliolate, meaning that they have two leaflets attached to the petiole. The flowers grow in a panicle or corymb type of inflorescence.

Uses and properties

The pulpy center of the fruits are edible and contain starch. The fruit is sold in local markets in the Americas. The leaves may be used to make a tea. The trees produce a dense wood used for timber in making ships and furniture. The thick bark of some species is used by indigenous people of the Amazon to make canoes. Seeds contain large amounts (40% of dry weight) of a highly viscous polysaccharide (xyloglucan) which can be used in several industrical sectors such as food, paper, cosmetic and pharmaceutical.

The trees also make hard resins that are used to manufacture varnish, especially the resin from Hymenaea courbaril (jatobá) in Brazil. The resin that is produced in Brazil is known as South American copal, and Hymenaea verrucosa is the source of the valuable Zanzibar copal. Resin may be collected from living trees, or from the soil near the place where a tree once stood. Throughout its American range, indigenous peoples use the resin for incense and as a cement. Resin from the extinct species Hymenaea protera is the source of Dominican amber and probably of most amber found in the tropics.

In the neotropical region, Hymenaea courbaril has become an example of tropical tree plant species that responds to the global climatic changes in course in our planet. It increases photosynthesis by ca. 60% and cellulose by 30% when grown under 720ppm of CO2, the atmospheric concentration expected for the year 2100 if carbon dioxide (one of the main green house effect producing substances on Earth) emission continue to increase in the same rate.

Seedling establishment is promoted by xyloglucan mobilization during development in Hymenaea courbaril. Seeds germinate after about 18 days and start xyloglucan mobilization after 45 days. This takes place for abuout 20 days, when photosynthesis is established and the seedling becomes independent.

One of the signs that storage mobilization is occurring is that young leaves become red due to the presence of anthocyanins.

Seedlings from the rain forest invest 70% of their carbon in the aerial parts whereas the one from savannah invests more carbon (ca.70%) on root development.

Hymenaea is a very important species in programmes of recuperation of degraded Rain Forests in the Neotropics. Regarding ecological succession, Hymenaea courbaril appears late in the process being classified as a 'late successional' or climax species.

See also

• Dominican amber
• Animé, an oleo-resin from Hymenaea species.
• Jatobá, the economically important Brazilian tree H. courbaril.

References

• Aidar M.P.M., Martinez C. A., Costa A. C., Costa P. M. F., Dietrich S. M. C., Buckeridge M. S. (2002) Effect of atmospheric CO2 enrichment on the establishment of seedlings of jatobá, Hymenaea courbaril L. (Leguminosae, Caesalpinioideae) Biota Neotropica. 2(1):(http://www.biotaneotropica.org.br/v2n1/en/abstract?article+BN01602012002).
• Buckeridge, M.S. & Aidar, M.P.M. (2002) Carbon sequestration in the rain forest: alternatives using environmentally friendly biotechnology. Biota Neotropica 2(1): (http://www.biotaneotropica.org.br/v2n1/en/item?point-of-view).
• Gentry, Alwyn H. (1996). A Field Guide to the Families and Genera of Woody Plants of Northwest South America (Colombia, Ecuador, Peru). Chicago: University of Chicago Press. ISBN 0-226-28944-3.
• Lima, D.U., Chaves, R.O. & Buckeridge, M.S. (2003) Seed storage hemicelluloses as wet-end additives in papermaking. Carbohydrate polymers 52:367-373.http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFD-47WD89K-6&_user=10&_coverDate=06%2F01%2F2003&_alid=467430042&_rdoc=3&_fmt=summary&_orig=search&_cdi=5224&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=ed9d7ea0f98ad90eddd946d7478fc693
• Lee, Yin-Tse & Langenheim, Jean H. (1975). Sytematics of the Genus Hymenaea L. (Leguminosae, Caesalpinioideae, Detarieae). University of California Publications in Botany 69.
• Mabberley, D. J. (1987). The Plant Book: A Portable Dictionary of the Higher Plants. Cambridge: Cambridge University Press. ISBN 0-521-34060-8.
• Poinar, George Jr. & Brown, Alex E. (2002). Hymenaea mexicana sp. nov. (Leguminosae: Caesalpinioideae) from Mexican amber indicates Old World connections. Botanical J. of the Linnaean Soc. 139(2): 125.
• Santos, H.P., Purgato, E., Mercier, H. & Buckeridge, M.S. (2004) The Control of Storage Xyloglucan Mobilization in Cotyledons of Hymenaea courbaril L. Plant Physiology 135:287-299.http://www.plantphysiol.org/cgi/content/abstract/135/1/287
• Santos, H.P. & Buckeridge, M.S. (2004) The Role of the Storage Carbon of Cotyledons in the Establishment of Seedlings of Hymenaea courbaril Under Different Light Conditions. Annals of Botany. 94(6) 819-830.http://aob.oxfordjournals.org/cgi/content/full/94/6/819