Holywood lignum vitae  (Guaiacum sanctum)

The Holywood lignum vitae (Guaiacum sanctum) is classified as Endangered (EN) on the IUCN Red List (1) and listed on Appendix II of CITES (2).

The holywood lignum vitae (Guaiacum sanctum) is a stunning tree which produces beautiful blue flowers, either solitarily or in clusters (3) (4). These flowers have five petals and usually measure just over a centimetre across (3).

The leaves of the holywood lignum vitae comprise of three to five pairs of dark green leaflets, which measure about three centimetres in length and have a small point at the tip. During the hottest part of the day, the leaflet pairs may sometimes fold together (3). The fruits of this species have four or five lobes and are bright orange-yellow when mature. They open to expose red, fleshy arils (seed coverings) which contain the hard, black, rounded seeds (3) (5). The seeds of the holywood lignum vitae measure about one centimetre in length (3).

The holywood lignum vitae generally grows as a relatively low tree with a gnarled truck and a spreading, rounded crown of drooping branches (3) (5). Its wood is notable for its unique greenish-brown colour. The wood is strong and dense, and sinks when placed in water (4) (6).

The native range of the holywood lignum vitae is from Panama, north through Central America to Mexico as well as across most of the Caribbean islands from Cuba east to Puerto Rico (1) (4). It is also present in Florida in the United States where it is found in the Florida Keys (5).

The holywood lignum vitae typically grows in lowland dry forest or scrub (1) (4), as well as in woodland, thickets, pasture, plains and on hillsides. It is usually found near the coast at lower elevations inland (4).

As a broadleaf evergreen tree, the holywood lignum vitae is conspicuous in the dry season, when most of the other surrounding plants are leafless (6). It produces many blue flowers throughout the year, but more frequently in the warmer months between March and August. The fruits of the holywood lignum vitae are produced simultaneously with or subsequently to these flowers. During the fruiting period the tree may bare fruit continuously for up to six weeks (3) (5).

The holywood lignum vitae may play an important role in the forest ecosystem, providing vital resources and niches for many other species. As well as providing cover for several species of bird, its seeds also provide a food source  to many species. These birds either consume the seeds themselves or transport them for consumption by nestlings or fledglings (5).

The holywood lignum vitae has a very slow growth rate (4) (6) and it has been known to live for up to 1,000 years (5).

‘Lignum vitae’ is Latin for ‘wood of life’, which was derived from the fact that the holywood lignum vitae has long been known for its medicinal uses. It produces a gum or resin that acts as a stimulant and induces sweating. It has been known to relieve gout, chronic rheumatism, and is used in blood-purifying compounds and as an anti-inflammatory (4) (6). In Jamaica, it is even soaked in rum and used as a gargle for  sore throats (6).

The wood of the holywood lignum vitae is also highly sought after for its desirable qualities of strength, toughness and density. The wood is largely used as a building material for, producing structures such as ship propeller shafts, mallets, caster wheels and stencil and chisel blocks (4) (6) (7).

The main threat the holywood lignum vitae faces is over harvesting. The tree is sought after for both its high quality timber and medicinal resin, which are of commercial value and have been traded for several centuries (1) (4) This has led to intense logging, making it extremely rare across its entire range (1) and close to local extinction in 11 countries (8). The holywood lignum vitae was previously found in El Salvador, but has now gone regionally extinct there (1) (4). Regeneration of the holywood lignum vitae is being encouraged, but due to the slow growth rate of this species progress is slow (1).

The holywood lignum vitae is also under threat from habitat loss. For example, in the Florida Keys, it is under threat from development for retirement homes (4).

The holywood lignum vitae is included on the convention on the Convention on International Trade in Endangered Species (CITES) Appendix II regulates its international trade (2). There has been recent consideration of it being re-categorised to CITES Appendix I, making international trade of wild trees illegal (4). This species is also found in some protected areas. For example, in Mexico the holywood lignum vitae is protected at ten sites, with the majority of the area protected being located in the Calakmul region in Campeche (8).

Unfortunately, the holywood lignum vitae is likely to continue to decline unless the rate of habitat loss is reduced. Protected areas will be needed to help safeguard the future of this heavily exploited tree (8).

Find out more about tree conservation:

• The Global Trees Campaign
  http://www.globaltrees.org/