Friday 13 June 2014

The Unique Umbrella Shaped “Dragon's Blood Trees” Which Produced Red Sap


Perhaps the most prominent and distinct plant that evocatively named “Dragon’s Blood Tree” has a unique and bizarre appearance, it is overturned, densely-packed crown having the shape of an upside-down umbrella. Dragon’s blood trees are a unique and slow growing but potentially long-lived species that is very native to the Socotra archipelago off the horn of Africa. It is so popular due to the red sap that the trees produce. The prominent red resin that gives it its name is exuded from the bark after wounding. This evergreen plant is a substance which has been highly prized since ancient times, and has been the major commercial source of this resin, and many myths surround the rare trees. The “dragon’s blood” resin of this tree exudes naturally from fissures and wounds in the bark, and is frequently harvested by widening these fissures with a knife. The resin has had numerous different uses since ancient times, including to color wool, varnishes and plaster, to decorate houses and pottery, and in ritual magic. It is also used for many medicinal purposes, including as an antiseptic, antiviral, anti-diarrhetic, and for treating tumors, and in addition contains compounds with beneficial antioxidant properties.

The medicinal and coloring properties of this resin, and that from other dragon trees, was recorded by the ancient civilizations of Greece and Rome. It continues to be used in medicine, dyes, varnish and incense to this day. Similar to other monocotyledons, such as palms, the tree grows from the tip of the stem, with the long, stiff leaves borne in dense rosettes at the end. However, contrasting too many palms, the dragon’s blood tree branches at maturity to produce the characteristic umbrella-shaped crown with the leaves, which measure up to 60 centimeters long and 3 centimeters wide, remaining crowded at the branch tips. Dragon’s Blood Trees trunk and branches are thick and stout, and show ‘dichotomous’ branching, in which each branch repeatedly divides into two. The first description was made in 1835 when The East India Company led by Lieutenant Wellsted made a survey of Socotra and gives the description to Pterocarpus Draco, but in 1880, the Scottish botanist Isaac Bayley Balfour made a formal description of the species and renamed it as “Dracaena Cinnabari”. Of between 60 and 100 Dracaena species, D. Cinnabari is one of only 6 species which grows as a tree.

The tree usually flowers in Feb; however exact flowering time may vary and depends on location. Normally flowers grow at the ends of the branches, comprises of branched inflorescences bearing clusters of small, fragrant, white or greenish flowers. The fruit usually takes five months to completely develop, which is small fleshy berry that transform from green to black as it ripens, to end becoming orange-red, and containing between one and three seeds. The berries may be eaten by animals and birds, including domestic livestock, which then act as seed dispersers.

Due to its unique flora and fauna, the Socotra Archipelago is designated as a World Heritage Site, a WWF Global 200 Ecoregion, a Centre of Plant Diversity and an Endemic Bird Area, and it also lies within the Horn of Africa biodiversity “hotspot”. Numerous initiatives are underway to aid sustainable development and biodiversity management on Socotra & the dragon’s blood tree is considered an important flagship species for conservation on the island, and an “umbrella species”, whose protection would also benefit many other plants and animals.

 Dragon’s Blood Tree is usually found at elevations of 300 to 1,500 metres, preferring limestone-based soil and naturally growing in evergreen or semi­-deciduous woodland. It is the only tree-forming Dracaena species to form dense woodland and frequently appears to grow well in areas of solid rock pavement with wide-ranging cracks, down which water and soil can flow after rains, however; as long as moisture and nourishment for the roots. The tree’s pattern of distribution closely matches the areas of the island that experience normal low cloud, rain and drizzle during the monsoon season.

The Drangon’s Blood Tree bizarre shape assists to survive in often arid conditions and on mountaintops with little soil. Early morning mists condense on the waxy, skyward-pointing leaves, the water then channeling down the trunk to the roots. The vast densely packed crown also offers highly effective shade, so dropping the evaporation of any water drops that fall to the ground, and giving shade to the tree’s roots. This shading allows seedlings to survive better beneath the adult tree than in full sun, which could be why many dragon’s blood trees grow close together.

The dragon’s blood tree is still relatively widespread, but its range has become abridged and fragmented, and various populations are suffering from poor regeneration. Though human activities may have play a bigger contribution to this deterioration, like overgrazing and the feeding of the flowers and fruit to livestock, the main threat to the species is thought to come from the gradual drying out of the Socotra Archipelago, a process that has been ongoing for the last few hundred years, but which may be exacerbated by global climate change. In many cases, the trees are failing to flourish, and the extent and duration of the mist and cloud brought by the monsoon appears to be decreasing. Growing aridity is foreseen to cause a 45 % dropping in available habitat for this species by the year 2080.

Other impending threats to the dragon’s blood tree, such as harvesting of its resin and the use of its leaves to develop rope, have decreased in recent years and are currently small-scale, but in future rise in demand could potentially lead to over-collection. Some dragon’s blood trees have been felled to make beehives. Though this was usually condemned, and it illustrates how the species may be threatened by a breakdown in traditional practices on the island.
  



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