Dracaena cinnabari, the Socotra dragon tree or dragon blood tree, is a dragon tree native to the Socotra archipelago, part of Yemen, located in the Arabian Sea. It is named after the blood-like color of the red sap that the trees produce.

The dragon blood tree has a unique and strange appearance, with an "upturned, densely packed crown having the shape of an uprightly held umbrella". This evergreen species is named after its dark red resin, which is known as "dragon's blood". Unlike most monocot plants, Dracaena displays secondary growth, D. cinnabari even has growth zones resembling tree rings found in dicot tree species. Along with other arborescent Dracaena species it has a distinctive growth habit called "dracoid habitus". Its leaves are found only at the end of its youngest branches; its leaves are all shed every 3 or 4 years before new leaves simultaneously mature. Branching tends to occur when the growth of the terminal bud is stopped, due to either flowering or traumatic events.

Its fruits are small fleshy berries containing between 1 and 4 seeds. As they develop they turn from green to black, and then become orange when ripe. The berries are eaten by birds (e.g. Onychognatus species) and thereby dispersed. The seeds are 4-5 mm (0.16-0.20 in) in diameter and weigh on average 68 mg.[4] The berries exude a deep red resin, known as dragon's blood.

Like other monocotyledons, such as palms, the dragon's blood tree grows from the tip of the stem, with the long, stiff leaves borne in dense rosettes at the end (4, 5, 7). It branches at maturity to produce an umbrella-shaped crown, with leaves that measure up to 60 cm (24 in) long and 3 cm (1.2 in) wide. The trunk and the branches of the dragon blood are thick and stout and display dichotomous branching, where each of the branches repeatedly divides into two sections.

Biology

The dragon's blood tree usually produces its flowers around March, though flowering does vary with location. The flowers tend to grow at the end of the branches. The plants have inflorescences and bear small clusters of fragrant, white, or green flowers. The fruits take five months to completely mature. The fruits are described as a fleshy berry, which changes from green to black as it gradually ripens. The fleshy berry fruit ends up being an orange-red color that contains one to three seeds. The berries are usually eaten and dispersed by birds and other animals.

The different shape of the dragon's blood tree is an adaptation for survival in arid conditions with low amounts of soil, such as in mountaintops. The large, packed crown provides shade and reduces evaporation. This shade also aids in the survival of seedlings growing beneath the adult tree, explaining why the trees tend to grow closer together.

Threats

Although most of its ecological habitats are still intact, there is an increasing population with industrial and tourism development. This is putting more pressure on the vegetation through the process of logging, overgrazing, woodcutting and infrastructure of development plans. Though the dragon's blood tree is highly widespread, it has become fragmented due to the development that has occurred in its habitats. Many of its populations are suffering due to poor regeneration. Human activities have greatly reduced the dragon's blood population through overgrazing, and feeding the flowers and fruits to the livestock of the island. One of the species' greatest threats is the gradual drying out of the Socotra Archipelago, which has been an ongoing process for the last few hundred years. This has resulted in non-flourishing trees, and the duration of the mist and cloud around the area seems to also be decreasing. Increasing arid environments is predicted to cause a 45 percent reduction in the available habitat for D. cinnabari by the year 2080.

Additional threats to the dragon's blood tree include harvesting of its resin and use of the leaves to make rope. [citation needed] Presently some of the dragon's blood trees have been used to make beehives. This was generally prohibited; this displays how the species may be threatened by a breakdown in the traditional practices of the island.

The best preserved and largest stand of D. cinnabari is on the limestone plateau named Rokeb di Firmihin. This approximately 540 hectares (1,300 acres) forest has numerous rare and endemic species. Research shows that in coming decades the number of trees in this forest will decrease due to the lack of natural regeneration.