Conserving the Ceylon Ebony Tree

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Ebony Sapling at Gampaha Botanical Gardens

The Sri Lankan Ebony tree (“Ceylon Ebony”) was described in scientific terms for the first time by the Baltic German botanist Johann König in 1796. Its botanical name is Diospyros ebenum and belongs to a family of trees known as Ebenaceae. Ebony grows in both topical and intermediate climes found in Sri Lanka, and are known to take about two centuries to reach maturity.

Called “Karuwala” (“dark”) in Sinhala, the wood of the ebony tree has been in demand from ancient times for the manufacture of curios, and has historically had a high commercial value. Ebony is classified as “Super Luxury Class” timber and was sold at premium prices at the timber auctions held by the State Timber Corporation, for logs with a mid girth of over three and a half feet. Ceylon Ebony is rarely found in the global market today.

The heartwood of Ebony is rich black with a narrow and even interlocked grain, and has a fine texture once sawn and planed. The timber is of high density and classified as a hardwood. Seasoning is unnecessary, as Ebony contains little moisture, and shrinkage doesn’t occur.  The timber is durable and has a strong immunity to borer or termite attacks. Ebony is used today to make decorative, high-class furniture, and curios and implements, which fetch high prices in both the domestic and the foreign market.

EbonyLog-STC

Cross-section of an Ebony log, State Timber Corporation

The extravagant black, smooth finish of ebony made it a raw material for the manufacture of exclusive furniture for the upper classes of a bygone era. The possession of “Karuwala Putu” (Ebony couches), “Karuwala Meesa” (Ebony chairs) or “karuwala Almari” (Ebony closets) was considered a status symbol in the 19th and early 20th centuries. Ebony is used today to make musical instruments, especially piano keys. It is also used to turn out ornamental curios such as gem-studded elephants.

Legend has it that a particular powder that is made of certain leaves and bark of trees, when stored in a jar made out of ebony, exhibits a strange potential. Put a dot of this powder on your forehead, and pesto! You can move about invisibly!

Irrespective of its commercial value and supposed magical properties, the Ebony tree is a majestic creation of nature that deserves admiration, respect and conservation. Overexploitation for development projects, illicit felling, deforestation for human habitation, destruction during the last war against terrorism, and the inefficiency of the forestry department are some of the major reasons for the drastic reduction in Sri Lanka’s forest cover in general, and for the dwindling of Ebony in particular. The Ebony tree is on the Red List of threatened fauna and flora of Sri Lanka (pub. 2007), and is currently an endangered species.

Until fairly recently, people were accustomed to use endemic hardwood species to make traditional furniture. There was a misconception in the minds of many, that there are very few species of trees that are durable for commercial use as quality timber. The inherent durability of timber is not an essential feature in the light of modern technology. The application of modern treatment technology renders inherently non-durable timber that is not endemic (such as Pinus, Acacia, Eucalyptus or Rubber wood) to become even more durable than the traditional hardwoods. With appropriate machining and coloring, these low-cost woods can be made attractive and durable for all commercial purposes including the making of elegant furniture.

Lets us always remember the natural and cultural heritage that is Ebony, and preserve it for future generations to see, and perhaps even exploit with care. For those of you who are interested, I’ve listed several other fascinating facts about Ebony, its use and conservation.

Geographic distribution

Ebony is found mainly in the dry zone tropical forests of northern Sri Lanka, and in a few isolated areas in the central province and the wet zone to the south. In the north, it is also found in the Jaffna peninsula, except in the offshore islands. Ebony is found sporadically in other parts of the island such as in Kaluthara, Hambanthota and Monaragala.

Ebony grows well in waterlogged, fertile soil of clay and sand. It grows even in mountain areas above 1300m above sea level, and is found in Hantana, Gangamuwa, Hinidum Kanda and Erathna.

Classification

König classified Ebony as follows:

  • Kingdom (Division) – Plantae (Plant)
  • Sub Kingdom – Tracheobionta (vascular plant)
  • Super Division – Spermatophyta (seed plant)
  • Division – Magnoliopsida (Dicotyledon)
  • Sub Class – Dilleniidae
  • Order – Ebenales
  • Family – Ebenaceae
  • Genus – Diospyros
  • Species – Diospyros ebenum

Similar species in the family Ebenaceae are endemic to other countries in the South Indian region, which have similar climatic and soil conditions, such as India and Malaysia. Ebony is called Karun-kali in Tamil, is known in Malaysia as Karu or Mush Timbi, and is called Ebans and Abnus in Hindi.

Botanical description

Ebony is a perennial plant, and reaches a height of around 15m at maturity. Its leaves are evenly distributed, each leaf being 5~10 cm in length and 2.5~6.0 cm in width. The leaves obstruct the sunlight and heat from falling on to the base of the plant. The shape of the leaf is oval and oblong; some leaves are chocolate or brownish green. Surface is usually marked with a clear lateral vein.

The color of the flowers rang from yellow to white, and are mostly deciduous rarely monoicous. The male flowers are comparatively small and found in clusters, while the females plants bare flowers singularly, and these flowers are epipetalous. The appearance of the male and female plants is the same, but the male flowers are bigger and sessile. The flowers have a funnel shaped calyx that separate into four sepals, and a white tubular shaped corolla.

The fruit of the Ebony tea is dark green, oval shaped, and about 2cm in diameter. The corolla is larger and thicker than the corolla in the flower. When the outer corolla of the fruit is removed, you’d see 2~8 seeds, which are brown in color.

The bark of the tree covering the trunk and branches ranges from gray to black in color. The inner (minor) bark ranges from brown to yellow. The sapwood usually has a lighter shade. The heartwood is mostly pitch black, with slightly gray strips found in some specimens.

Composition of the timber

The mid girth of the tree is about a meter at maturity. The Ebony tree is generally cylindrical and a straight log of about 5 meters in length, sans bends, could be extracted from a mature specimen. A cross section taken from such a mature log would show the composition of the log from the bark up to the heartwood. The bark of the log, which is the hard outer cover, appears dark brown. Next is the sapwood region that ranges from dark brown to gray, and covers the heartwood. Black streaks are commonly found in the sapwood. At the center you’d see the heartwood, which is the dense inner part of the tree. The heartwood is pitch black, and rarely shows light colored streaks. Its appearance is quite impressive, and once converted into sawn and smoothed timber, it shows a metallic luster. The timber has no smell to speak of, but can be easily identified because of it remarkable black color and high density.

Annual growth rings are clearly seen when examining a cross section of the tree trunk. It is markedly visible in the sapwood. The vessels are comparatively very small, so small the ducts that carry water cannot be seen easily in the sapwood. If you observe carefully you might see how the vessels are lined up singularly and in clusters of two and three. There are about four to twelve vessels in a single square mm. A single vessel is around 380~510 microns and has a dense wall the diameter of a single cell (about 200~215 microns). There are no tyloses in the vessels, and rarely you’d come across brown deposits in the sapwood. The vessels in the heartwood carry deposits that could be seen in brown and black.

The parenchyma consists of paratracheal cells surrounding the vessels and independent apotracheal cells.

You will see the rays in the heartwood through a powerful lens (10X) within a range of about a millimeter; there are 11~16 rays close together.

The chemical composition of Ebony timber is:

  1. Water
  2. Lignin
  3. Pentosans
  4. Cellulose
  5. Alcohol (benzene soluble)
  6. NaOH (0.2% soluble)
  7. Xylose, Mannose and Balactose
  8. Humic acid

Physical properties

Scientific research was carried out by the faculty of civil engineering of the Moratuwa University and the national building research organization (NBRO), to ascertain the following physical properties of Ebony.

  • Moisture content% – 9~12 % (dry stage)
  • Density (Kg/m3) – 1127.6 Kg/m3
  • Bending Strength, Modulus of Rupture (MOR) – N/mm2
  • Bending Strength, Modulus of Elasticity – 17984.3 N/mm2
  • Compressive Strength, Parallel to Grain – 63.15 N/mm2
  • Compressive Strength, Perpendicular to Grain – 30.1 N/mm2

Growth

At the beginning there is a show growth rate, which accelerates later in the tree’s life. Generally the growth rate (height) is 0.25 to 1.2cm per annum. To have a mid girth of around 120 cm (i.e. a matured tree) it would take around 190~200 years of growth. The recorded average girth according to age is as follows.

Years Mid girth (Inches)
25 18
75 36
135 45
200 72

Laws for harvesting

Sri Lankan law bans the harvesting and export of Ebony timber without a special permit. Permits can be obtained for limited Sri Lankan applications and for the export of finished goods through the respective provincial secretaries. However the export of Ebony in the forms of logs or sawn timber is strictly prohibited.

Related species

Other species of Diospyros family in Sri Lanka:

  1. Diospyros ovalifolia (in Sinhala Kanu Malla), found in low country tropical zone inter monsoon forests
  2. Diospyros thwaitesii (in Sinhala Riti Kudumberiya), found in low country wet zone rainforests
  3. Diospyros racemosa (in Sinhala Kaha kaala – Kalu walla), found in low country wet zone forests
  4. Diospyros walkeri (in Sinhala Madiriya Kudum-beriya), found in low country wet zone rainforests
  5. Diospyros malabarica (in Sinhala Thimbiri), low country dryzone intermonsoon forests
  6. Diospyros melanoxylon (in Sinhala Kudumberiya-kalu-thimbri), low country dry zone monsoon rainforests
  7. Diospyros ferrea (in Sinhala Kalu Habaraliya), low country dry zoon monsoon forests
  8. Diospyros insignis (in Sinhala Wal Madiriya), low country wet zone rainforests
  9. Diospyros montana (in Sinhala Gini Bulu), low country dry zone
  10. Diospyros oocarpa (Kalu Kudumberiya), low country dry zone inter monsoon forests
  11. Diospyros hirsute (Madiriya), low country wet zone rainforests
  12. Diospyros acuminate (in Sinhala Ulmadiriya), low country wet forests
  13. Diospyros quaesita (in Sinhala Kalu Mediriya), low country wet forests and dry zone

Ebony and Kalu Mediriya are very similar trees. The Ebony timber is pitch black and so is Kalu Mediriya, except that it has white streaks and grains. The other physical and chemical characteristics of Kalu Mediriya are more or less similar to Ebony.

Market

According to classification made by state timber corporation based on quality, scarcity, supply, and demand, Ebony timber is classified as super luxury timber. The heartwood is extracted and sold, and softwood goes to waste. Ebony does not come under free sale at S. T. C. Sales Depots, simply due to unavailability.

The commercial stocks come mostly from illicit timber, from a limited number of trees marked by the Forestry Department for harvesting, and from fallen trees disposed of by the Forestry Department. Only those persons registered at the National Crafts Board at Battaramulla are issued with a ration of Ebony timber. As such, the potential global demand for Ceylon Ebony cannot be supplied at present. Black market prices for timber are unverifiable, but can be judged by the prices found in other countries such as the USA, where a single board-foot would cost well over USD 100.00.

Conservation

The ministry of environment with the support of the biodiversity secretariat, the national species conservation advisory group and the national exports commission on biodiversity, has jointly published the Red Databook-2007 to describe endangered species in Sri Lanka.

Ebony is on this list of endangered species. As such, it is the prime responsibility of the authorities concerned in our country to take appropriate steps to conserve and adopt sustainable development methods for Ebony. The tree faces several threats that may ultimately render it extinct.

  1. Large scale illicit felling and harvesting of timber by unauthorized but organized groups.
  2. Inefficiency or negligence of authorities employed by the state to protect the forest and ensure sustainable development; authorities who do not enforce prevailing laws and regulations, or use them for private objectives.
  3. The slow growth rate of ebony and other endemic species.
  4. Climate change and other environmental reasons. The plant cannot resist extreme dry weather conditions.
  5. Deforestation due to development and human encroachment.
  6. Destruction due to fire, caused by man and by nature.
  7. Inadequate firebreaks and other preventive measures to stop the spreading of fire by storms and wind.

Story | Cyril Wickramatunga
Photography | Ruwan Rajapakse (Ebony Sapling), The State Timber Corporation (Ebony Log)

1 Comment

  • Hi,

    Nice article.

    Any chance of getting Kalu mediriya plants?

    I have checked every where and failed.

    Kaluwara plants are widely available at Forestry Dept.

    Best,
    Heminda
    0777332296

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