THE DEPLETED FOREST COVER OF SRI LANKA, REDUCED RAINFALL AND WIND DAMAGE TO BUILDINGS.
The forest cover of Sri Lanka based on aerial photography, as stated in the Biological Conservation Report of 1993 of the International Union for Conservation of Nature (1UCN) is as follows:
1956 : 44%
1992 : 20.24%
The reduction of the forest cover commenced in the British Colonial period with the clearing of forests for the cultivation of coffee. The first coffee plantation of 10 acres was established in 1825, during the tenure of Governor Sir Edward Barnes. (Tennent 1859). In January 1856, the area under coffee was 71300 acres. (Balasigham : ' The administration of Sir. Henry Ward). In the early 1860s, the ' Coffee Boom' collapsed due to ' Black Bug' (Hemeleia Vastarix). In 1867, the first tea plantation of Sri Lanka was established with 10 acres of Loolkandura Estate by Mr. James Jaylor and subsequently coffee was replaced by Tea. The progress of Tea cultivation is started by David Crole in ' Tea' (1897) as follows:
1867 - 10 acres
1877 - 2,720 acres
1887 - 70,000 acres
1896 - 330,000 acres
A. The decrease of forest cover between 1825 and 1956 could tabulated as follows:
Period | Percentage decrease | Annual rate of decrease of forest cover. |
1825-1956 (132 years) | 100-44 = 56% | 56 - 132 = 0.42% |
The decrease of the forest cover during this period is due to the following:
- Clearing forests for Coffee and Tea plantations by the British.
- Clearing forests for Colonization schemes from 1931, inaugarated by Mr. D.S. Senanayake.
- Clearing forests for teak planting to replace tropical timber trees in dryzone forests, with ' timber contractors extracting indigenous tress.
- Clearing forests for the Galoya Project since 1949
- Clearing forests for Walawe Project since 1954
B. Decrease of forest cover from 1956 to 1992.
Period | Percentage decrease | Annual rate of decrease of forest cover. |
1956 to 1992 (37 years) | 44-20.24 = 23.76% | 23.76 |
The decrease of the forest cover during this period is due to the following:
- Expansion of areas for new planting for Tea, Rubber, Coconut and spices.
- Continuation of timber extraction by contractors in dry zone forests.
- Clearing forests for colonization schemes.
- Encroachments of state land in the country.
- Continuation of forest clearing for the Galoya Project.
- Continuation of forest clearing for the Walawe Project.
- Forest clearings for systems B.C.G and H of the Mahaweli Project commencing 1968.
Clearing forest for assorted projects such as :-
- Kondechchi cashew plantation in Mannar District.
- Mankorny cashew plantation in Eastern Province.
- Pelwatte Sugar Company in Moneragala District.
- Kantale Sugar Corparation in Trincomlalee District.
- Tamankaduwa Dairy Project.
- Bataata cotton project.
- Feeling of trees, illict or otherwise for timber and furniture.
C. The forest cover depletion from 1992 to date.
Continuation of forest clearings for systems B.C, G and H of the Mahaweli Project for peasent alienation.
Expansion of Mahaweli Projects under Moragahakanda, Kaluganga , Malwathu oya, Yan oya and Wemedilla, reservoirs and channel schemes with forest clearings for peasent alienation, reservoirs and infrastructures. Sometimes timber contractors seem to possess miraculous powers as was shown in a news telecast on 3rd April 2017 in a state TV channel, where a timber contractor with a permit to extract timber from areas to be inundated by the Moragahakanda Reservoir for a limited period in 2015, continued to use the same permit to extract timber even by April 2017! He was reported to be felling and removing Satinwood from areas treated as reservations beyond the limit of the inundation and inspite of the complaints of the villages to the relevant authorities, the contractor was continuing the felling and transport of timber from the reservation.
§ Illicit felling of timber trees throught the Island, accelerated with the increasing use of power operated chain saws to cater to the increasing demand for roof timber and furniture by the rapidly increasing population.
§ Encroachments on state lands.
D. Reduction in annual rainfall in various parts of the island.
Even as farback as 1897 Darid Crole states about Sri Lanka in his ' Tea' that ' if the forests be depleted to a much further extent, it must surely affect the climate of the crown colony by seriously diminishing the amount of its rainfall.' Perhaps this was a hypothesis in 1897 and many would still assume it to be as such.
The closest incidence which would support this is the great famine which followed a severe drought lasting several years in the last decade of the 20th century in Ethiopia. The cause of this drought was traced to the cutting down of forests in the highlands of the country, to produce firewood for the population. It is believed now that the ' seeding of rain clouds' is due to forests. In Ethiopia, reforestation was done the rectify the situation.
The recurrent droughts in various ports of the country during the past few years could possibly be due to the depleted forest cover, which was 20.24% in 1992 , would have dropped still further down during the last 25 years, and had reached some critical pint to cause these droughts.
E. Wind damage to building roofs in the Dry Zone.
Wind damage to buildings in the dry zone plains is a common occurrence now and a few instances are quoted below:
Date | Location Mihintale | Details |
09.08.2017 | Dehiaththakandiya | Roofs of buildings and houses destroyed. Trees uprooted in town. |
04.09.2017 | Mihintale and Polonnaruwa | Roofs of houses destroyed. |
05.09.2017 | Kaduruwela | 75 buildings and houses had their roofs destroyed. |
14.09.2017 | Tantririmale | 10 houses had their roofs destroyed. |
A complete forest cover keeps the wind above the crowns of the trees and provides complete protection beneath the trees. With the development of settlements, the forests are ' blanket cleared' and followed by infrastructure building and houses, with isolated trees left behind as rejects by timber extraction contractors. Winds now develop eddying an turbulence and cause destruction to the roofs of buildings. Studies by western scientists clarify this situation and stress the importance of trees to prevent eddying and turbulence and avoid damage by winds.
Yasantha De Silva.
BSc. (Agriculture)
Email: ydesilva2013@gmail.com
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