Forestry and Enironment Symposium 2000, Sri lanka

Sixth Annual Symposium of the Department of Forestry and Environmental Science, Sri Lanka. 15- 16 December 2000, Kandy, Sri Lanka

Wednesday, November 01, 2006


G. A. Dayathilaka,K. C. E. Fernando S. Senarathne
Department of Crop Science Faculty of Agriculture,University of Ruhuna

Red sandalwood is a tree species originated in India, which is highly prized for an array of medicinal and industrial uses, and thus being over exploited from their natural habitates. Since there is no systematic cultivation, at the face of increased exploitation red sandalwood has become an endangered species. The population size in Sri Lanka has limited only to just a few trees which were introduced from India. The number of seed bearing trees are limited further compelling to initiate a tree multiplication program.

At the wake of this situation, the current work was started to develop a rapid multiplication program for red sandalwood employing sexual and asexuel means of propagation. After a through survey a cluster of four red sandal wood trees including two bearing trees were found to obtain seeds and vegetative material. Seeds fallen under the tree, which were collected daily and hand picked fully mature seeds were used for germination studies, Seeds were found extremely recalcitrant and lose viability within a week. Prior to germination, wings of the seeds were clipped and pre treated as follows; over night soaking mechanical removal of hard seed coat, gibberalic acid treatment. Eventhough, the tetrasolium test proved that seeds are viable (before germination), there were no signs of germination over a period of one month. Subsequently it was found that, seeds are not viable anymore, Seeds seem quiescent, not ready for germination and loose viability soon due to its recalcitrant nature.

Vegetative propagation is attempted via, air layering, stem cuttings and through tissue culture. Induction of root formation was tried with the application of auxins: NAA and IBA under mist propagation in sand medium. Double modal cuttings with a triplet of leaves were used in semi-hard wood type material, while the same without leaves was used in hard-wood. Callus formation and the formation of root primodia has started from 6-8 weeks after planting in semi-hard wood with leaves. In the hard wood, cut surface was completely covered with reddish-purple colour stain. There was no sing of the formation of calllus or root primodia. Callus formation was obtained from leaf disks with auxins and cytokinins in woody plant (WP) medium

Keyworks: Pterocarpus santilinus, seed germination, vegetative propagation


J.M. T. D. Evarad S. A. C. N. Perera
Genetics and Plant Breeding Division, Coconut Research Institute

Coconut has been recognized as a crop with tremendous potential for alleviating poverty in the third world. Its' importance however, as an oil crop and a source of income generation for poor farmers' incomes. The low productivity constraints need to be identified accurately and dealt appropriately to gain maximum benefits of coconut and hence proper identification, collection, evaluation and conservation of coconut genetic resources in the country was recognized as an essential step towards developing strategies for enhancing incomes of small holder. On the other hand the genetic erosion of coconut has reached an unprecedented ark due to natural disasters, land fragmentation and competition from other crops.A search for coconut genetic resources was initiated in 1984 with emphasis on collecting drought tolerant germplasm and subsequently for random collecting to capture a more genetically representative sample. These collections are conserved ex-situ in 11 CRISL gene banks. To date, the number of collections has reached 100, constituting 7 drought tolerant, 51 random, 7 seed palm (plus palm), 8 exotic and 17 distinct phenotypes Data (standard morphological descriptors) are being constantly gathered from these ex-situ accessions for their genetic evaluation. Descriptor-data and DNA polymorphisms have been assessed in a sample population and a narrow genetic base was observed among most common tall coconuts of the country. Molecular data unveiled a gamut of information on population's structure of the coconut in Sri Lanka and their roots of origin.Utilisation of coconut germplasm was looked in two dimensions, use of desirable characters, such as jelly-like endosperm of dikiri coconut for confectionery and small bodiri nut as a beverage, for income generation of poor-farmer families and use of genetically diverse accessions for production of new hybrids. Importation of germplasm was envisaged as a high priority for enrichment of coconut germplasm in the country.


K. K. I. U. Aruna Kumara U. Wickramasinghe R. Senarathne
Department of Crop Science Faculty of Agriculture,
University of Ruhuna

This experiment was undertaken primarily to study the influence of salinity on root formation of curttings, taken from four promising salt-tolerant species, namely Acacia leucophioea (Katu andara), Cassia autriculata (Ranawara), The.spe.sia populnea (Suriya), and Salvadora persica (Malittha).Here, semi hard wood cuttings of each species were planted in poly bags filled with soil, and arranged RCBD with four replicates. Saline solutions (i.e., 2, 4, 8 and 12 dS/m) were applied at the rate of 100,1 per poly bag, once in two days up to the period of one month. Sea water (40 dS/m) diluted to give varying salinity levels and normal water (0.13 dS/m) was used as the control. The experiment was conducted, during the period of March,-June 2000, at the Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, Sri Lanka.The results of the study indicated that any of four species did not form roots, even in the control. Thus, experiment was repeated, and carried out up to the period of two months. At the end of two months, Suriya had formed several roots and other 3 species did not form roots at all. Highest rooting percentage and highest root elongation were obtained in low salinity levels (<4> 8dS/m)According to this study, rooting is considered as a very difficult task in cuttings of Katu Andara, Ranawara and Malittha. But for Suriya it can be considered as successful method of propagation.


G. N. Chandrasiri U. A. D. P. Gunawardene
Department of Forestry and Environmental Science
University of Sri Jayewardenepura

Air pollutjon is arguably the most important, in terms of economics cost, or tne various types of pollution caused by transport and industrial activities and its effects have been widely studied in other countries. However, direct studies have not been undertaken to measure the economics cost of air pollution in Sri Lanka.

Concern for air pollution in Sri Lanka is focused mainly in Colombo. Although Colombo air pollution level is less than many Asian countries, recent monitoring results show that air pollution from particulate matter and Sulfur is well above the WHO recommended level.

The contingent valuation method was used to estimate the air pollution cost and data was collected from a contingent valuation survey carried out in the Fort and Pettah areas. Respondents' willingness to pay values were obtained for a hypothetical market presented. The results were consistent with the economic theory. Aggregated cost of air pollution for the country was Rs.55 million per year. This value may help cost benefit analysis of air quality management programmes and other related development policy and programs in Sri Lanka.


W. G. Somarathne
Agricultural Resource Management division Hector Kobbekaduwa Agrarian Research & Training Institute

Neo-liberal market oriented policy measures have shown hot to be harmful to the agro-environmental management, at lease in the present situation in high and mid country in Sri Lanka (Somaratne, 1998). However, macroeconomic policies alone are not adequate to address the land degradation problem in the upland regions. In this context, the other complementary economic and environmental policy instruments are needed to combat micro-level land degradation-induced environmental damages.

In this analysis, two environmental policy options, replacement of present seedling tea lands in high and midland regions with Vegetatively Propagated (VP) tea and adoption of sloping agricultural Land Technology (SALT) are selected as possible micro-level environmental policy options to mitigate the cost of land degradation. In order to select the viability of environmental policy options, the cost-benefit analysis (CBA) method is employed as an analytical device. These policy options show considerable promise as viable micro level environmental policy options to mitigate land degradation-induced agro-environmental damages in the high and midland regions of Sri Lanka.

Key words - Land degradation; Agro-environmental management; vegetatively propagated (VP) tea; S+loping Agricultural Land Technology (SALT); and Cost-benefit Analysis (CBA)


M. T. N. Fernando1 K. B. Dissanayaka1 P. G. Joshep2
Coconut Research Institute Alternative Energy Division, Ministry of Power and Energy

Growth of the demand for electricity intimately follows the growth of the economy of Sri Lanka. Since the hydro resources, the major source of electricity are insufficient to meet the growing demand for electricity, alternative power sources have to be employed. Gliricidia proves to be a promising source of biomass energy. Firms generating dendro-thermal power express their willingness to establish dendro-thermal power plants at the Coconut Research Institute of Sri Lanka on build-operate and transfer (BOT) basis, and to purchase Gliricidia dry wood delivered at the power plant at Rs. 1250/MT. This study examines whether the farmers can supply Gliricidia at the above price with a reasonable margin for them. The break-even price of a MT of dry wood delivered at the power plant located 10 km from the coconut estate was computed employing discounted cash flow method. This was Rs.977, implying a margin of some 28% for growers. The analysis further demonstrated that the break-even price was more sensitive to variations in wood yield than the variations in transporting distances. The ex-ante appraisal concludes that the raising of Gliricidia under coconuts as an energy source for dendro-thermal power plants is an economically viable proposition. However, other socio-economic factors influencing the adoption of new technologies may be worth investigating.


Malik Ranasinghe
Department of Civil Engineering University of Moratuwa

Large extents of paddy lands are abandoned in the North Western Province. Even though low productivity of paddy lands and lack of water at the correct times seem to be the obvious reasons, the economics of paddy cultivation is as or more important reason for abandoning large extents of paddy lands in this fertile province.

This paper describes, the engineering that was needed to convert paddy lands to those on which teak trees could be planted; the extended benefit cost analysis of planting teak trees in five hectares of abandoned paddy lands; the barriers and the constraints to obtaining approval for a project that could provide obvious environmental benefits; and the actual experiences and behaviour of the engineered project; as the case study.

The engineering that was needed to convert paddy lands, which were on level surfaces to those on which teak trees could be planted without refilling, is described. The levelling, design and construction of canals to provide drainage and minor irrigation to the teak plantation, and the actual experiences and behaviour of the engineered project are highlighted.

The extended benefit cost analysis considered the opportunity cost of abandoned paddy. lands, the economic cost of engineered waterways that are needed to convert paddy lands to those on which teak trees could be planted, the economic cost of land preparation and planting, and the economic and environmental benefit of teak trees. This analysis clearly shows that planting teak trees in abandoned paddy lands is economically and environmentally viable option.

According to the Agrarian Services Act No.58 of 1979 it is mandatory to obtain permission from The Commissioner of Agrarian Services prior to commencing any activity other than growing paddy in paddy lands. The experiences; barriers and constraints to obtaining approval for a project that had obvious environmental benefits to society is described with suggestions on how to improve on the approval process.

As a result of the analysis of the case study, the paper concludes that planting teak trees in abandoned paddy lands in the North Western Province of Sri Lanka is economically and environmentally feasible. Therefore, it is an activity that should be encouraged as part of agricultural forestry or industrial crop cultivation in abandoned paddy lands.


K. W. Gunawardena S. C. Wijeyaratna
Department of Botany University of Sri Jayewardenepura

Studies on lichens at Ritigala Mountain revealed that a marked variation exists in the distribution and diversity of lichens with change in elevation. Light and moisture are two main environmental factors that changed the microclimate, which in turn determine the distribution of lichens at different elevations. Most of the lichens recorded on the barks of trees and rocks at lower elevation belonged to genera such as Dirinaria, Graphis, Parmelia, Psyxine, Pyremula and Parmotrema and, Leptogium. At mid elevation (i.e. between 400 - 500m contour line) diversity and distribution found to be much different from those at lower elevations. Crustoses such as species of Myreotrema, Thelotrema, Porina, Phyllospora, Ocellularia and several sterile ones were found on tree trunks and rocks. However, the lichen diversity of the crowns of trees at mid elevation seems to be somewhat similar to that at lower elevation although tree species are different. At mid elevation, tree trunks get only diffused light while the canopy gets more direct light. The difference in distribution and diversity observed on barks could mainly be due light condition prevailing at mid elevations.

At elevations above 600m, genera observed were very much different to those found at lower levations. Commonest genera recorded were Heterodeeermiu, Pseudocyphellaria, Sticta, Collema, Leptogium and Parmelia. Al higher elevations, it is cool but sunny during the day while nights are cooler and wet due to mist. Thus, differences observed with respect to lichen diversity could be due to the difference in microclimate that prevails at higher elevations.

Air quality studies indicated that air pollution due SO2, is minimal in this area.This research reveals that Mount Ritigala supports extremely interesting and diverse lichen community which has not yet been explored fully yet. Similar to vascular plants, lichens show a marked zonation in the distribution of various species. This could be mainly due to differences in the microclimate at different attitudes. As lichens are sensitive to changes in the microclimate (specially with respect to air pollutants) it is important that the prevailing conditions are maintained. Any activities that lead to severe atmospheric pollution may cause significant changes in the existing lichen diversity.


K. N. G. Pushpakumara1 H. B. Kotagama2
1Department of Crop Science Faculty of Agriculture
University of Peradeniya 2Department of Agricultural Economics Faculty of Agriculture University of Peradeniya

Biodiversity can be defined as variety and variability of living organisms. Conceptually, it can be defined as hierarchically related levels, genetic, species and ecosystems. Culture and related developments also plays a significant role in biodiversity. It is widely accepted that biodiversity is central to the development and evolutionary process without which the sustainability is questionable.

However, Sri Lanka is loosing biodiversity is disappearing rapidly at all levels. At gene level, example is loss of wealthy landraces and local cultivars. At species level, extinction, overexploitation and smuggling cause loss of species. Ecosystems also subjected to series of changes due to various reasons. Cultural aspects and indigenous knowledge also loose at a rapid rate.

The challenges for these biodiversity losses cannot be address by simple or single measures. A number of compatible options are essential to address it. However, the use of biodiversity in an appropriate manner is suggested as one of the most effective options in conservation of biodiversity.

Use of biodiversity requires bioprospecting, the search for wild species, genes and their products with actual or potential use to humans. In broadest sense, it is a process dating from the roots of humanity. It has been practiced informally throughout Sri Lanka and elsewhere. The formalisation of this process brings more benefits to the soicety. However, if the benefits of biodiversity utilisation are to be shared fairly and equitable, governments will needs to design specific mechanisms to ensure that these benefits actually reach intended beneficiaries which is termed as benefit sharing. This is an important issue from the article 15 of the Convention of Biodiversity, which Sri Lanka signed and ratified.

Biodiversity prospecting and benefit sharing increase in the recognised value of resources are the most effective pathways to foster conservation and the continued availability of biodiversity. The authors are discussing the above issues with examples from India and Costa Rica and their relevance to Sri Lanka

Key words: biodiversity; conservation; biodiversity prospecting; betlfitsharing.


W. L. D. P. T. S de A. Goonatilake D. K. Weerakoon
Department of Zoology,University of Colombo

In recent times, canopy studies have revealed a wealth of information about the arthropod diversity that can be seen in the forest canopy. For instance, Stork (1997) sampled 19 trees of Luehea seemannii, a tree found in semi-evergreen forests of Brasil, which yielded 955 species of beetles. Another canopy study done in venezuela yielded 972 species of beetles from six rain forest trees (Davies et al., 1997). However, in Sri Lanka, no studies have been done so far regarding the canopy arthropods.

This study was done as a pilot project to assess the canopy arthropod diversity in Sri Lanka. The study was conducted in the Peak Wilderness Sanctuary from March to May 1999. A single tree of the common canopy species Campnosperma zeylanica (Anacardiaceae), was selected and the knockdown pesticide Cyfluthrin, was applied to the canopy using 'Swin Fod SN50' fogger. Arthropods falling from the tree were collected on to plastic sheets suspended 1 m above the ground level and preserved in 70% alcohol. Arthropods were assigned to taxonomic orders and approximate morphospecies..

A total of 228 individuals belonging to 18 orders were collected. These individuals were separated into 111 morphospecies. Of the morphospecies recorded, the highest number belongs to order Diptera (33) followed by order Hymenoptera (22), order Araneida (14), and order Coleoptera (12). Rest of the orders were represented by 5 or less morphospecies. These results are based on a single sample collected in March 1999. Yet a large number of species were recorded indicating that the canopy arthropod diversity in Sri Lanka is likely to be very high. Therefore, further investigations should be carried out to assess the actual diversity that exist in the forest canopy of Sri Lanka.


C. N. B. Bambaradeniya S. P. Ekanayaka B. Kekulandala M. J. J. Fernando P. Samarawickrama N. Rathnayaka
IUCN-The World Conservation Union

Muthurajawela wetland, located as the west coast of Sri Lanka is the largest coastal peal bag of the island. At present, the biodiversity of Muthurajawela is threatened by unplanned development activities and growing human population. Therefore, an ecological survey was carried out in order to assess the present status of biodiversity in Muthurajawela, and also to identify critical habitats for the conservation and sustence of biodiversity. Field monitoring of fauna and flora was carried out at fortnightly intervals, using scientifically accepted rapid biodiversity assessment techniques (fauna - line transects; flora - plots, Braun-Blanquet cover), The data was analysed using ecological indices (diversity/species richness), and critical habitats were identified using avifauna asa correlate of biodiversity.Ground truthing of vegetation maps was carried out to document changes of major vegetation communities.

The study enabled to identify 192 species of flora, distributed over seven major vegetation communities at Muthurajawela; marsh, lentic flora, reed swamp, short grassland, scrubland, stream bank flora and mangrove swamp. The vertebrate fauna documented included 40 species of fish, 14 species of amphibians, 31 species of reptiles, 102 species of birds and 22 species of mammals. Among the total vertebrate species documented, 17 are endemic, 26 are considered as nationally threatened, while 36 are new records to Muthurajawela. The selected. invertebrate species documented consisted of 48 species of butterflies and 22 species odonates, the latter which turned out to be a useful indicator of habitat quality. The threats documented included direct exploitation (poaching, cutting of trees), habitat degradation/modification (land reclamation, dumping of garbage, clearing of natural vegetation, pollution and eutrophication) and the spread of several alien invasive species (including unmanaged domestic animals). The northern part of the marsh serve as an ecotone, with a mixture of the above plant communities/habitat types which were relatively undisturbed. Analysis carried out using ecological indices highlighted the northern region as a high biodiversity zone, which is critical for the conservation and future sustenance of biodiversity at Muthurajawela. Ground truthing of vegetation maps, supported with results of the vegetation survey showed that the composition of dominant flora has changed over a period of 10 years, in most places in the Muthurajawela Wetland, as a result of human disturbances. Data on the avifauna also highlighted a considerable decrease in migrant birds at Muthurajawela, possibly due to habitat deterioration.The findings have important conservation and management implications, in particular greater emphasis need to be placed on the more ciritcal areas of the marsh. An important policy implication would be the need to avoid any conversions of these critical habitats which harbour rich biodiversity


V. P. Perera
Department of Wildlife Conservation

The Mahaweli wildlife region is mostly in the dry zone of the country with 1993. 44kmZ of protected areas. There are about 500-800 elephants habitats in this region. The Human Elephant Conflict (HEC) in this region intensified in the last few years, due to the civil war and Accelerated Mahaweli development scheme. This study is explored the (1) The DS divisional-wise distribution pattern of human and elephant mortalities, (2) The causes of elephant mortalities and (3) How the HEC affect on the rate of elephant extinction. The data for the study is based on cases reported to the Department of Wildlife Conservation between 1990-2000 and descriptive post mortem finding of most recent 25 elephant mortalities. The possible causes of deaths, ages, breeding efficiency and physiological status were evaluated during post mortems using various indicators. Between 1990-1999> 316 elephant mortalities and between 1992-1999, 105 human mortalities have been recorded. The sex ratio of elephants that died were 3.18 male: 1 female. The postmortems findings revealed the causes of death as 12% natural, 64% gun shot injuries, 8% electrocution, 8% railway accidents and 8% drowned in canals. Among those that were shot, 69% were injured by automatic guns, 25% by shotguns and 6% by trap guns. The 72% males that died, 68% were good sound breeding bulls, between 15-35 years of age.

Many scientists have attributed the HEC to the associate with rainfall and cultivation pattern. Today the lands are cultivated year round and the HEC is spread throughout the year. The present rate of elephant mortality, sex imbalance and weakening of the gene pool due to the death of breedings bulls, all contribute to the extinction of this flagship species.


K. S. Mahalekamge1 S. Piyasiri2
1Department of Forestry and Environmental Science
University of Sri Jayewardenepura
2Department of Zoology University of Sri Jayewardenepura

Kandy Lake is an ornamental fresh water body in Sri Lanka, which was built by the last king of the Country, the King Sri Wickrema Rajasinghe between 1810 and 1812. The quality of the lake water has been investigated since 1979 and these results indicated that the lake faces the problem of eutropication. The appearance of Microcystis bloom during mid April 1999, indicated the severity of the organic pollution. A large number of effluent canals drain in to the lake carrying a continuous flow of sewage and domestic waste matter. The existing information suggests high nitrates and phosphate concentration in the lake.

The objective of the present study is a preliminary survey of plankton species, which can be used as biological indicators to determine the water quality an the level of eutropication of the lake. A hypothesis has been tested on preliminary basis, which has to be improved through detailed experimental investigations in future.

Field investigation were carried out in Kandy Lake from Jan.-June 2000. Information collected was analyzed to determine Physico-chemical properties of the lake water, composition of plankton species, their relative abundance and relationship between nutrients and prominent plankton species.Majority of the total plankton density was composed of phytoplankton compared to zooplankton density of the lake. Therefore it is impossible to use top down control of algal biomass using zooplankton in Kandy lake as in many other tropical water bodies

Bacillariophyceae was the most abundant group during most months of the year. Melosira spps also contributed significantly towards the biomass of lake plankton. The Most prominent plankton spps of the lake was Microcystis aeruginosa which belongs to the group Cyan bacteria. There was a direct correlation, between Microcysti.s number and the amount of phosphate present in the lake water, which could be used in developing a bio indicator determining trophic status of lakes. At the beginning of the study both. Microcystis density and phosphate levels were high. With the decrease of phosphate level, Microcystis density decreased and Melosira species gradually became the domenant species.

The Zooplankton composition was made up of Copepods, Cladocerans and rotifers. Species composition was high among rotifers and a clear-cut seasonal variation was observed among them. The majority of the zooplankton was small in size and their influence on the phytoplankton community could be considered as negligible due tohigh phytoplankton biomass. All the zooplankton recorded in the study belongs to the category of typically tropical zooplanktons.

There is a significant relationship between Microcystis density and Orthophosphate level which could be used in determining status of eutropiicatioe of the lake


1S. P. Periyapperuma 2Ajith de Alwis
1Department of Forestry and Environmental Science University of Sri Jayewardenepura
2Department of Civil Engineering University of Moratuwa

The degradation of lakc environments and resources is now a world-wide issue. Efforts urgently have to be made to restore the friendly coexistence of lakes and humankind through appropriate management of lake/watershed systems to assure the sustainable use of their resources.In this project the Boralesgamuwa Lake, which is one of the most distinctive landmarks within the town limits of Maharagama had been studied. The rapid urbanization of the town has led to the environmental deterioration of the lake exacerbated by numerous out falls discharging nutrient rich water into this stagnant body of water.

Objectives of the study were identification of sources of polluting the Boralesgamuwa lake, significant impact of pollution, and designing and developing a suitable mitigating strategy. There isn't any water quality monitored data relating to the Boralesgamuwa lake. During this study, pH, conductivity, temperature, DO, BOD, COD, nitrate, phosphate and the coliforna levels of the lake water were examined & also several sources of polluting the lake were identified. About 30 surface water samples were analysed during Feb. 2000 to July 2000. Heavy metal pollution of the lake was also examined. Physicochemical characteristics of the Boralesgamuwa lake water showed significant site-specific & time-bound variations during the study period.

The phosphate concentration in surface water close to wastewater discharging point,of,one garment factory is comparatively high. During the month of April phosphate concentration at that point was comparatively low, because at that time the factory was not working. At the point, where the urban waste water drainage line is entering the lake, the nitrate concentration is fairly high. Most of the lake surface is covered with macrophytes and with very high amount of the water hyacinth (Eichornia). The coli form count of the lake is also very high. The MPN (Most Probable Number) is more than 1000 per 100 ml for the most of the locations. The faecal coli form count is also very high. Unauthorized settlers and enchroachments are common factors of the lake reservation.

The industry concerned is already doing primary treatments and they are discharging their effluents according to the CEA standards. But the problem is still there. There are no industrial effluent standards for phosphate in Sri Lanka. Proposed mitigating strategies for these negative impacts
1.For phosphate reduction
1.1Chemical treatment
1.2Biological treatment
2.For urban waste water
2.1 A central waste water treatment plant should be installed
3.For reduction of faecal contamination
3.1 A sewerage system should be designed
4.Unauthorized settlers and enchroachments
4.1 Unauthorized settlers and enchroachers should be resettled.__Proceedings of


Samanmali Abeysiri D. M. S. H. K. Ranasinghe
Department of Forestry and Environmental Science,
University of Sri Jayewardenepura

Global warnvng is one of the major environmental issues on earth caused by the anthropogenic activities. This is brought about by the greenhouse effect due to accumulation of greenhouse gases in the earth's atmosphere. Carbon dioxide (COZ) is the major contributor to the greenhouse effect.

This research project was carried out with two objective viz. to quantify the amount of carbon stored in the teak (Tectona grandis) plantations in Sri Lanka and to quantify the amount of carbon sequestered in different ages of the plantation.

The quantification of the carbon stored in the current standing teak plantations in Sri Lanka is based on the Forest Department Inventory Database - The FORDATA. The data were acquired as a sub block mean and were calculated using standard formulae to quantify the divisional value and the country value. Only the merchantable volume of the bole wood had been considered in this study, since that is the portion, which lasts for a long time without releasing its carbon storage to the atmosphere. The data obtained from the FORDATA database was field verified in three (3) major teak growing forest divisions in the country, namely Kurunegala, Puttalam and Anuradhapura.

The amount of carbon dioxide trapped in the state owned teak plantations in Sri Lanka, currently without being emitted to the atmosphere for a long time is 608,62 Gt C and the mean carbon storage of teak plantations (rotation length was taken as 50 years)is 133.66 tC/ha

When the carbon sequestration was calculated by the mean carbon storage in different age classes the results obtained were: age class 1 to 10 years = 1.1 tC/haLyr, age class 11 to 20 years = 64.7 tC/halyr, age class 21 to 30 years = 322.2 tC/ha/yr, age class 31 to 40 years = 466.4 tC/halyr, age class 41 to 50 yeras = 52.2 tC/ha/yr.

According to the data obtained the current storage of carbon in the state owned teak plantations is 1.66 x 105 kt and the teak trees sequester carbon in the growing ages 0 years to 49 years.

In conclusion, teak plantations up to 49 years can be effectively used as sinks for carbon storage


W. M. P. Gunathilaka1 S. C. Wijeyratne2
Central Environmental Authority Department of Botany University of Sri Jayewardenepura

Investigated densities of bacterial populations in relation to the environmental prameters in Bolgoda North Lake for a period of six months from January to June 2000.

Surface water samples were collected from six sampling stations in the lake at monthly intervals. Densities of bacterial population (total viable colony count), total coliforms and faecal coliforms were enumerated as biological indicators in all the samples collected. Temperature, pH, electrical conductivity, salinity, sechi disk depth, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), Orthophosphate and nitrate contents were measured as environmental (physical-chemical) parameters. Examined correlation among biological indicators and some selected water quality parameters.

High densities of bacterial populations were found in water samples collected from sampling stations at the extreme upper part of the North Lake near out-lets of drains which bring domestic, urban and industrial (textile) effluents. Low densities of bacterial populations were reported from sampling stations at the lower part of the North Lake.

Results revealed that some chemical parameters have an influence on the density of bacterial population. The density of bacterial population showed a significant positive correlation with biochemical oxygen demand and phosphate concentration, while a significant negative correlation with dissolved oxygen content of the surface water of the lake. However, the density of bacterial population did not show a significant correlation with nitrate content.

The density of bacterial population is an useful biolocial indicator for monitoring of organic pollution in inland surface waters since high DO, BOD values and high PO4 -3 content indicate organic and nutrient pollution parameters of surface water quality.


K. I. A. Kularatne1 K. K. R. Mahanama2
1Department of Forestry and Environmental Science
University of Sri Jayewardenepura
2Department of Chemistry University of Colombo

Sulfur compounds, primarily in the form of sulfides (S2- ), sulfites (S032-) and sulfates (S04 2-) have been neglected but has a strong effect upon water quality. The dark colour sediments and strong unpleasant ordours often indicate the S2-contamination in aquatic bodies. To the best of our knowledge, no attempt has been made to investigate these compounds and to asses their contribution to the degradation of water quality. Both the bacteria and dissolved oxygen (DO) are playing leading roles in determining the fate of S containing compounds in aquatic systems.

In this investigation it was intended to study the possible relationships between sulfur species and DO. Four urban stagnant water bodies effected by improper sewage disposal, industrial waste, wet and dry deposition of atmospheric SO4 2-were investigated along with a prawn farm and two coconut husk soaking pits inherited with S compounds. These water bodies indicated the emission of volatile S compounds. These water bodies indicated the emission of volatile S compounds from their characteristic rotten egg smell.

Under this study S2-, S03-2and S042- levels were monitored along with DO, pH and temperature to investigate the possible correlation method introduced by Pawlak and Pawlak (1999) was employed in determination of S2- levels while all other parameters were measured by employing standard methods.

Based on the results obtained, only S2- shows a significant correlation with DO under ambient conditions. Finally, measured dissolved S'- levels were utilized to determine the possible H2S emission levels. Calculations have shown that each of the water body is emitting gaseous H2S and in most cases, emission levels are greater than the ordour thresholds accounting for the unpleasant smell near these stagnant water bodies.

*Correspondence author


J. P. Padmasiri.
National Water Supply And Drainage Board, Peradeniya

In recent studies (1994-2000) it was shown that more than forty percent of wells has fluoride rich water in the North Central Province. The fluoride content of more than 1 mg/1 was considered as fluoride rich water. The dental fluorosis had been identified as an endemic problem in dry zone areas in Sri Lanka. the unsightly brown discoloration of the teeth had led these young children affected in villages to a severe psychological impact. This problems is not confined only to Sri Lanka but also exists in other parts of the world such as India, China, South Africa, America. In addition, medical reports revealed that skeletal fluorosis patients has been identified in Kekirawa, Medirigiriya, and Jayanthipura in Sri Lanka.

Defluridation of water could be done by different filter media such as serpentine, activated alumina, alum, charred bone meal. However, the main disadvantage of such material is that they are not locally available. This paper discusses results of a programme which introduced a low-cost defluoridator which uses freshly burnt bricks as the filter media to affected communities in the North Central Province.

Awareness programmes were conducted for students in schools, health staff, pre-school teachers, Grama Niladharis and Samurdhi Niyamakas in villages in North Central Province. There after 1000 defluoridators were distributed in stages (1994-2000) and they are in operation in different villages such as Olukarada, Maha Elgamuwa, Madatugama, Eppawela, Galnewa, Thalawa, Thapotha, Athumalpitiya and Patunagama in North Central Province.

The results clearly show that this low cost method could be easily carried out in order to get defluoridated water. The beneficiaries themselves were trained to change the filter medium in time in order to get best output from these defluoridatos. The efficiency level of these defluoridators changes from 85% removal of fluoride at the start and tapers down to 25% removal at the end of the cycle


Nilanthi Bandara
Department of Forestry and Environmental Science,
University of Sri Jayewardenepura

Solid waster management is a major environmental problem faced by developing countries at present. At present the most common waste disposal option in developing countries is the open dumping of waste. The reasons for the non-adoption of sanitary landfilling in developing countries are many, the main amongst them being the lack of an adequate financial base for the process.

Review of literature shows that the failure or reluctance to implement sanitary landfilling as a waste disposal option in developing countries is also because the landfill technologies available at present due to many factors cannot be successfully transferred to developing countries. However, many new cost-effective approaches have been developed which could be adopted in these countries.

This paper reviews considerations in planning designing and operation of sanitary landfills in a developing country. These considerations include the basic differences between the waste management scenarios in developing and developed countries; constraints faced by developing countries to implement a cost-effective waste disposal plan; policy consideration; siting of landfills taking advantages of the natural aspects; minimal requirements for landfills according to a classification system; appropriate designing to control leachate and landfill gas emissions and treatment of leachate and operation and maintenance of landfills taking into consideration unique factors such as scavenging activities and availability of manual labor.


D.C. Kaluthota1 K. K. D. S. Ranaweera1 D. M. S. H. K. Ranasinghe2
Faculty of Applied Sciences University of Sabaragamuwa Department of Forestry and Environmental Science,University of Sri Jayewardenepura

Diplerocarpus zeylanicus, an endemic tree in Sri Lanka offers great potential for bridging the gap between supply and demand of timber in the country. However, at present it has not been widely used as a plantation species. Establishment of plantation by seeds has proved somewhat difficult due to low viability etc. Genetically uniform planting stock can be obtained rapidly through vegetative propagation.

With the above objective in mind an experiment was conducted to propagate stem cuttings of D.zeylanicus using a variety of rooting hormones under both mist and non-mist conditions. In all the instances, cuttings of 15 cm length and 0.3-0.4 mm basal diameter with two and half leaves were used. The hormone concentrations used were, Indole Butyic Acid (IBA) 500 ppm, 1000 ppm and 1500 ppm and the commercial hormone Sector (NAA + fungicide). Control did not have any hormone treatment. The medium used was sand. The experiment was conducted under two conditional environments; under a automatic mist and in a non-mist polypropagator, a low cost alternative which was also designed to maintain a high humidity through water manipulation.

After the experimental period of 10 weeks, there was a marked difference between the mist and non-mist conditions in percentage survival of cuttings. In all the treatments, % survival was higher under mist. In terms of percentage rooting, the cuttings under the non-mist propagator did not show rooting at all although callusing was observed in all the treatments at varying success levels. Among the rooting treatments, the highest percentage rooting (38.10%) was shown in the control without rooting hormones closely followed by other hormone treatments. However, the treatment 1000 ppm of 1BA showed the lowest percentage rooting (11.11%).

From these results, it can be concluded that D. Zeylanicus can be effectively propagated by stem cuttings under mist conditions.


J. Hettiarachchi D. M. S. H. K. Ranasinghe
Department of Forestry and Environmental Science,University of Sri Jayewardenepura

Forests provide numerous benefits other than timber and fuelwood and these are called non-wood forest products. They play a vital role especially in the rural economy and provide benefits of considerable importance at the national level. Despite an escalating demand, these non wood forest products do not enter markets directly due to the absence of proper marketing channels. This discourage primary collectors, do not warrant for sustainable collection of the produce in the wild and the possible planting of the resources.

This study was conducted to assess the current market situation for non-wood forest products with special reference to medicinal plants and cane with a view to make recommendations for the improvement of the marketing situation in this regard.

Data were collected from plant collectors, small scale regional buyers and wholesale dealers by way of questionnaires and interviews. To collect information on medicinal plants 4 areas where medicinal plants are very much abundant were selected, viz. Ritigala (Anuradhapura District), Rajawakaa (Ratnapura District), Kanneliya (Galle District) and Bibile (Moneragala District). With regard to Cane, the most abundant areas; Manampitiya (Polonnaruwa District) and Baduraliya (Kalutara District) were selected. Further, data were also collected from wholesale dealers of medicinal plants at Gabo's Lane and ayurvedic product manufacturers. With regard to cane, product manufacturers at Radawadunna were interviewed. Secondary data were collected from institutions.

The results revealed that both medicinal plants and cane are being collected in a unsustainable manner. As the existing marketing situation is disorganised, the middle man is benefited most while the collectors do not reap much benefit for their labour. Majority of the crude medicinal plant materials are still imported while there is very low value addition to the material that is exported. Most of the raw cane too is imported. The cane available in the country do not fetch a good demand as it is considered as low quality. Most of the people engaged in these businesses do not use the facilities offered by the banks very much possibly through unawareness.

The following recommendations emanated from the study to improve the marketing situation with regard to the above industries in the country; introduction of sustainable methods of collection, planting of the produce in country as large medium scale plantations, improving the quality of products and value addition and making the people more aware for the facilities provided by financial organizations to improve the industries


1W. A. J. M. De Costa 2A. G. Chandrapala
Department of Crop Science, Faculty of Agriculture,University of Peradeniya.
Natural Resource Management Centre, Faculty of Agriculture, University of Peradeniya

Contour hedgerow intercropping (HI) is an agroforestry system recommended to improve soil fertility and sustain annual crop yields on the steep lands of humid central highlands of Sri Lanka. The objective of the present experiment was to quantify the overall tree-crop interaction (TCI) by partitioning the positive fertility effect (F) and the negative competition effect (C) of Gliricidia sepium hedgerows on maize (Zea mays L.) grown in a HI system on a sloping (35%) land at Peradeniya in the mid-elevational (479 m above sea level), humid (rainfall of 2000 mm/yr) zone of Sri Lanka. The experimental treatment structure consisted of two hedgerow intercrops with (H m) and without (Ho) tree prunings added as mulch and two sole maize crops with (Cm) and without (CJ mulch. The highest maize yields were obtained in Cm whereas C and Ho had the lowest with no significant difference between them. Hm had an intermediate yield. The overall TO was positive (ranging from 26 to 112% depending on the method of estimation of C) because of substantially positive F (85 to 94%) which outweighed the predominantly negative C (-67 to +18). Mulching increased the availability of P and K to maize and increased soil pH. Mulching also decreased soil N and K and increased soil P during the cropping season. There was significant competition for light by hedges, especially near the hedgerows. Howeyer, positive effects of mulching ensured greater crop growth and radiation interception away from hedges. Soil water (SW) depletion from top layers (0-30 cm) was highest in Ho. Within mulched treatments, Hm showed lower SW depletion that Cm during the first 10 weeks showing the shading effect of hedges. However subsequently, Hm had greater SW depletion than Cm indicating greater SW extraction which was confirmed by SW depletion in deeper (30-110 cm) layers. Based on inter-treatment variation of nutrients, water and radiation, it is concluded that in the present situation, the fertility effect of hedgerow prunings exceeded the competition effects of hedges.


G. A. D. Perera
Department of Botany,University of Peradeniya

The forest regeneration immediately after traditional shifting cultivation was studied in an abandoned shifting cultivation field at Sigiriya in the northern dry zone of Sri Lanka. Biotic and abiotic factors that are responsible for the forest regeneration process were also identified.

The vegetation and the soil seed bank (both surface and sub-surface) were enumerated before clearing the land for shifting cultivation and one month after the abandonment. In addition, the soil seed bank was investigated 15 hours after burning of the land (i.e. a 12-15 year old secondary forest) prior to cultivation. Some physical environmental parameters were recorded after the abandonment of the land.

Regeneration after traditional shifting cultivation was mainly by roots and stem bases of woody plants, which existed before cultivation. Thus, many early and late survivalspecies were regenerated. The ground of recently abandoned shifting cultivation land was very open (% canopy opennes = 69.39±4.80 and this results in to have high soil temperatures and low soil moisture contents. Wind dispersed seeds of grass and agricultural weed species frequently disperse into the burnt land. Few seeds of some pioneer species are capable of withstanding fire and may occur as a soil seed store. However, seeds in the soil seed bank may not involve in forest regeneration at this early stage. Underlying reasons for that are also discussed.


1C. Gangodagama 2S. P. Aggrawal
1Arthur C Clarke Institute for Modern Technologies
2Indian Institute of Remote-sensing

A Hydrological model was developed for the Bata River basin, which is one of the tributaries of the Yamuna River, Infiltration and losses, unit hydrograph and river routing are the main model components. ILWIS and Auto CAD software were used to hydrological modeling. Satellite Remote Sensing and GIS techniques were used to estimate the relevant spatial parameters, which are used as input to the hydrological model. SOI topomap, data collected from the field work, IRS LISS-111 temporal satellite data for rabi and kharif seasons and IRS PAN data are used as input for the model. SCS curve number method is used for the infiltration losses and synthesis of unit hydrographs. Complete watershed is divided to 10 subareas. Ten hydrographs were developed as one for each subareas. Characteristics of the watershed were evaluated by modeling the watershed as a whole as well as subarea basis by routing the unit hydrographs along the river reach. Muskinguna hydrologica routing method is used for river routing. The constructed model is capable of forecasting the runoff for the particular event of rainfall and derives hydrographs for required time duration


M.G. Mohamed Thariq1 Hiran S Amarasekara2
1 Sri Lanka Forestry Institute, Nuwara Eliya. 2Department of Forestry and Environmental Science
University of Sri Jayewardenepura

The present study was carried out to investigate the standards of the imported sawn wood found in building construction and furniture manufacturing sits, and among timber dealers. A questionnaire survey was carried out in the districts of Colombo, Kandy and NuwaraEliya and the collected timber samples from the users and from the timber dealers were examined.

The investigations revealed that the imported hardwoods such as Kempas, Tulang, Bitis, Durian, Tembusu, Burma Teak and some other unidentified species are found in the construction and furniture manufacturing sits and in the market. Results show that authentic Balau or Red Balau were not received by the users or supplied by the timber dealers. Only 42% and all 100% of the users received authentic Kempas and Tulang respectively, whereas 42% and 50% of the suppliers sold authentic Kempas and Tulang respectively.

The density of the unidentified hardwoods received by users as Kempas were found to be comparable to Kempas except one species, which was inferior to Kempas. The unidentified hardwoods received as Balau and Red Balau were found to be medium or heavy hardwoods based on their density. The density of the unidentified timbers that are sold as Kempas was comparable to Kempas. The unidentified hardwoods sold as Balau, Red Balau, Bitis and Kandis were medium or heavy harwoods based on density determined. Most of the imported harwoods found in the construction and furniture manufacturing sites and in the market had acceptable quality based on the density, but durability of the unidentified hardwoods was not known for the comparison. Based on results it was found that some for the species supplied by the dealers as high rated timbers, (e.g. Durian) had comparable density values with that of true species (e.g. Balau and Kempas) but these species were less durable compared with the true species. Based on the findings of the present study, it is suggested to develop practicable standards and quality assurance methods for the imported hardwoods.


A Dissanayaka
Regional Economic and Agricultural Project, Matale

Limestone related industries in Sri Lanka have a history of 2500 years. The major cultural and Buddhist shrines in ancient Sri Lanka has some of extraordinary paintings and sculptures carved out from limestone marble and mixture of paints.

The paper reviews a people initiated, locally managed and environmentally friendly crystalline limestone industry popularly named as 'Matale Aluhunu'. Limestones are used to produce lime in the building industry, fertiliser or soil conditioners depending on the composition. Marble chips are used in terrazzo industry. There are 3 major types of lime industries; lime kiln, dolomite and lime query. Total number of industries is 177 of which more than 50% are small scale. The cost of production of such small scale lime industry to produce 1 ton is around Rs. 6500 and the income is around Rs. 7800.

Lime Industries Association in Matale is an organisation which was established about a decade ago to protect small industrialists from middlemen exploitations and price fluctuations in the market. Further it was also established with the intention of protecting the natural mineral beds (limestone and dolomite etc.) in the district. There are about 1500 direct beneficiaries and 200 indirect beneficiaries who receive a modest annual income to maintain their families. The salient aspect of this lime industry maintained by this local organisation is its commitment to fulfill all the environmental and safety conditions set by the governm6nt. They have all the necessary permits; environmental safety assurance permit, trade license, local administrative permit, geological license, explosive permit and the security permit.

This paper reviews the issues that need to be addressed to develop this rural people initiated industry further, market and quality improvement support to expand the industry as a large scale enterprenuship, attract capital investments from outside, research on production of lime for better environmental sustainability, exploring the possibility of developing ecological tourism around this industry etc.


T. Serasinghe K. K. Pathirana
Department of Animal Science Faculty of Agriculture
University of Ruhuna

A long term (6 year) grazing experiment was conducted in a coconut plantation at Hakmana, a farming village in the southern Sri Lanka, to observe the impact of grazing on botanical composition of natural herbage and soil characteristics. The treatments were ungrazed coconut land (UG), continous grazing of natural herbage under coconut with out straw (G), G + rice straw adlibitum (GS) and GS + supplements (GSS), with a density of 3 animals/ha in all the treatments.

The changes in botanical composition at the end of the six-year period indicated that herbs were dominant in the UG treatment, with an increase of the production of herbage with time, Euphatorium odoratun, Veronica cinera and Cyperus kyllingia were the most dominant species. The highest decrease in herbage production were seen in animals that were not given straw (G) and the decline worsened with time indicating overgrazing and soil erosion. In contrast the initial decline in herbage yields gradually increased in GSS indicating a possibility of a stocking rate greater than 3 animals/ha, considering the subjective observations of the ground cover in paddocks as well. Due to the changes in grazing pressure, the percentage of prostate grass species (Axonopus compressus, axoopus affinis etc.) and leguminous species (Desmodium spp.) improved the ground cover in GS through GSS. Hence straw and more significantly supplemented straw feeding improved botanical composition and animal production per unit area while increasing the potential for soil conservation.

Treatments had no significant effect on the soil bulk density up to the end of 6 years and the water holding capacity up to the end of 3 years. By the end of 6 years grazing cattle significantly increased the water holding capacity of the soil from G through GS to GSS. Low inputs of resources available to farmers have thus produced increasing benefits with the passage of time and demonstrated the potentials for the sustainability of a crop livestock integrated system.


T. Jayasingham
Department of Botany Eastern University

Alluvial soil spread over the coastal belt of the Batticaloa district in the Eastern Province while the red earth take over the interior, west of the lagoon. More that 80% of the districrt uses firewood as their primary energy source and the stock have dwindled over the past with much destruction of the natural and other forest resources, including home gardens. A clear need for cheap energy source is an urgent need into the future. Casuarina equisetifolia has been found to grow very well under all soil types of this district and is also a species known for its high energy content. This study was designed to study its potential as a firewood crop and the cost effectiveness as an energy source. An ideal crop should grow fast, be energy rich and coppice well for steady supply following a harvest and also occupy a relatively little space.

Six plots of 20 x 20 m each were planted with 6 month old saplings, grown in our own nursery, at a rate of 10,000 plants per hectare having 400 plant per plot. Plants were watered daily for three months and every other day for the next four months. Height of the plants were recorded from the first month every three months and the diameter was record after a year. Mortality was recorded from planting and the dead plants were replaced from the stock until a year after planting. Harvesting of wood resources was carried out in various ways: Pruning of all branches below 3' as done after 12 months; Pollarding was carried out by cutting the main branch above 6' in 7 rows of 2 plots in 18 months; Total shoot harvest was done in 14 rows in 2 plots after 18 months; Pruning of all branches below`6' was carried out after 2 years and total harvest was carried out at random after 27 months. I each case fresh/drywt of the product was recorded. Coppicing also was recorded after pollarding and total harvest.

30,884 kg of wood would be harvested per hectare after three years. 60% of harvested plants would coppice. Only 7078 kg would be harvested in two year period. Non destructive harvesting (pruning, pollarding) would yield around 10,000kg per year. The revenue may be calculated at Rs.2 per kg of firewood. The cost of this project is around Rs. 125,000 with Rs.90,000 towards labour. Perhaps, the cost could be reduced by adjusting the planting season and also having the plants in larger bags for a longer period before planting.

The project may be translated to a family which provides labour as a means, towards an earning of a conservative estimate of Rs.1,500 per month from one hectare plantation, the minimum as the return over the further years are more positive. The data on cost from Ceylon Tobacco Company is Rs.36,800 per hectare of for a firewood plantation of eight years.

The potential of such plantations in Biomass energy production is also important. It is stated that 1 d hectare plantation would produce a 1 Mw power sustainably. The species does flags high as a potential where marginal lands are available in plenty, having also in mind its ability to fix nitrogen. It would be an ideal species and project for a family based income in the future


N. F. Perera E. R. K. Perera
Department of Animal Science Faculty of Agriculture
University of Peradeniya

Time to time many plant species has been introduced to Sri Lanka either intentionally or accidentally. Their existence, dispersion and naturalization persisted unnoticed. However, with the present interest on biodiversity it was realized that some of these species are posing a threat to the existence of many other native species. In recent studies, about 20 of such species have been identified as invasive in nature and many concerns has been directed on them. Presently, some of these species are economically important and widely used.

For example, Tithonia diversifolia (wild sunflower) Panicum maximum (guinea grass), Pennisetum clandestinum (kikin grass) Prosopis juliflora, Lantana camara, Eichchornia crassipes (water hyacinth) and Myroxylon balsamum (Kattakumanchal) provide multiple uses such as cattle feed, fodder, green manure, biopesticides and phyto extractants.
Similarly Mimosa pigra and Parthenium may have economical values not yet investigated and exploited. Therefore, the most appropriate and intelligent way of handling these so called invasive species is to identify and exploit their full economic potential and to investigate as to why they have reached the invasive status. However, further investigations would be necessary in any attempt to commerciable such products.


S. M. C. U. P. Subasinghe T. A. R. Jenkins G. J. Mayhead
Department of Forestry and Environmental Science
University of Sri Jayewardenepura
School of Agricultural and Forest Sciences, university of Wales Bangor, UK

A growth model to predict the future diameter at breast height of Corsican pine trees was constructed using easily measurable explanatory variables. For this work it was assumed that future growth of individual tree diameter at breastheight ( dbht +At ) can be predicted as a function of current dbh (dUh,), currentage (a,), age at the time prediction is required ( at+4t ), current stand density (d) and quality of the site (s) as in the equation 1.

dbht+ot = f (dbk, at, at+ ot, dt, S)

Repeated measurement data of permanent sample sample plots over a long period were obtained from the Forestry Commission in Great Britain. These plots were maintained under two thinning types i.e. intermediate and neutral. First the data were divided by the thinning type and each thinning type was divided by the thinning type and each thinning type was divided again as working (3/4) and validating (1/4) data.

In order to reduce the number of variables, the time difference between the beginning and end of the simulation period (ad.~ was used for the age factor. Fourfactors i.e., top height, top height/age, total basal area/age and top height/total basal area were used to represent the site quality. Suitable transformations were2used for all the cadidate variables in order to obtain the best medel. R , residual distribution, average model bias, mean absolute difference and modelling efficiency were tested for the evaluation purpose.
When tested, stand density was not significant and the best site factor was the total basal area/age. The finally selected equations were as below.Intermediate thinning:

dbh2+pt =1.014 dbht + 0.059site + 0.004ad1 f
Neutral thinning:
dbhr+ot =1.050 dbht - 0.059site + O.OOSadI f

When there is little difference in age, ad;f ---) 0 and site factor can be ignored because it dies not change when age difference is zero. In such a situation,
dbht+ot =dbht
and therefore the parameter associated with dbht must not be significantly different from one. However, this condition was not fulfilled by above models and a new set of parameters were estimated forcing that parameter to be one. The test results for the models with new parameters indicated that there was no bias and the modelling efficiency was 0.99 for both thinning types. The validation procedure indicated that the models were adequate. The final models are given in equation 4 and 5.
Intermediate thinning;
Neutral thining;
However, when tested, it was not possible to use one set of common parameters for both thinning types.


A. N. Jayakody
Department of soil Science Faculty of Agriculture
University of Peradeniya

Well water could be loaded with plant nutrients by over applications of fertilisers and manure. This could be perilous to the environment. Over applications of fertilisers and manure are very common in hill-country vegetable cropping systems of Sri Lanka.

In this study, major plant nutrient levels in 7 wells along a soil catena in Pattipola under intensive vegetable cultivation were monitored. A well in the forest of upper catena was selected in the control.

Water was sampled in weekly intervals for 3 months. pH of those was measured in -situ. K, Ca, Mg, PO4, P, NH4-N and N03-N were determined in preserved samples. A quantification of the nutrients recycled through irrigation issues was also done.

pH-values of water in the cultivated segments were in moderately acidic range of 4.4 - 4.9 compared to 5.2 of the control. Ca, P04-P and NH4-N levels were low in par with the correct due to the considerable adsorption by the soil.

However, K, Mg and N03-N levels were contrastingly higher that that of the control indicating the influence of fertiliser and manure applied. Some wells of the lower slope showed > 28 ppm N03-N compared to 2 ppm of the control.

4, 9, 1.5, 2 and 20 kg/ha of Ca, Mg, P04-P and N were brought back to crops through an average irrigation issue showing a mild similarity to a foliar fertiliser applications.


Aruna Kumara, R.Senarathna U. Wickramasinghe
Department of Crop Science,Faculty of Agriculture, University of Ruhuna

The study involved characterization of physical. chemical, and biological properties of a severely disturbed soil in Kamburupitiya, which has been previously maintained under agroforestry.

The bulk density, true density, and porosity of the soil were 1.163 gcm3, 2.14 gcm3 and 45.6% respectively, with a water holding capacity of 28.5%. The per cent organic matter and N in the soil were 0.451 and 0.0088, respectively, whereas the corresponding values in an undisturbed neighboring site, were 1,214 and and 0.095. The cation exchange capacity of the degraded soil was 4.71 m.e. per 1~OOg. of soil and had a H value of 4.2. The corresponding figures for the reference site were 7.4 and 5.43, respectively. Biological activity of the soil as measured by soil respirometry, amounted to 0.716 mg COZ/1000g of soil/hr and 1.355 mg CO-,/1000g. of soil/hr in disturbed and undisturbed soil, respectively. No macro fauna was evident in the soil. Even after 12 years of disturbance, soil regeneration was extremely slow, thus agronomic interventions prove important to accelerate the soil restoration process

Tuesday, October 31, 2006


K. K. I. U. Aruna Kumara U. Wickramasinghe R. Senarathne
Department of Crop Science Faculty of Agriculture University of Ruhuna

An experiment was conducted, during March-July 2000,at the Faulty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, to study of the effect of levels of salinity on seed germination of three salt tolerant species, namely Acacia leucoploea (Katu Andara), Parkinsonia aculeate (Parkinsonia) and Cassia auriculate (Ranavara)

The experimental design used, was Randomized Complete Block Design with 5 treatment and 4 replications. Here, sea water (40 ds/m) was diluted to give varying salinity levels (i.e. 2, 4, 8, and 12 ds/m) and normal water (0.13 ds/m) was used as the control. Saline solutions were applied to seeds and the rate and percentage germination was observed.

The results obtained from the experiment showed that, low salinity levels (4 ds/m) increased seed germination of all 3 species. But with increasing salinity beyond 8 ds/m a decreasing in germination was observed. When the salinity level was 8 ds/m, the percentage of germination in Katu Andara, Parkinsonia and Ranavara about 40, 40 and 13 respectively.

The percentage of germination in Ranavara was 0 at the salinity level of 12 ds/m. But in Katu Andara and Parkinsonia, 23% and 15% germination was observed at 12 ds/m. Thus, these species can be ranked in oder of tolerance to salinity as follows:
Katu Andara > Parkinsonia > Ranavara


K. A. Nandasena
Department of soil Science Faculty of Agriculture
University of Peradeniya

Total Nitrogen content in tropical soils ierally low compared to the most temperate soils. About 98% total nitrogen is associated with soil organic matter which in turn subjects to mineralization and hence releases mineral nitrogen to the soil. Thereby most tropical soils nitrogen supplying capacity or nitrogen mineralization potential is relatively low and declines rapidly during cropping season unless nitrogen sources are incorporated frequently. This investigation conducted to find out the nitrogen status, distribution of different nitrogen fractions and the mineralization potential of some selected agriculturally important soils of Sri Lanka.

Sixteen soils collected from various locations representing different soil types were analysed for total nitrogen. Eight soils from sixteen soils were fractionated and analysed for different nitrogen forms viz; available N, ammonia-N, amino sugar-N, amino acid-N, acid hydrolyzable unknown N and acid insoluble-N after acid hydrolysis. In a laboratory incubation experiment, those eight soils were subjected to follow the nitrogen mineralization potential and to determine the mineralization rates according to the method described by Stanford and Smith (1972). The nitrogen mineralization data during 315 days of inclubation were used in Stanford and Smith's first order decay model to calculate nitrogen mineralization rate(k) and nitrogen mineralization potential (No).

Total nitrogen contents in the studied soils varied from 89.36 (Aralaganwila) to 365 mg/100 g soil (NuwaraEliya). Soil organic matter contents also gave similar variation and showed close relationship with total soil nitrogen. The distribution of different forms of soil nitrogen also varied among the soils studied. A major part of organic nitrogen in Sri Lankan soils was found to be associated with amino acid-N fraction followed by the ammonia-N fraction. This was consistent with the other studies conducted in elsewhere (Stevenson, 1957; 1982)Nitrogen mineralization rate was ranged from 0.0069 to 0.026 N mg/100 soil per day. Highest mineralization rate was given by two paddy soils (Kiribathkumbura and Pilimathalawa).

Nitrogen mineralizations potential or nitrogen supplying power also varied from 5.33 to 38.52 N mg/100 g soil. High mineralization potential was also recorded in paddy soils. This may be attributed to the high organic matter contents in those soils. Further these different nitrogen supplying powers of soils reflect their inherit characteristics or potential in supplying available nitrogen for plant usage. One should give serious consideration to those parameters of soil nitrogen when nitrogen fertilizer recommendation practices are conducted for crops to attain optimum yield.


K. A. Nandasena and R.P.U.G. Balasooriya
Department of soil Science Faculty of Agriculture
University of Peradeniya

Use of organic manures as a nutrient Source for crops is common practice in agriculture. Added advantages of using organic manures against synthetic fertilisers are the positive influence on physico-chemical and biological characteristics of soils. Release of mineral nitrogen from organic manures could be used as an index to check the quality of organic manures in relation to nutrient supply to the crops. Therefore, the objective of the present laboratory leaching study was to monitor the nitrogen release from soils after addition of selected organic manures.

Two surface soils, Reddish Brown Earths and Non Calcic Brown (0-30cm) collected from Mahallluppallama and Aralaganwila areas respectively, were used in this study. Soils were mixed with three organic manures; Poultry manure (PM), Glyricidia leaves (GM) arid Rice straw (RS) at the rate of 20 and 40 tons/ha. There were four treatments; 1). Soil only - control, 2). Soi1+PM. 3). Soil +GM and 4). Soil + RS. Each soil-organic manure mixture was placed in leaching columns and incubated in dark at room temperature. Mineralised nitrogen (NH+4 - N and N03 -N) was extracted with 0.01M CaCIZ solution at 7, 14, 21, 35 and 49 days after incubation using the method described by Stanford and Smith (1972). The NH+4 -N and NO3 - N contents were determined by using standard Kjeldhal method. The physico-chemical and nutritive characteristics of soils and organic manures were determined bv using standard laboratory methods. Results of the study revealed that the application of organic manures has pronounced effect on the release of nitrogen. In both soils, 40 tons/ha level showed higher release of nitrogen compared to 20 tons/ha level. Out of three organic manures, PM treated soils showed a higher release of nitrogen followed by GM treated soils. The RS treatment showed a very low release of nitrogen which is caused by the immobiolisation in two soils during the incubation. It was very clear that the release and immobilisation of nitrogen are controlled by theC/N ratios of organic manure. Up to 7`h day the nitrogen release from PM and GM treated soils was high against the control as well as RS treated soils. After 7`h to 21`h day, the mineralisation and release of nitrogen was decreased and subsequently it was increased up to 35`h day and then again decreased at the end of incubation with few exceptions. In general, the proportion of NH+4 -N to N03 - N was high at the early stage of the incubation compared to the latter stage of incubation. This may be attributed to the transformation of more NH+4 - N to N03 -N by the nitrification process operating at the higher rate at the latter stage of incubation. The release of NH -N and NO -N from organic manures was significantly higher than the control at certain sampling times. However, according to this study, the use of organic manures such as PM and GM with C/N ratios will enhance the mineral nitrogen content in soils during the first week of incorporation


Rizana M Mahroof1 Jayanthi P Edirisinghe1 Caroline Hauxwall2
1Department of Zoology, Faculty of Science
University of Peradeniya
2Institute of Ecology and Resource Management
University of Edinburgh

The main factor limiting cultivation of mahogany, Swletenia macrophylla King (Meliaceae), in plantations is damage by shoot borers (Hypsloyla spp.). Shade has been repeatedly cited as reducing shoot borer attack but the responsible mechanisms have not been determined by experimentation. Shade may alter either secondary compounds such as limonoids or nitrogen concentrations or both in the plants making them unsuitable for insect survival and development. Previous studies have not examined whether shade influences limonoid and nitrogen content of S.marcrophylla and thereby alter shoot-borer attack. Therefore, these studies were designed to identify the variation in incidence of shoot borer attack under three levels of shade treatments in the field conditions and the variation in plant chemistry of S.marcrophylla shoots grown under three different artificial shade treatments. The hypotheses tested were under high light availability (i) incidence of shoot borer attack increases (ii) the concentration of limonoids present in the shoots of S. macrophylla decreases ind(iii) total nitrogen content of shoots increases.

This study was done from 1997-99 in Sri Lanka and UK. Attack by the shoot borer was assessed 54 weeks after planting. The Limonoid content was investigated by Thin Layer Chromatography (TLC) and the total nitrogen by Kjeldhl method using freeze-dried ppowdered shoots. The incidence of shoot borer attack was significantly higher under low shaade (d.f.=2, F=8.6, p=0.0003). The intensity of the green-blue fluerescence under UV seen in the TLC plates was greater using the extracts from the high shade treatment compared to that from the low shade treatment. The total nitgrogent content was satistically lower in the high shade (1.114± 0.22%, n=33) compared to that in full light (1.36± 0.22%; n=31). These results suggest that light environment may have a significant effect on the concentrations of limonoids and nitrogen in S.macrophylla which in turn influences the shoot borer attack.

The study forms part of a larger project on 'Silvicultural prescription for mahogany plantation establishment; Research grant funded by DFID, UK is greatfully acknowledged


K. K. I. U. Aruna Kumara U. Wickramasinghe G. A. Dayathilaka R. Senarathne
Department of crop science, facuiry of Agriculture, university of Ruhuna

Macaranga peltata is one of the most widely occurring early successional woody species, specially in low country wet zone. Although Macaranga spreads profusely by seeds, the seed biology and germination behavior has not been studied. According to the preliminary studies, it was revealed that, the germinability of freshly isolated seeds is very low. Therefore this work was undertaken to understand the germination behavior and measures to enhance seed germination of Macaranga. The study was conducted during May-July, 2000, at the faculty of Agriculture, University of Ruhuna, Mapalana, kamburupitiya, Sri Lanka.

Three treatments used, i.e. mechanical scarification using sand papers (T,), Chemical scarification using HZSO4 acid (Tz) and hormone treatment using GA (T3), with the control. Fully ripened seeds were harvested and thoroughly washed to remove the peel and air-dried for one day. Dried seeds were treated as indicated above and placed in petri dishes containing sand media and allowed to germinate. Three replications were used for each treatment and percentage of germination was recorded at 7,14,21 and 28 days after planting.

Germination of Macaranga seeds started after 14-21 days in control by after seven days in treated seeds. Mechanical and chemical scarifications were not effecting in increasing the percentage of germination significantly. But the gibberelic acid treatment has made a tremendous important in the percentage of germination and at the same time resulted in significant reduction it time taken for germination. Although scarification treatments may have improved permeability of seed coat, it has not contributed to the germinability of seeds, the significant impact made by GA treatment both in increasing and accelerating the germination probably reveals that there exists a dormancy in Macaranga seeds which is of physiological or metabolic in nature GA treatment of more effectively at higher concentration: (20mm) was capable of breaking the dormancy and thus enhanced germination.

Keywords: Macaranga peltata, Seed germination, dormancy, gibberalic acid_


1E. P. S. K. Ediriweera 1B. M. P. Singhekumara 2P. M. S. Ashton
1Department of Forestry and Environmental Science, Univer sity of Sri Jayewardenepura
2School of Forestry and Environmental Studies, Yale University, New Heven, U.S.A.

Growth performance of seedlings belong to nine late-successesional canopy tree species was studied at three different topographic positions (ridgetop, midslope and valley) in the Sinharaju rain forest, southwest Sri Lanka. Seedlings were planted in plots located in valleys, midslops and ridgetops. In each site four canopy openings and four adjacent understoreys were selected to plant seedlings of nine late-successional canopy tree species. Seedling growth and mortality were monitored for three years.

Results demonstrated that a clear difference in survival and growth among species. These differences appeared to be related to the availability of soil moisture and groundstorey radiation regimes of the forest. Shorea disticha exhibits high growth rate than others in each topographic position in each site. Seedlings of Mesua ferrea and Shorea megistophylla exhibit a higher survival than other species in canopy openings and understorey conditions of all topographic positions. Growth performance and survival of their species will be monitored for several years to study the nich specialization of the late-successional canopy tree seedlings


K. K. I. U. Aruna Kumara U. Wickramasinghe R. Senarathne
Department of Crop Science, Faculty of Agriculture, University of Ruhuna

Restoration of degraded ecosystems has become a matter of great concern. Early successional species play a key roll in the process of restoration. Therefore here a study was undertaken to assess the accumulation and partitioning of biomass and nutrient in widely occurring early successional shrub species, namely 7.izyphus oenoplia (Eraminiya) of varying ages (i.e. 4, 6 and 8 years). The experiment was conducted at the faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya, during March-August, 2000. Here, four plots were selected for each age class and four plants were sampled for each plot and their distribution of dry matter and major nitrient (NPK) in stem, branches and leaves were measured in each plant.

Findings clearly indicate that majority of biomass was concentrated in plant stem and as the age progressed, this proportion is increased. These results further indicate that the biomass allocation to the leaves was high in young ages and it is decreasing as the age progressed. Total biomass of plant after 4, 6 and 8 years was 902, 2602 and 4552 g respectively.

Results also show that major nutrient content in leaves, branches and stem were high in early stages of the growth and decreasing as the age progressed. Percentage of N. P and K in leaves at 4 years were 2.91, 0.116 and 1.54 respectively. But after 8 years N. P and K content were 2.36, 0.093 nd 1.275% respectively, show a decreasing rend of concentration of major nutrient in leaf tissues. Stem and branches show the same pattern of nutrient partitioning as the plant getting matured.


N Wickramaratne
Department of Geography, University of Peradeniya

Serpentine, bearing the general formula: Mg3Si,OS(OH)a denotes a group of hydrous, magnesium silicate minerals. Sri Lanka too, serpentine bodies occur roughly on the boundary of Vijayan and Highland series of rocks. The three principal serpentine areas of Sri Lanka are 'Ginigal-pelessa' and 'Indikola-pelessa' both close to Uda Walawe and, 'Ussangoda' near Nonagama Junction.

Within broad climatic zones, soils developed on serpentine mineral substrates harbor unique vegetation communities. Such communities are referred to as lithobiomes and have attracted scientific attention. Other examples of lithobiomes are vegetation on limestone and saline soils etc., which are interspersed within zonal soils.

Ginigal-pelessa and Indikola-pelessa serpentine bodies are located about three kilometers apart. The area receives a rainfall of about 1325mm/yr and the average number of rainy days per year is 94. The maximum amount of rain comes between October and December.

The objective of the present study was to initiate a survey of vegetation in these two unique areas. The study was initially begun in September 1998 in Ginigal-pelessa and was extended to Indikola-pelessa in 1999. It included reconnaissance of the two areas followed by a survey of plant species and soil. Woody plant species were studied in 10 x lOm quadrats whereas, grasses and herbaceous plants were examined in 1 x lm quadrats. Density of the grass vegetation and the abundance of woody plants along with girth were recorded. Slope of the areas was measured with an Abney level. Also examined in each area was a shallow soil pit and soil depth was measured in selected points, by means of an auger. Soil color was determined with the aid of a color chart, yet no soil chemical analyses were done.

In Ginigal-pelessa the maximum slope is 15% and it is 12% in Indikola-pelessa. The substrate in both places is an undifferentiated soil developed from serpentine minerals. It is shallow (<45cm in Ginigal-pelessa and <42cm in Indikola-pelessa) and overlies partly weathered serpentinite rocks. The color varies from 7.5 3/2 YR-wet. It is friable (dry) and very friable (wet). It is a silty loam, which is slightly sticky, and slightly plastic when wet. Reddish Brown Earth (RBE) Surrounds the two areas, where the terrain is slightly undulating. The aggregate extent of the two areas is more than four kmZ. Yet, only a few hectares of the associated vegetation remain fairly inact in Ginigal-pelessa whereas, almost the entire serpentine vegetation has been drastically changed in Indikola-pelessa.

The vegetation in both places has a savanna-like physiognomy though the woody plants are somewhat stunted. Dominant non-woody species is the tussock agrass, Cytnbopogon flezuosus Wats. This grass (max. Height 1.2m) along with other herbaceous and low woody plants provide a dense cover. The woody species are scattered apart.

In Ginigal-Pelessa 15 plant species belonging to 12 families were identified in the sampling quadrats.Based onlife form their distribution is as follow:herbs /grasses 03,creepers 02,low shrub spp. 02 shrub spp.05 and tree spp. 03.Among all woody specie Morinda tinctoria Roxb, is the most abundant.Spacial attributes are; mean distance 1.8m max. distance 25.6 m and min.distance 3.2m. Density of trees is 18 /1000m;, Max. tree height is 4m.

In Indikola-pelessa, a place of archaeological importance, 23 species belonging to 16 families were found. Their life form distribution is as follows: herbs/grasses 01, creepers 04, low shrub spp. 03, shrub spp. 03 and tree spp. 12. The dominance of Morinda tinctoria is not seen in this locality. Spartial atrtributes are; mean distance 4.465m. max distance 9.30m and min. Distance 1.9m. Dinsity of trees is 39/1000m2. Max. tree height is 3.5m whereas most of the tree species are in shrub form.

Absence of succulent xerophytes in both areas is striking. This suggests that microhabitat aridity is not a factor. Yet, the stunted nature of the plants may be due to other edaphic factors (e.g. shallow soil profile, mineralogical conditions). In both places periodic burning as in patanas, is an arresting factor.

In relatively undisturbed sites, near-normal growth of such wood species as Azadirachta indica A Juss. (neem), Teminalia catappa L. (Kottamba), Anatardium occidentale L. (cashew) and leucaena leucocephala Lam, (ipil-ipil) indicates that deep-rooted perennials can do well in these serpentine areas. Therefore, the area seems sustable for conservation forestry and wood-fuel lots.


A S Seneviratne', H G Nandadasa2,W.S.Fernando3, H H V M Sanjeevani2 and R L H R Rajapakse2 '
1Department of Botany, University of Colombo
2 Department of Botany, University of Sri Jayewardenepura
3Department of Chemistry . University of Sri Jayewardenepura

The vegetation of serpentine soils has fascinated plant taxonomists, physiologists and ecologists. ~ Many serpentine plant species are used as indicator plants in geo-botanical exploration of mineral deposits and phyto-remediation of polluted soils. Some of the world's serpentine plants have the remarkable ability to selectively accumulate Ni from the soil.

Serpentine body at Ussangoda is overlaid with an ultrmattc soil, which is characteristically rich in Ni, Cr, Fe and Mg. The plain is called 'Rathupas thalawa' - Red soil plain - due to the deep red color of the soil. It is host to a unique type of vegetation tolerant of toxic edaphic condition. As is characteristic of serpentine floras in other parts of the world the vegetation is sparse and the species diversity is low. The plants are stunted prostate in habit and show stress features. The vegetation contrasts sharply with the adjacent non-serpentine vegetation of thorny scrubland and is comprised of plant associations dominated by Hyabanthus enneaspertnus, Evolvulu.s alsinoides, Fimbristylis falcata, Eutp/torbia indica, Crotolaria latebrosa and Blunrea obliyua. Among the other plants which are confined to specific areas on the plain and are of limited distribution are Phyllanthus simplex, Mollugo nudicattlis, Cassia mimosoides, Chlorophyton taxum, Fimbrisrylis acuminata, Polygala javana, Ischaenutm tintorense and Striga etrphrasiodes.

All the plants listed above are serpentine facultative. Of special significance is the occurrence of two types of Evolvulus alsinoides wither with blue flowers or with whiteflowers. Hybanthus enneaspermus is also found in two types either with pink flowers or with white flowers. The two flower types of Evolvuhus show distinct llavonoid profiles on paper chromatograms. The existence of 'flavonoid races' has been reported from other serpentine soils in the world.

The Ni content of the species analysed ranges from 173-2173 ppm on a dry weight basis and is as follows. Hybanthus enneaspermus 2174 ppm, Striga euphrasioide.s 1400 ppm, Cassia ntimosoides 1140 ppm, Bluntea obliqua 1054 ppm, Evolvulus alsinoides 1023 ppm, and Crotolaria latebrosa 604 ppm. This signifies that the mechanism of Ni tolerance is either detoxification and or extrusion rather than exclusion.

While the normal Ni content in plants is reported to be 2-15 ppm, all the serpentine species which we have analyzed were found to be accumulators (>100ppm.). Six of these were hyperaccumulators (>100ppm.). The significance of the above findings and the urgent necessity to conserve this unique vegetation and its habitat will be discussed.

Friday, September 15, 2006

Abstracts of the papers presented at Forestry and Environmenet symposium 2000

Read all the abstracts of the papers presented at Forestry and Environmenet symposium, organized by Department of Forestry and Environment Science, University of Sri Jayewardenapura, Sri Lanka.

This was the 6th symposium in this series of annual symposia. Theme of the symposium was: Development in Environmental Sciences in Sri Lanka. This was held on 15 - 16 December 2000 at Le Kandyan Hotel, Kandy, Sri Lanka.