Conference Presentations by W.V. Tharindu Amarasinghe
Proceedings of the International Forestry and Environment Symposium , 2024
Wood anatomy is a rapid method for identifying different timber species. Shorea is a diverse genu... more Wood anatomy is a rapid method for identifying different timber species. Shorea is a diverse genus of trees in the subfamily Dipterocarpaceae and encompasses a group of some 470 tree species that dominate much of the tropical forests of South and Southeast Asia. Many of these are valued commercially for their hardwoods. However, the anatomical identification of Shorea sp. in Sri Lanka has not been fully studied yet. Six Shorea species available in the lowland wet agroecological zone in Ratnapura District, in Sri Lanka, were selected for this study. The study was conducted in the wood Science laboratory of the State Timber Corporation, Sri Lanka. Six Shorea species, including Beraliya dun (S. disticha), Navada dun (S. stupularis), Dun (S. zeylanica), Yakahalu dun (S. trapezifolia), Yakal dun (S. astylosa) and Thiniya dun (S. congestiflora) were used to identify the variation of wood anatomical features to differentiate the species. As a reference, the Publication List of the International Association of Wood Anatomists on anatomical characteristics was used. To determine the microscopic features, six wood sections (Radial, Tangential, and Transverse sections of the wood) representing each species were employed. The anatomical characteristics of the timber were examined using Micrometrics SE Premium 4 software. According to the results, Yakahal Dun species showed the highest number of vessels and Navada represented the lowest number of vessels. The highest value for the vessel diameter showed the Thiniya species and the lowest for the Dun. Beraliya species showed the highest no of rays and the lowest number of rays showed in Yakahalu dun. A Dichotomous key was developed for the exact identification of Shorea species based on the anatomical characteristics.
International Conference on Building Resilience in Tropical Agroecosystems (BRITAE), 2023
Eucalyptus grandis (EG) is one of the major lengthy construction timber in Sri Lanka. Severe weat... more Eucalyptus grandis (EG) is one of the major lengthy construction timber in Sri Lanka. Severe weather and rough terrain restrain the continuous timber supply; some converted logs of EG plantations might be stored in outdoor yards inside the plantations for a few months. Moreover, illegal timber and timber of hazard trees have to be kept long period at the felling sites due to lack of accessibility or high supply cost. The goal of the present study is to better understand how the wood quality of EG logs degrades over time under natural conditions. Logs of a 24-year-old EG plantation in WU 2 agro-ecological region were selected that were stocked in an outdoor yard while samples of fresh logs of nearby trees were collected as the control. The stocked logs were kept for 24 months; thereafter-wood samples were extracted. All samples were collected from heartwood and strength properties; bending strength Modulus of Rupture, Modulus of Elasticity, Compression Parallel to Grain, and wood density of all samples were tested. Splitting and decayed features of the logs were studied. The independent t-test results show that no significant difference in tested properties between control and exposed logs (P<0.05). The sapwood has completely decayed; hence, 30% of the total log volume has been lost. Both ends of the logs have split, mean splitting length is 1.23 m. the conclusions are; 24 months of the explosion is not affecting on wood strength of the heartwood, however, sapwood is unusable. Splitting prevents the production of larger cross-sections of sawn timber.
Open University Research Sessions 2021 (OURS 2021), 2021
Teak is one of the most valuable and popular timber species in the world in terms of both durabil... more Teak is one of the most valuable and popular timber species in the world in terms of both durability and workability. The need of calculating the carbon storage of teak plantations is vital because it is a major forest plantation species of Sri Lanka, while a significant amount of stock is removed annually as clear-felling. Most teak plantations in Sri Lanka are distributed in the dry zone, even though teak in the intermediate zone also plays a major role in the Sri Lankan timber market. Above Ground Carbon (AGC) stocks of teak between climate zones are important for future forest reference level estimations. Agro-ecological regions are local climatic areas which depict a uniform agro-climate, soils, and terrain conditions. Therefore, this study aimed to estimate the difference in carbon stock in teak plantations based on their respective agro-ecological region. Data collection was performed mainly in two plantations situated in Intermediate Zone Low country1 (IL1) and Intermediate Zone Low country3 (IL3) agro-ecological regions and the age of the plantations was 60 years. Sampling points were selected randomly and each sampling points have 10 m x 10 m in size. Field data on Diameter at Breast Height (DBH) and total tree height were collected, and stem volume was calculated according to allometric equations suggested by Forest Inventory Manual of the Forest Department of Sri Lanka. AGC was estimated by the calculated stem volume and several selected parameters (i.e. biomass expansion factor and species-specific wood density) following IPCC guidelines. An independent t-test was used to test the differences of the AGC stock in different agro-ecological regions. AGC in IL1 and IL3 are 36 ± 34.4 and 43.1 ± 35.5 t/ha, respectively. Results further revealed that AGC has no significant difference between the two agro-ecological regions studied (P >0.05). It can be recommended to increase the number of samples and replicates to be taken for further study. In addition, a comparison can be made with dry zone plantations for comparable results.
Open University Research Sessions (OURS 2021), 2021
Defective teak log sales under saw grade are less profitable and conversions of saw grade logs (S... more Defective teak log sales under saw grade are less profitable and conversions of saw grade logs (S) into prime grade logs (PR) by removing defects are highly profitable. But that conversion leads to the loss of some amount of timber yield which might result in an economical loss. The possibility of removing defects to increase grade quality and fulfill the market requirements is still unclear. Therefore, this study aimed to approach a bucking technique to improve the grade quality of teak. Data collection was done at Wiharakanda and Athugalpura plantations in the Kurunegala district. Length of the log and mid circumference (under bark) were recorded by using distance tape with the visually observable defects namely buttresses, knots, bends, hollows, bends and splits. Log volume calculation using Huber's formula and sales prices; normal price (A), sales price within the production region (P1), and sales price outside the production region (P2), were calculated based on the guidelines of State Timber Corporation. The statistical significance of prices between S grade and PR grade logs was determined. A systematic survey was conducted using thirty teak purchasing shops including vendors and sawmills to investigate the market requirement of logs. The mean lengths of saw grade logs from Wiharakanda and Athugalpura were 6.45±0.38 m and 6.37±1.14 m, respectively. According to the survey, 43% of log vendors prefer teak which is classified under the super-luxury class. All teak log vendors were buying teak at the free sale price, without auctioning and 75% of respondents preferred teak from Dry zone viz. Kurunegala, Ampara, Puttalam districts. The most commonly observable deformities at the logging sites were knots, piths, holes and buttresses. Meanwhile, 71% of vendors preferred to buy logs with 1.5-0.7 m mid girth and 6 m or above length. It can be concluded that there was a significant difference in the sales price (P1 and P2) between saw grade logs and converted prime grade logs via the new bucking method at P <0.05 level and finally saw grade logs with defects can be sold as prime grade logs by removing deformities. Since results are highly site-specific, this study should be conducted for different sites of different agroecological regions to develop the more universal bucking approach.
International Conference on Environmental Good Givernance, 2021
Timber is a renewable natural construction material, which can effectively engage in climate chan... more Timber is a renewable natural construction material, which can effectively engage in climate change mitigation strategies, due to the last-long stored carbon. Trees sequester carbon during their life, pulling CO2 from the atmosphere and storing it in their mass. Storing CO2 in wood could be considered as an effective means of mitigating climate change, though; timber processing generates enormous amounts of timber residues, especially in the sawmilling industry, which can rerelease stored carbon. Consequently, it is experiencing, current sawn timber production is facing significant conversion loss and a constraint of crew management in sawmills, those are huge obstacles to effective sawmilling to decrease the production of saw waste. Thus, the objective of this study is to find out facts that involve saw waste management.
Proceedings of the 25th International Forestry and Environment Symposium 2020 of the Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka, 2020
Wooden sleepers have become the major source for railway ties in Sri Lanka over a century, which ... more Wooden sleepers have become the major source for railway ties in Sri Lanka over a century, which are produced by hardwood species, mainly from forest plantations. However, because of lack of appropriate wood sources, their material quality is declining over a decade, thus the criticism has also arisen against their durability. Moreover, concrete sleepers are becoming popular due to their higher durability and mass production quantity, which is a threat to the market of wooden sleepers. Nevertheless, concrete sleepers show comparatively higher negative environmental impact such as greater carbon emission in their life cycle. Thus, improvement of wooden sleepers is essential to regain their popularity for local utility in terms of durability and as a lesser carbon emitter. Sleepers of Eucalyptus grandis (Grandis) and Dipterocarpus zeylanicus (Hora) were tested; 35 incised and 35 un-incised sleepers from each species were used for the study. The moisture of the sleepers was reduced below 28% and incisions were applied parallel to grain (or length of the sleepers) by a locally developed incising machine. The depth and length of the incisions and distance between two parallel incision lines are 13 mm, 20 mm and 25 mm respectively. All sleepers of each species were treated by Coal-tar Creosote wood preservative in full cell process according to the BS 144:1997 Standard. Change of the weight of the sleepers was used to estimate the retention capacity of the preservative. The results show that the retention capacity of sleepers of E. grandis has increased significantly (p≤0.05) by 71% (23.5 kgm-3) after incising process. The increment of retention capacity of sleepers of D. zeylanicus after incising is only 4%, which is not statistically significant. Moreover, un-incised sleepers of D. zeylanicus (121.82±35.21 kgm-3) is significantly higher (p≤0.05) than un-incised sleepers of E. grandis (33.29±12.83 kgm-3). The results concluded that the incising process can be used to increase the retention of E. grandis sleepers. However, incising on sleepers of D. zeylanicus is not effective. The retention capacity of sleepers of D. zeylanicus is higher than sleepers of E. grandis with or without incising.
11th International Conference on Sustainable Built Environment (ICSBE) 2020, 2020
Timber species, Beraliya dun (Shorea disticha), Navada dun (Shorea stupularis), Dun (Shorea zeyla... more Timber species, Beraliya dun (Shorea disticha), Navada dun (Shorea stupularis), Dun (Shorea zeylanica), Yakahalu dun (Shorea trapezifolia), Yakal dun (Shorea astylosa) and Thiniya dun (Shorea congestiflora) are lesser-known timber species belongs to Dipterocarpaceae family in Sri Lanka. Therefore it is important to identify these species and classify according to their timber properties to popularize among people engaged in the timber industry and forest management. In this study wood density, modulus of rupture (MOR), modulus of elasticity (MOE), compression parallel to grain (CNP) and compression perpendicular to the grain (CPG) of six Shorea timber species grown in Rathnapura district in Sri Lanka were investigated. The tests for mechanical properties were performed through the Universal Testing Machine (UTM 100 PC). Determination of the wood anatomical features especially vessels, rays and parenchyma with related to wood physical properties and density also investigated. To study the anatomical features, slides were prepared with small wood section and observed through the microscope using SE premium software and vessel diameter and ray measurements were measured. Six Shorea spp. were identified by using a prepared dichotomous key. The wood density was grouped into four classes as very high, high, medium and low respectively. Out of the six Shorea species, Shorea disticha shows the highest values for MOR and MOE tests and the Shorea trapezifolia was reported as the second highest values for MOR and MOE. Shorea trapezifolia has reported the highest values for CNP, CPG and Tensile strength values. According to the density values, the highest value shown by the Shorea trapezifolia and lowest was from Shorea zeylanica.
24th International Forestry and Environment Symposium, University of Sri Jayawardanapura, Sri Lanka, 2019
Swietenia macrophylla is a well aware timber species in the local market; conversely, knowledge o... more Swietenia macrophylla is a well aware timber species in the local market; conversely, knowledge of locally grown K. senegalensis is limited.
This study compared mechanical and physical characteristics of 25-30 years aged wood of both species to assist in future applications.
K. senegalensis recorded higher mean values for all tested physical properties (wood density) and mechanical properties (Module of Rupture, Module of Elasticity, compression parallel to grain and compression perpendicular to the grain).
However, the wood of more matured trees of both species should be tested and working property comparison of both species is also required in future studies.
Changing the main species and extending the rotation length is an important improved forest manag... more Changing the main species and extending the rotation length is an important improved forest management practices to enhance carbon sequestration in commercial forests, which ensure the financial gain from the carbon market. Eucalypt plantations in higher elevations of Sri Lanka play a vital role for timber production that still have not been included into any carbon market activities. Eucalyptus grandis (EG) is the dominant species due to its fast growth. However, Eucalyptus microcorys (EM) has shown higher wood properties (wood density) over EG. This study aimed to compare carbon sequestration potential of these two species at present rotation length (25 years) and extending the rotation length (ERL). As a chronosequence approach, three monoculture EG plantations (Age 20, 24, 30 years) and three monoculture EM plantations (Age 17, 19, 30 years) were selected. Moreover, 36 sample plots were randomly established and DBH and total tree height of sample trees were measured. Above Ground Carbon (AGC) was calculated by previously developed allometric equations and species-specific wood density. Logarithmic relationships were developed between AGC and age to estimate the growth of AGC with ERL. AGC of EG at age 25 years was considered as Baseline (BL) stock for comparison. BL stock was 144.94 tonnes of carbon per hectare (tC/ha) and EM recorded 21.5% higher AGC stock (176.15 tC/ha) than BL at the present rotation length. ERL by 5 years showed 27.3% (39.57 tC/ha) and 41.2% (59.73 tC/ha) growth of AGC of EG and EM respectively. Furthermore, EG and EM increase AGC by 50.4% (73.03 tC/ha) and 57.8% (83.85 tC/ha) respectively with 10 years ERL. The conclusions are, EM produces higher AGC stock than EG within present rotation length and ERL. However, the difference of AGC between the species is declining with ERL, the reason might be the higher growth rate of EG.
The increase in frequency of drug resistance has discouraged the development of new synthetic ant... more The increase in frequency of drug resistance has discouraged the development of new synthetic antimicrobial drugs. Natural compounds are a source of various therapeutic agents. Fresh tea leaves are rich in polyphenols and well conducted systematic studies could demonstrate clear antimicrobial effect of tea. Sri Lanka plays a vital role in the global orthodox black tea market as a producer and an exporter. Tea cultivated areas are distinguished into three elevations as high grown, medium grown and low grown. This systematic study focused to evaluate the variation of antibacterial properties of Sri Lankan tea grades from different growing regions. Methanol extracts of 109 samples of selected tea grades of low grown and mid grown; Flowery Broken Orange Pekoe Fannings (FBOPF), Flowery Broken Orange Pekoe (FBOP), Orange Pekoe (OP), Orange Pekoe A (OPA) and selected tea grades of high grown; Broken Orange Peko (BOP), Broken Orange Peko Fannings (BOPF) and Dust No. 1 were tested against different bacteria; Staphylococcus aureus, Bacillus cereus, Escherichia co li, Salmonella typhi, Vibrio parahaemolyticus, Vibrio cholerae by means of zone of inhibition, using agar well diffusion assay. The antibacterial activity of tea grades were compared with three standard antibiotics namely Tetracycline, Ampicillin and Penicillin. Antibacterial properties did not vary based on grades for low grown (p = 0.08 at 0.05 significant level) and mid grown (p = 0.08 at 0.05 significant level), but varied based on factory and some bacterial species (S. aureus, B. cereus and V. cholerae). The tea of high grown area recorded significant variation based on grade, factory and species (S. aureus, B. cereus, V. cholera and S. typhi). BOP showed the highest antibacterial properties (9.22 mm). The most susceptible species for tested tea from all three elevations was S. aureus whereas any of the tested tea did not show a significant effect on E. coli and V. parahaemolyticus. Although tea grades of low grown and mid grown did not record clear inhibition on S. typhi, significant inhibition could be observed for high grown tea grades on S. typhi. When compared with three standard antibiotics used all tea grades showed higher antibacterial properties than Ampicillin and Penicillin. Tetracycline recorded higher inhibition on the bacterial species than all tea grades. Further studies are necessary to explore the variations of antibacterial properties on grades, species and factories. Authors wish to acknowledge National Agricultural Research Plan (NARP) of the National Agricultural Research System of Sri Lanka 2011-2013 for providing grants to conduct the research project.
Book Reviews by W.V. Tharindu Amarasinghe
This is a review of new Additions to the National Repository of Science & Technology of Sri Lanka... more This is a review of new Additions to the National Repository of Science & Technology of Sri Lanka in 2012/2013. Above title was mentioned under sub category of Food Science & Technology.
Books by W.V. Tharindu Amarasinghe
Neela Haritha - The Climate Change Magazine of Sri Lanka (Vol. 3), 2020
• This study was conducted to estimate carbon retention potentials in harvested timber logs from ... more • This study was conducted to estimate carbon retention potentials in harvested timber logs from state-owned Teak, Eucalyptus and Pinus Plantations. • Carbon retention potential of logs was estimated based on collected field data and compared with carbon gained by stand trees, which was determined by yield tables. • According to the study, the average carbon retention of all three species is 157.18 tonnes per hectare and the average amount of sequestrated atmospheric CO 2 is 576.86 tonnes per hectare. This study emphasizes that Pinus logs have retained the highest carbon amount (81.68 tonnes per hectare) while Teak reported the lowest (14.34 tonnes per hectare). • According to the results, Eucalyptus shows the highest annual carbon retention per tree (12 kg tree-1 year-1) while Teak shows the least 1.52 kg tree-1 year-1. • Therefore, Eucalyptus contributes to sequester the highest amount of CO 2 (44.04 kg tree-1 year-1) over the other two species.
Papers by W.V. Tharindu Amarasinghe
Lecture Notes in Civil Engineering
Timber species, Beraliya dun (Shorea disticha), Navada dun (Shorea stupularis), Dun (Shorea zeyla... more Timber species, Beraliya dun (Shorea disticha), Navada dun (Shorea stupularis), Dun (Shorea zeylanica), Yakahalu dun (Shorea trapezifolia), Yakal dun (Shorea astylosa) and Thiniya dun (Shorea congestiflora) are lesser-known timber species belongs to Dipterocarpaceae family in Sri Lanka. Therefore it is important to identify these species and classify according to their timber properties to popularize among people engaged in the timber industry and forest management. In this study wood density, modulus of rupture (MOR), modulus of elasticity (MOE), compression parallel to grain (CNP) and compression perpendicular to the grain (CPG) of six Shorea timber species grown in Rathnapura district in Sri Lanka were investigated. The tests for mechanical properties were performed through the Universal Testing Machine (UTM 100 PC). Determination of the wood anatomical features especially vessels, rays and parenchyma with related to wood physical properties and density also investigated. To study the anatomical features, slides were prepared with small wood section and observed through the microscope using SE premium software and vessel diameter and ray measurements were measured. Six Shorea spp. were identified by using a prepared dichotomous key. The wood density was grouped into four classes as very high, high, medium and low respectively. Out of the six Shorea species, Shorea disticha shows the highest values for MOR and MOE tests and the Shorea trapezifolia was reported as the second highest values for MOR and MOE. Shorea trapezifolia has reported the highest values for CNP, CPG and Tensile strength values. According to the density values, the highest value shown by the Shorea trapezifolia and lowest was from Shorea zeylanica.
JOURNAL OF FOREST RESEARCH, 2021
Eucalyptus plantations at higher elevations in Sri Lanka are being confronted by a conflict betwe... more Eucalyptus plantations at higher elevations in Sri Lanka are being confronted by a conflict between
their industrial need maintenance and ecological need conservation. Increasing carbon sequestration
can offer income through carbon markets to minimize profit reductions. Changing the main species
and extending the rotation length (ERL) can increase carbon sequestration; thus, this study aimed to
compare the carbon sequestration of Eucalyptus grandis (EG) and Eucalyptus microcorys (EM) and their
economic benefits. As a chronosequence approach, EG and EM monocultures were selected for data
collection and the above-ground carbon (AGC) was calculated. The AGC of EG at 25 years of age was
considered as the baseline (BL) and a linear model with log-transformed explanation variable was
used to predict AGC growth with ERL. The economic viability of increased AGC was determined based
on the net present value (NPV) and compared with the replanting cost. The BL stock was 175.91 t
ha−1, while there is no significant effect of changing the main species to increase carbon sequestration. ERL by 20%, 40% and 60% can increase carbon sequestration by 13.7%, 25.2% and 35.2%,
respectively. The NPVs of carbon offsets of ERL indicate that all studied ERLs are profitable; however,
NPV is decreasing with the ERL, ERL by 20% recorded the highest NPV.
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Conference Presentations by W.V. Tharindu Amarasinghe
This study compared mechanical and physical characteristics of 25-30 years aged wood of both species to assist in future applications.
K. senegalensis recorded higher mean values for all tested physical properties (wood density) and mechanical properties (Module of Rupture, Module of Elasticity, compression parallel to grain and compression perpendicular to the grain).
However, the wood of more matured trees of both species should be tested and working property comparison of both species is also required in future studies.
Book Reviews by W.V. Tharindu Amarasinghe
Books by W.V. Tharindu Amarasinghe
Papers by W.V. Tharindu Amarasinghe
their industrial need maintenance and ecological need conservation. Increasing carbon sequestration
can offer income through carbon markets to minimize profit reductions. Changing the main species
and extending the rotation length (ERL) can increase carbon sequestration; thus, this study aimed to
compare the carbon sequestration of Eucalyptus grandis (EG) and Eucalyptus microcorys (EM) and their
economic benefits. As a chronosequence approach, EG and EM monocultures were selected for data
collection and the above-ground carbon (AGC) was calculated. The AGC of EG at 25 years of age was
considered as the baseline (BL) and a linear model with log-transformed explanation variable was
used to predict AGC growth with ERL. The economic viability of increased AGC was determined based
on the net present value (NPV) and compared with the replanting cost. The BL stock was 175.91 t
ha−1, while there is no significant effect of changing the main species to increase carbon sequestration. ERL by 20%, 40% and 60% can increase carbon sequestration by 13.7%, 25.2% and 35.2%,
respectively. The NPVs of carbon offsets of ERL indicate that all studied ERLs are profitable; however,
NPV is decreasing with the ERL, ERL by 20% recorded the highest NPV.
This study compared mechanical and physical characteristics of 25-30 years aged wood of both species to assist in future applications.
K. senegalensis recorded higher mean values for all tested physical properties (wood density) and mechanical properties (Module of Rupture, Module of Elasticity, compression parallel to grain and compression perpendicular to the grain).
However, the wood of more matured trees of both species should be tested and working property comparison of both species is also required in future studies.
their industrial need maintenance and ecological need conservation. Increasing carbon sequestration
can offer income through carbon markets to minimize profit reductions. Changing the main species
and extending the rotation length (ERL) can increase carbon sequestration; thus, this study aimed to
compare the carbon sequestration of Eucalyptus grandis (EG) and Eucalyptus microcorys (EM) and their
economic benefits. As a chronosequence approach, EG and EM monocultures were selected for data
collection and the above-ground carbon (AGC) was calculated. The AGC of EG at 25 years of age was
considered as the baseline (BL) and a linear model with log-transformed explanation variable was
used to predict AGC growth with ERL. The economic viability of increased AGC was determined based
on the net present value (NPV) and compared with the replanting cost. The BL stock was 175.91 t
ha−1, while there is no significant effect of changing the main species to increase carbon sequestration. ERL by 20%, 40% and 60% can increase carbon sequestration by 13.7%, 25.2% and 35.2%,
respectively. The NPVs of carbon offsets of ERL indicate that all studied ERLs are profitable; however,
NPV is decreasing with the ERL, ERL by 20% recorded the highest NPV.