http://repository.rjt.ac.lk/handle/123456789/1 2026-04-04T20:46:41Z 2026-04-04T20:46:41Z Warnasooriya, W.M.R.S.K Sivananthawer Hitinayake, H.M.G.S.B. Bandara, A.M.K.R. http://repository.rjt.ac.lk/handle/123456789/8302 2026-03-20T05:54:44Z 2016-02-01T00:00:00Z

SITE QUALITY OF KHAYA (Khaya senegalenesis) PLANTATIONS IN SRI LANKA AS INDICATED BY HEIGHT-DIAMETER RELATION AND TOP HEIGHT TITLE Warnasooriya, W.M.R.S.K; Sivananthawer; Hitinayake, H.M.G.S.B.; Bandara, A.M.K.R. is) being a new introduction, recommended for forest plantation establishment in the Dry and Intermediate Zones of Sri Lanka, assessment of site quality at growing localities is vital. Variables, i.e. tree height and tree diameter were measured non-destructively, at identified age classes of Khaya in Anuradhapura and Kurunegala divisions as representatives of Dry and Intermediate Zones, respectively. Khaya in Kurunegala has achieved 39.98 cm of dbh and 18.31 m of height by the age of 18-20, whereas in Anuradhapura they were 22.21 cm and 12.41 m. The dbh and tree height showed a strong degree of correlation in both divisions. Among the height-diameter models regressed, parabolic model (h = ß 0 + ß 1.d + ß 2.d2) and the model, h – 1.3 = ß 1.d + ß 2.d2 showed the best fit with the available data in Anuradhapura and Kurunegala divisions, respectively. As per height-diameter relation, site quality of the beat Polpithigama in Kurunegala is superior to the beats Ullukkulama and Rathmale in Anuradhapura, while the beat Mihintale in Anuradhapura is superior to the beats Ranawarawa and Ambanpola in the Kurunegala division. Khaya has attained average top heights of 14.2 m and 20.8 m at the base age of 18 20 years in Anuradhapura and Kurunegala divisions, respectively. Elevated top heights demonstrated the richness of site quality in Kurunegala division. Top height being the site index, it can be concluded that the beats Rathmale, Elayapattuwa and Punewa in Anuradhapura and the beats Ranawarawa and Ambanpola in Kurunegala division are inferior, while the beat Mihintale in Anuradhapura and the beats Kuliyapitiya, Nikaweratiya, Nakkawatta and Polpitigama in Kurunegala division are superior in site quality. This confirms that Khaya performs well in the Intermediate Zone than in the Dry Zone of Sri Lanka. Further, it identified the inferior sites for the growth of Khaya. These findings can direct the decision making process on future forest plantation establishment in Sri Lanka with possible refining of present recommendations. Key words: Top height, Height-diameter relation, Khaya senegalensis, Site quality

2016-02-01T00:00:00Z Warnasooriya, W.M.R.S.K Sivanantharwerl, T http://repository.rjt.ac.lk/handle/123456789/8301 2026-03-20T05:40:02Z 2015-01-01T00:00:00Z

KHAYA (Khaya senegalensis): IS IT A POTENTIAL PLANTATION FOREST SPECIES FOR CLIMATE CHANGE MITIGATION IN SRI LANKA? Warnasooriya, W.M.R.S.K; Sivanantharwerl, T ABSTRACT Carbon sequestration by tree is imperative in tumbling atmospheric carbon dioxide level. Hence, forest plantations are considered highly efficient systems for carbon sequestration, which plays a vital role in climate change mitigation. While, carbon sequestrations of forest plantations were little focused in Sri Lankan context, present study aims to validate its potential, using Khaya plantations in Anuradhapura and Kurunegala divisions of Sri Lanka. Variables, i.e. tree height and tree diameter were measured non-destructively at identified age classes to estimate biomass using allometric equations. DL1b being the sole agro ecological region in Anuradhapura, resulted less variation in biomass distribution through age classes, whereas it was irregular in Kurunegala, visualizing the climate variation of the different agro ecological regions (DL1b, IL3, IL1a, IM3b) within the division. Greater biomass of Khaya recorded in Kurunegala was attributed to moisture rich growing conditions, whereas lower biomass in Anuradhapura resulted with less annual rainfall and prolonged drought, indicating the strong association of biomass with environmental stress. Greater root:shoot ratio (R/S) of Khaya was observed in Anuradhapuara, while R/S had decreased through age classes in both divisions. The average above ground carbon sequestration of Khaya i.e. 88.98 and 127.92 tonnes per ha in Anuradhapura and Kurunegala divisions were well ahead of the IPCC’s benchmark of plantation forests in ‘Tropical Dry’ climate i.e. 30 tonnes per ha, indicating its potential of climate change mitigation, besides the timber use. The total amount of carbon sequestered by existing Khaya plantations amounted to 21,785.25 and 27,969.10 tonnes in Anuradhapura (741.92 ha) and Kurunegala (475.20 ha) divisions, respectively. Despite the greater extent, Khaya in Anuradhapura assimilated less carbon due to stressful conditions imposed by climate and being in younger age classes. While, carbon estimates enable economic valuation of forest plantations in the context of carbon crediting, the regional baseline carbon estimates of Khaya generated by present study can be effectively utilized for carbon budgeting programmes, until further validated with comprehensive survey of individual trees and by developing allometric relationships specific for Khaya senegalansis. Key words: Khaya senegalensis, Carbon sequestration, Climate change mitigation, Biomass, Age classes

2015-01-01T00:00:00Z Warnasooriya, W.M.R.S.K Sivanantharwerl, . T. http://repository.rjt.ac.lk/handle/123456789/8300 2026-03-20T05:33:52Z 2015-09-12T00:00:00Z

IS IT A POTENTIAL PLANTATION FOREST SPECIES FOR CLIMATE CHANGE MITIGATION IN SRI LANKA? Warnasooriya, W.M.R.S.K; Sivanantharwerl, . T. stration by tree is imperative in tumbling atmospheric carbon dioxide level. Hence, forest plantations are considered highly efficient systems for carbon sequestration, which plays a vital role in climate change mitigation. While, carbon sequestrations of forest plantations were little focused in Sri Lankan context, present study aims to validate its potential, using Khaya plantations in Anuradhapura and Kurunegala divisions of Sri Lanka. Variables, i.e. tree height and tree diameter were measured non-destructively at identified age classes to estimate biomass using allometric equations. DL1b being the sole agro ecological region in Anuradhapura, resulted less variation in biomass distribution through age classes, whereas it was irregular in Kurunegala, visualizing the climate variation of the different agro ecological regions (DL1b, IL3, IL1a, IM3b) within the division. Greater biomass of Khaya recorded in Kurunegala was attributed to moisture rich growing conditions, whereas lower biomass in Anuradhapura resulted with less annual rainfall and prolonged drought, indicating the strong association of biomass with environmental stress. Greater root:shoot ratio (R/S) of Khaya was observed in Anuradhapuara, while R/S had decreased through age classes in both divisions. The average above ground carbon sequestration of Khaya i.e. 88.98 and 127.92 tonnes per ha in Anuradhapura and Kurunegala divisions were well ahead of the IPCC’s benchmark of plantation forests in ‘Tropical Dry’ climate i.e. 30 tonnes per ha, indicating its potential of climate change mitigation, besides the timber use. The total amount of carbon sequestered by existing Khaya plantations amounted to 21,785.25 and 27,969.10 tonnes in Anuradhapura (741.92 ha) and Kurunegala (475.20 ha) divisions, respectively. Despite the greater extent, Khaya in Anuradhapura assimilated less carbon due to stressful conditions imposed by climate and being in younger age classes. While, carbon estimates enable economic valuation of forest plantations in the context of carbon crediting, the regional baseline carbon estimates of Khaya generated by present study can be effectively utilized for carbon budgeting programmes, until further validated with comprehensive survey of individual trees and by developing allometric relationships specific for Khaya senegalansis. Key words: Khaya senegalensis; Carbon sequestration; Climate change mitigation; Biomass; Age classes

2015-09-12T00:00:00Z Thilakarathne, MGOS Senanayake, PSWL Bandara, BGRR Liyanage, WLAM Dissanayake, HDMAC Warnasooriya, WMRSK Samarasinghe, CRK Weerasinghe, PR http://repository.rjt.ac.lk/handle/123456789/8299 2026-03-20T05:24:50Z 2023-12-01T00:00:00Z

A COMPARATIVE ASSESSMENT OF FRUIT COMPONENTS OF RECOMMENDED COCONUT (Cocos nucifera L.) CULTIVARS IN SRI LANKA Thilakarathne, MGOS; Senanayake, PSWL; Bandara, BGRR; Liyanage, WLAM; Dissanayake, HDMAC; Warnasooriya, WMRSK; Samarasinghe, CRK; Weerasinghe, PR

2023-12-01T00:00:00Z