Participatory Forestry in Sri Lanka: Success or Failure?

Presentation Abstract

Dinuka Senevirathne

Department of Forestry and Environmental Science

University of Sri Jayewardenepura, Sri Lanka

Sri Lanka was once a heavily forested island, but over the present century its forest cover has declined markedly to about 29%. Historically, much of the loss may be attributed to the creation during colonial times of plantations of tea, rubber, coconut and other crops. In the last decade the greatest single cause of deforestation has been the accelerated Mahaweli Development Program, a major irrigation scheme fed by a series of dams across Sri Lanka's largest river. Although not always publicly acknowledged, this resulted in the clearance of substantial areas of natural forests. However, in the 1980s there was a widespread recognition of a need for reforestation and forest conservation measures in both government and donor circles. Although there had been attempts to launch social forestry practices in Sri Lanka, forest management on a truly participatory basis was not taken place, because local people have not actively involved in tree or forest management in partnership with the Forest Department. The program have been run in many ways namely Taunga, reforestation, community forestry, participatory forestry, natural resource development. All those programs were implemented based on different aspects. Mainly the success of a program depends on the social factors, dependency on forest and awareness of the outcome. As per Sri Lanka socially now there are no much of tribes but people live as individuals and question the procedures in their own manner. Therefore it is actually hard to continue such community programs. On the other hand, the dependency on the forests or forest products declined at major level in Sri Lanka. Therefore it was hard to convince the people to work in such programs. However, different incentives were given to encourage the participation. Recent studies conducted on social forestry programs identified the need of institutional support to conduct such programs in successful manner.

Tree Selection for the Enrichment of Lower Areas of Kalu Ganga River Basin

Presentation Abstract

Chathuri Liyanage

Department of Forestry and Environmental Science

University of Sri Jayewardenepura, Sri Lanka

Kalu Ganga which is also known as the “Black River” is the second largest river in Sri Lanka. It originates from the central hills of mountain Sri Pada and falls to the sea in Kalutara after travelling for 129 km. Kalu Ganga river basin in Sri Lanka has an extent of 2,766 km². Its river basin is situated entirely in the wet zone of Sri Lanka. The average annual rainfall in this area is 4,000 mm and it varies from 2,800 mm which is for the lower reaches to about 5,300 mm for the upper reaches of the basin. The average slope of the basin is steep in the upper catchment from about 30-70 degrees and it becomes gentle to very gentle from the middle catchment(0-30 degrees) to the lower catchment(0-10 degrees). As a result, runoff abruptly changes from very fast in the upper catchment to very slow in the lower catchment corresponding to the slope angle. Due to the change of slope angle, bottleneck at Ellagawa and due to illegal sand mining activities, the lower basin area suffers from floods. It also causes for the erosion at river banks. Therefore the river basin should be enriched with suitable native trees like Hora (Dipterocarpus zeylanicus), Walla-Patta (Gyrinops walla), Gon-kanduru (Cerbera odollam), Asoka (Saraca asoca) and Goda-Midella (Barringtonia racemosa (L.) Spreng) which are the native trees growing in wet-lowland forests. Dry zone trees such as Kumbuk (Terminalia arjuna) and Mee (Madhuca longifolia) can also be used as they grow successfully near waterways. Tree selection for the enrichment should be done considering many factors such as tree characteristics (height, growth rate etc.), use (medicinal and aesthetic value etc.). Developing a system for the regular monitoring of the river basin and to take remedial actions to correct negative trends are recommended to ensure the conservation of riverine areas. Further, illegal sand mining activities should be controlled by imposing laws and higher penalties.

Tree Selection for the Enrichment of Mahaweli River Basin in the Dry Zone, Sri Lanka

Presentation Abstract

Hirusha Randimal

Department of Forestry and Environmental Science

University of Sri Jayewardenepura, Sri Lanka

Mahaweli is the longest river in Sri Lanka the Mahaweli Development Project has been established by taking this river as the central component. Due to the topography, it carries a large sediment load and the lateral part of the River consists with large alluvium deposits. Mahaweli river basin in the dry zone divided Mahaweli plain, Bintanne plain, Nuwarakalawiya plain and Flood plain consist with Villus ecosystems The major land use around the Mahaweli river in the Dry Zone is paddy cultivation. The water management schemes established under the above project have changed the natural flow regimes, resulting in sometimes higher flood flows, lower dry season flows and degradation of riparian and wetland habitats in the lower catchment. River banks erode along with onset northeast monsoon and inter-monsoonal rains due to lack of riverine vegetation. In order to enrich the river banks of those areas, tree species should be selected which suit for riverine ecosystems as well as intermediate and dry agro-ecological zones. Terminalia arjuna (Kumbuk), Madhuca longifolia (Mee), Barringtonia acutangiila (Ela midella) and Diospyrous malabaria (Thimbiri) are some of the species which can use for enrichment. Further, eradication and management of invasive species such as Mimosa pigra  and also proper enrichment model should be implemented and continuous monitoring should done for such kind of degrading ecosystem. Through a proper management of the riverine vegetation, sustainable extraction of timber and other forest products from such ecosystems should be the longer-term goal.

Variation of Volatile Oil Contents and Constituents in Lesser Known Plant Species for Formulating Mosquito Repellents

Abstract

Presented at the 22nd International Forestry and Environment Symposium

11 November 2017

Madhubhashani Weerasinghe, Upul Subasinghe, Dhanushka Hettiarachchi

Volatile oils also known as essential oils are found in aromatic plants and contain volatile compounds that contribute to particular fragrances and flavours. Main uses of these volatile oils range from aroma therapy, food additives, cosmetics, natural medicines to insect repellents. Although there are common plants that produce volatile oils capable as mosquito repellents, certain plants are not known for this ability or under-utilised. Therefore, this research aimed at identifying lesser known volatile oil producing species and to formulate the plant products into safe and low cost insect repellents. An expert survey was first conducted by interviewing 7 subject experts and 13 local ayurvedic practitioners to identify the existing and potential volatile oil producing plant species which can be used as mosquito repellents. This survey identified 60 species and out of those 16 species (Ocimum tenuiflorum, Azadirachta indica, Acorus calamus, Atalantia ceylanica, Ocimum sanctum, Plectranthus amboinicus, Plectranthus zatarhendi, Vetiveria zizanioides, Acronychia pendunculata, Osmium gratissium, Aegle marmelos, Limonia acidissima, Murraya koenigii, Ricinus communis, Cinnamomum verum and Tagetes erecta) was selected after a weighted ranking system for further study. Hydro-distillation for 5 hours was used with 100 g of leaves for oil extraction for each species with three replicates. Particle size was kept at 1.5 cm for this purpose with 1:12 water ratio. Oil constituents were identified using GC-MS analysis. According to the results C. verum yielded the highest mean oil content (0.0113±0.0024 ml/g) followed by A. marmelos (0.0095±0.0018 ml/g). 0.0018 ml/g). 0.0018 ml/g). 0.0018 ml/g). 0.0018 ml/g). A. ceylanica bears the highest number of constituents followed by M. koenigii and L. acidissima. However, the highest number of constituents which act as mosquito repellents showed by L. acidissima and C. verum as the present study. Those constituents are α-Pinene, 3-Carene, Terpinolene, Caryophyllene oxide in C. verum and α-Pinene, Limonene, Terpinolene and Caryophyllene oxide in L. acidissima.

Limonia acidissima (Wood apple) tree

Determination of Rotation Period and Scheduling Harvesting and Replanting

Abstract of a presentation conducted by

Gimhani Danushika

Department of Forestry and Environmental Science

University of Sri Jayewardenepura, Sri Lanka

The objectives in forest management are often achieved by controlling the characteristics of a forest stand or set of forest stands in to influence the growth and yield of those stands. Further according to the objective of the land owner, it will change optimal rotation period of the plantations rotation. Most government owned plantations are following biological rotation to determine harvesting age of the plantation while commercial plantations are managed with economic rotation to get maximum economic benefit.

Harvest scheduling is a traditional exercise carried out by forest land managers on public and private lands. Public land management has characteristically balanced timber and non-commodity forest production while private land is going for optimal timber production. Therefore, industrial plantation establishment has been dominated by profit maximization and cost reduction by various strategies like economies of scale. Forest harvest practices in Sri Lanka are conducted by two ways called thinning and final harvesting. Final harvesting can be done in different ways such as clear cutting where all trees are felled, while selective cutting, shelterwood cutting and seed tree cutting are also possible. Thinning generate additional intermediate income from plantation while improving site quality for plant grooving by reducing competition.

Replanting of a harvested site is an important managerial activity which depends on social, cultural, economic and environmental considerations. According to management decision, it can use the same species as before or different species appropriate to the land. When replanting is carrying out, proper silvicultural practices should be maintained to gain the final harvest as expected levels. e:g: nursery establishment and maintaining, establishment of pits for planting, spacing, block wise replanting, weeding, fertilizing, irrigation, thinning and pruning etc. All these action should be conducted in proper way to maintain good replanting practice in harvested land.

Land Evaluation and Species-Site Suitability Determination for Forest Plantation Establishment

Abstract of a presentation conducted by

Sohani Vithanage

Department of Forestry and Environmental Science

University of Sri Jayewardenepura, Sri Lanka

Decisions about the use of land have always been a part of human society. Forestry planning has always taken account of the influence of conditions of land in taking management decisions. The approach and methods of land evaluation were developed in order to provide a systematic framework for assessing the effects of land on potential benefits of each land use. Land evaluation is based upon a comparison between land use and land type. Land use related to forestry can be broadly categorized as production forestry, conservation forestry, recreational forestry and community forestry. These major land uses can be further described in detail according to tree species, silvicultural methods, harvesting practices etc. The focus of land evaluation is to access the requirements and limitation of each of this land use and to compare this with the properties of land.

In the process of land evaluation land use requirements for each identified land utilization type is defined. Simultaneously, land qualities and characteristics of each land unit is described using literature surveys and ground surveys. These data is then coupled with economic and social data to develop a comprehensive comparison of land use with land. The outputs of land evaluation can be presented in terms of land suitability classifications or land suitability maps. At present, this procedure can be carried out with the help of computerized land evaluation systems and geographic information systems. In determining the species site suitability for forest plantation establishment, three aspects have to be considered. They are purpose of plantation, species availability and environmental conditions. For this process, depending on the species and sites, information survey can extend from local level to international level.

Land Evaluation and Species-Site Suitability Determination for Forest Plantation Establishment

Abstract of a presentation conducted by

Sohani Vithanage

Department of Forestry and Environmental Science

University of Sri Jayewardenepura, Sri Lanka

Decisions about the use of land have always been a part of human society. Forestry planning has always taken account of the influence of conditions of land in taking management decisions. The approach and methods of land evaluation were developed in order to provide a systematic framework for assessing the effects of land on potential benefits of each land use. Land evaluation is based upon a comparison between land use and land type. Land use related to forestry can be broadly categorized as production forestry, conservation forestry, recreational forestry and community forestry. These major land uses can be further described in detail according to tree species, silvicultural methods, harvesting practices etc. The focus of land evaluation is to access the requirements and limitation of each of this land use and to compare this with the properties of land.

In the process of land evaluation land use requirements for each identified land utilization type is defined. Simultaneously, land qualities and characteristics of each land unit is described using literature surveys and ground surveys. These data is then coupled with economic and social data to develop a comprehensive comparison of land use with land. The outputs of land evaluation can be presented in terms of land suitability classifications or land suitability maps. At present, this procedure can be carried out with the help of computerized land evaluation systems and geographic information systems. In determining the species site suitability for forest plantation establishment, three aspects have to be considered. They are purpose of plantation, species availability and environmental conditions. For this process, depending on the species and sites, information survey can extend from local level to international level.