Thursday, November 16, 2017

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

Monday, September 19, 2016

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.


Friday, September 16, 2016

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.




Tuesday, September 13, 2016

Site Quality Improvement in Forest Management

Abstract of a presentation conducted by
Kushani Perera
Department of Forestry and Environmental Science
University of Sri Jayewardenepura, Sri Lanka

The productivity of a site for tree growth is usually evaluated on a stand basis. Considered in this way, site quality expresses the average productivity of a designated land area for growing forest trees. A common way of expressing relative site quality is to set up from three to five classes, or ordinal ranks, such as site I, II and III. The characteristics of each class must be defined to enable any area to be classified.

Site is a complex of physical and biological factors of an area that determine what forest or other vegetation it may carry. Sites get degraded due to many reasons, especially due to human induced problems such as land clearance, clear cutting and deforestation, agricultural depletion of soil nutrients through poor farming practices, livestock including overgrazing, dumping of non-degradable trash, plastics etc.

Site quality is a measure of relative productive capacity of a site for a particular species.Different site gives different growth response to different species. Site quality can be influenced by climatic factors, topographic factors, soil edaphic factors and competition. Monitoring site quality is important to match the species with the site, to estimate the quantity (harvest prediction) and the quality of the timber, to monitor overall ecosystem productivity, diversity and resilience and to check the habitat type and quality.

Site quality can be evaluated by both direct (actual crop production) and indirect factors (plant indicators, crop statistics, site factors).The quality of the original site can be improved by using several silvicultural practices like fertilization, improving the quality of soil by using cover crops, mulches and mechanical methods such as plouging, harrowing and deep ripping of the soil to improve aeration and at the same time mixing the organic matter content of the soil.



Non Timber Forest Products Manufacturing and Marketing with Special Reference to Aromatic Oils

Abstract of a presentation conducted by
T Venukasan
Department of Forestry and Environmental Science
University of Sri Jayewardenpura, Sri Lanka


Non-timber forest products (NTFPs) are any product or service other than timber that is produced in forests. They include fruits and nuts, vegetables, fish and game, medicinal plants, resins, essences and a range of barks and fibres such as bamboo, rattans, and a host of other palms and grasses. Here forest products can be classified into two main pats timber and non-timber forest products where scope of this study remains at essential oils mainly focusing on Agarwood and Sandalwood.

Agarwood is aromatic, dark, fragrant resinous substance that is produced by certain plant members of family Thymaleaceae including specially Gyrinops and Aquilaria trees. It has a high demand in globally and considered as the most expensive wood in the world. Agarwood resin formation due to natural reasons is rare and slow. Therefore resin formation is induced at commercial scale using different techniques. Both the quantity and quality of Agarwood resins is dependent on the inducement technique and therefore the use of the right method is vital to increase the product quality and income. Sandalwood oil is extracted from wood and roots of the tree. Sandalwood oil has a characteristic sweet, woody odour which is widely employed in the fragrance industry, but more particularly in the higher-priced perfumes. And also it is used in aromatherapy, cosmetic industry and to prepare soaps due to the antimicrobial activity. Unlike other aromatic wood they retain their fragrance for decades.

Citronella oil production can be highly promoted among local communities though it has been declined as it makes high profits in international market. Citronella oil is a source of important perfumery chemicals which find extensive use in soap, perfumery, cosmetic and flavouring industries. Leaves of Citronella plant are distilled to obtain valuable oil. It is a common mosquito repellent and also used in indigenous medicine as well as in flavouring food and alcoholic drinks in certain countries.

When considering the international market of aromatic oils, the current global value of the Agarwood trade is USD 6-12 billion. The annual supply of all forms of good quality Agarwood is about 6,000 MT which is 40% of the actual demand. Current market leaders in exportation of Sandalwood oil are India and Indonesia, while United States and France are the two largest importers of Indian Sandalwood oil. Although illegal logging is a major problem faced by the local industry, establishment of commercial S. album and Aquilaria plantations have recently become popular among the private sector. When Citronella oil is considered, Indonesia and China are the current suppliers for the global market. With proper technology and government support, Sri Lanka has the opportunity to become a potential exporter of Citronella oil.




Saturday, September 10, 2016

Forest Certification and Challenges Faced by the Forest Owners

Abstract of a presentation conducted by
Kalani Nayanthika
Department of Forestry and Environmental Science
University of Sri Jayewardenepura, Sri Lanka

Forest certification is a process which results in a written certification being issued by an independent third party, attesting to the location and management status of a forest. It is a powerful marketing tool and widely recognized as a useful component to stimulate movement toward sustainable management. Forest certification originated in the early 1990s as a means to protect forests from exploitative harvesting.

By certifying the management of certain forests, wood products made from that timber could be labeled as “certified”. It involves assessing the quality of forest management in relation to a set of predetermined principles and criteria. It provides consumers a credible guarantee that the product comes from environmentally responsible, socially beneficial, and economically viable sustainably managed forests and also ensures that management does not diminish the value of the future forest, nor create hardships for local communities.

Certifying the forest has now become an increasing tread which provides financial, environmental and social benefits.

There are three types of forest certifications called as Forest Management, Group Certification and Chain of Custody. There are also several Forest Certification Programs in the world. The Forest Stewardship (FSC) certification is one of the popular program used in worldwide.

The global FSC standard is comprised of ten principles that cover a range of environmental, social, and economic criteria. Although there are regional variations on how the standards are applied to address the unique needs of forests, peoples, and economies in different parts of the world, the basic tenets remain the same.

From the sustainable practices followed in certification process, several social, economic and environmental benefits can be achieved. There are several opportunities which can be achieved from this certification such as increase image of the product.


There are also several challenges with regard to this certification processes such as difficulties in maintaining chain of custody from forest to the customers, difficult to justify the cost of certification. Most companies are curious or unclear about the benefits and opportunities they can derive through certification, effects from the surrounding areas where there are no sustainable practices and changing standards with time.