Pest Management in Commercial Forestry

Presented by

Madhushi Weerasinghe

Forest Pest can be defined as “any insect, disease or closely related organism which is harmful, injurious, or destructive to forest or timber”. All parts of a tree roots, stems, foliage, shoots and terminal leaders are vulnerable to attack by pests. Pest damage can range from slight damage that has no effect on the value of the harvested product to severe damage that stunts or kills the trees or reduces their market value. Tree pests include insects and mites, diseases, vertebrates, and nematodes.

There are several common pests that can be commonly seen in commercial forestry. In Tectona grandis the most common insects cause severe damage plantations are Leaf Skeletonizer (Eutectona machaeralis) and Defoliator (Hyblaea puera). In Swietenia macrophylla the most common pest is Mahogany Shoot Borer (Hypsipyla grandella). Moreover, there are insect pests in Eucalyptus grandis, such as Eucalyptus gall wasp (Ophelimus maskelli). Also some pathogens such as Leaf Spot Fungi (Cryptosporiopis eucalypti),Cylindrocladium Leaf Spot Blight-Fungi (Cylindrocladium reteaudii), Botryoshharia Canker (Botryosphaeria spp.) and Bacterial Wilt (Ralstonia solanacerum) are common. In Aquilaria malaccensis, Leaf spot Disease caused by Corynespora cassicola is common. Considering Sandalwood (Santalum album L.) there are some nursery diseases such as Damping off and Pre-emergence wilt.Also forest plantations can be damaged by Elephants and small mammals.

Managing tree pests effectively should be based on thorough consideration of ecological and economic factors. The pest, its biology, and the type of damage are some of the factors that determine which control strategies and methods should be used. Pest management decisions represent a compromise between the value of the product, the extent of the pest damage, the relative effectiveness and cost of the control measures, and the impact on the environment.

Here the concept of Integrated Pest Management (IPM) is mainly used. That relies on an understanding of the ecology of the pest, draws on this knowledge non-chemical approaches that will make the environment less suited to the development of the pest population. Integrated Pest Management practice may involve in the control program, the judicious and sensitive use of pesticides where necessary. There are five major steps in IPM. Monitoring is the first step. Monitoring forests and newly established plantations will help detect problems early, while there is still time to take action. Identification of pests and the diagnosis of pest damage is the second step of IPM. Threshold level is point at which the pest or its damage becomes unacceptable. The threshold level may be related to the beauty, health, or economic value of the tree crop and that comes as the third step of IPM. Selection of management strategy is fourth step and under this there are several management strategies such as, do nothing, cultural management, mechanical management, biological management and chemical management. Evaluation is the final step of IPM. It is very important to determine how effective the management and control tactics are. This information will determine whether any follow-up treatment is needed and will improve management strategies for next year.

Insect Management in Commercial Forestry

Presented by

Pabasara Gunawardane

All parts of a tree are vulnerable to attack by pests. Pest damage can range from slight damage that has no effect on the value of the harvested product, to severe damage that stunts or kills the trees or reduces their market value. Tree pests include insects and mites, diseases, weeds, vertebrates, and nematodes. 

Insects belong to the kingdom Animalia and in the phylum Arthropoda. Insects are categorised under the class Insecta. More than one million different species of insects have been identified. Some insects of orders such as Coleoptera, Lepidoptera, Hymenoptera, Hemiptera, Isoptera and Orthoptera are considered as pests in plantation forestry. Tectona grandis, Eucalyptus sp. Swietenia macrophylla, Santalum album and Aquilaria sp. are some of the major plantation species in Sri Lanka and the world

When consider about the insects, at least 174 species of insects have been recorded from the living teak tree. Most of these insects are not economically significant in their attacks. Teak defoliator (Hyblaea puera) causes severe defoliation and, hence, reduce growth rate of the tree. The larva of leaf skeletonizer (Eutectona machaeralis) feeds on the green leaf tissue between the network of veins, leaving the skeleton of veins intact. The most important stem borer in young teak plantations is Zeuzera coffeae. Another stem borer is Xyleutes ceramicus and it is found in older Teak plantations.

More than 920 species of insects are associated in Eucalypts. The most common pest problem of exotic eucalypts is mortality of saplings caused by root-feeding termites. Eucalyptus Gall Wasp has been reported in Sri Lanka in 2010 and it was successfully controlled by natural enemies of the pest insect.

Mahogany shoot borer (Hypsipyla robusta) outbreak is the most severe pest attack found in Mahogany. It is suggested that the relatively low level of attack in Sri Lanka may be due to good overhead shade where the trees have been planted.

Zeuzera coffease (red borer) Indarbela quardinotata (bark-feeding caterpillar) and Aristobia octofasiculata (heartwood borer) are some of the pests causing considerable damage to living Sandalwood trees. In agar plantation no such serious pests and diseases have been observed. A leaf-eating caterpillar (Heortia vitessoides) is considered to be the most destructive pest causing damage by complete defoliation of agar plantations. When compare with the other countries of the region the status of the pest outbreaks in forest plantations are lower in Sri Lanka.

In earlier attempts to control pest the commonly used method was to kill all the pests and with time plantation managers realized that pests need to be controlled only if they cause economic damages. The pest management concept is used to indicate management of the pest population to limit it to a tolerable level. With the advancement of knowledge and the science the concept of integrated pest management (IPM) has been introduced in order to manage the insects and pests in commercial plantations.

Lack of sufficient scientific research, inapplicability of sophisticated pest management methods used in developed countries and having the low attention on the pest management in forest plantation species by the government are major challenges in insect management in Sri Lankan forestry context.

Market Demand and Export of Non-Timber Products

Presented by

Sumudu Marasinghe

All the biological material except industrial round wood, derived sawn timber, wood chips, wood-based panel and pulp are generally considered as non- timber forest products. They may be extracted from natural ecosystems, managed plantations and other resources and be utilised within the household, social, cultural or religious significance. The non- timber forest products are defined as goods of biological origin other than wood, derived from forests, other wooded lands and trees outside the forests. Non- timber products which are exported from Si Lanka are mainly tea, natural rubber, coffee, coconut and coconut based products, cocoa, spices, cashew, ayurvedic & herbal products, bamboo, rattan and cane, essential oils and resins

Sri Lanka has acquired a good demand and reputation for tea and cinnamon in the world market.  Pure Ceylon tea satisfies 19% of global tea demand and Sri Lanka has become the world's third largest tea exporter to the world market. About 96% of the total tea production in our country is exported to about 40 countries. Among those countries United Arab Emirates, Russian Federation and Jordan are the major buyers for Ceylon Tea. When it comes to Cinnamon, Sri Lanka is the world's largest producer and exporter of pure cinnamon and satisfies almost 90% of demand of the world market. Sri Lankan Cinnamon has been established in the international market under the global brand name of Pure Ceylon Cinnamon and it satisfies almost 90% of demand of the world market. USA & Mexico are the main markets and it also exported to countries such as Colombia, Ecuador, Peru, Spain, Guatemala, Chile and Bolivia. Not only raw cinnamon but also value-added Cinnamon products such as oil, powder and tablets are produced and exported. And our country is in the sixth position among the global natural rubber producers. Different types of natural rubber such as ribbed smoked sheet rubber, latex crepe rubber, scrap crepe rubber and centrifuged latex are exported and rubber sector is the third largest export earner of the country. USA, Belgium, Germany, Italy and UK are the main export markets for natural rubber. And Pakistan, India, Malaysia, Japan, Germany are the main export markets for semi-processed Sri Lankan rubber. Another important category is essential oils such as Eucalyptus oil, Cinnamon leaf oil, Cinnamon bark oil and Citronella oil. Pepper, nutmeg and mace, cardamom and clove are some of the main spices which are exported from our country.

According to the Annual report of 2014 produced by Sri Lanka Export Development Board, a considerable success was achieved by all the tea products. The exports were increased in terms of both value and volume by 5.43 % and 2.35% respectively. 48.54% of total tea export earnings were gained by exporting Tea Packets and 49.10 % from exporting bulk tea. But export earnings from all categories of natural rubber were declined during the last year. Overall negative performance of natural rubber exports was -36.32%. Export earnings from coconut oil, fresh coconut nuts, coconut fibre based products and coconut shell products were increased but earnings from export of coconut powder was declined. When considering about the spices, only the exports of cardamom were increased and the exports of other spices such as pepper, cinnamon, clove and nutmeg were declined. 

Several issues in the exporting sector can be identified which inhibit the performances of the exports. Lack of policy objectives on extraction of non – timber products, lack of modern technology on extraction, lack of knowledge and attention to maintain the product quality, lack of experience and knowledge about the opportunities in the international market and competition from the other countries which have more resources and technology than our country are some of those issues. Therefore to overcome those barriers solutions should be designed and adopted such as awareness programmes for farmers to meet the international standards of the products, introducing more efficient technologies to extract the products, research and development programmes to increase the quality and purity of the products and establishing a proper database on the demand and supply of the exporting products.

Harvest Scheduling and Replanting in Comjmercial Forestry

Presented by

Arundathi Koliyabandara

Harvest scheduling is a traditional exercise that has been carried out by forest land managers on public and private lands alike. Industrial forest management has generally been distinguished by a much higher rate of intensification than has been the case on public lands. Whereas public land management has characteristically balanced timber and non-commodity forest production. Industrial plantation establishment has been dominated by profit maximization and cost reduction through economies of scale. Forest companies are now facing the challenge of scheduling spatially specific timber management activities over time to achieve their traditional objectives and the new environmental goals.

A good operational harvest schedule will satisfy the customers’ orders from areas of forest while minimising transportation costs. Also, areas of the forest with high quality trees will be used to provide high quality (high value) logs while lower quality areas will fulfil low quality (low-value) demands, minimising the conversion of high quality trees into low-value logs. Operational harvest scheduling can be very difficult. Good operational harvest scheduling is an activity where large immediate financial gains can be found. This is in contrast to tactical planning where gains will be seen in two to three years, or strategic planning with gains realised thirty or more years in the future. The immediate gains of a good harvest schedule are listed below. Harvesting costs are reduced, harvesting productivity is increased, larger volumes of high quality logs are produced and transport costs are lowered. Harvesting is done by two means as thinning and clear cutting. The conducting silvicultural system and the economics and demand are important factors when scheduling the harvest. There are commonly using harvesting systems as clear cutting, shelter wood, selection and coppicing. Clear cutting is where all of the trees in a stand are removed. Clear cutting diseased or insect-infested area  is often necessary to protect healthy trees. Shelter wood System is designed to remove certain trees and establish new growth under the protection of an over story of foliage. Sufficient mature trees are left standing to shelter the site until new growth is well established. The using silvicultural system depends on the objective.If a site is maintained to get timber and to maintain aesthetics selection is used. Coppicing is used when fuel wood is gained. If the prime objective is to get timber, clear cut is the method which will be practised.

The rotation is also an important consideration in harvest scheduling. It helps in deciding when to harvest the stand. There are main rotations used in commercial forestry which can be stated as technical rotation, biological rotation, income generation rotation and etc. Technical rotation is suitable for providing timber, wood with specific dimensions. In biological rotation the maximum volume production is expected. The stand is harvested when maximum mean annual increment is reached. Income generation rotation is a monetary rotation where the harvesting is scheduled at the time where highest average income is gained.

Replanting of a harvested site is an important managerial activity which depends on on social, cultural, economic and environmental reasons. Use of the same species or different species is a choice made by the management. When replanting is carrying out proper silvicultural practices should be maintained to gain the final harvest such as nursery establishment and maintaining, establishment of pits for planting, spacing, block wise replanting ,weeding , fertilising, irrigation, thinning and pruning. Intercropping can be practised based on the objectives.

In Sri Lanka some upcountry Eucalyptus plantations are clear-felled and replanted with more suitable Eucalyptus species. Some selected mature Pinus plantations too are clear-felled and replaced with, Khaya, Hora, Eucalyptus and Mix species. Dry Zone Teak plantations are re established mainly with Teak in the second rotation. However in the areas where elephant damaged is high, Khaya was planted instead of Teak.

Carbon sequestration potential of a plantation will be an added benefit and when scheduling harvest the area leaving for conservation and proper practices of harvesting should be planned.

Role of Conservation Perspectives in Commercial Forestry

Presented by

Samurdi Dias

Commercial forestry aims obtaining maximum production of timber, fuel wood and other forest products as a business. Even though it aims on maximum benefits, conservation is also a major requirement. Conservation is the “practice of planning and maintaining forest areas for the benefit and sustainability of future generations”. It is important because forests provide versatile ecosystem services such as hold water, prevent erosion, ensure quality of surface and groundwater, High carbon reserve, clean the air, protection from storm damages, as a buffer against desertification, produce food, offer recreational possibilities, improve mental well-being and protects biodiversity. Also conservation is important to preserve natural beauty, increase recreational value, provide additional income sources, increase total economic value, for social benefits, to get forest certificates.

Forest Stewardship Council (FSC) is one of the major forest certification bodyin the world. FSC certification ensures that products come from well managed forests that provide environmental, social and economic benefits. It provides benefits such as access to new markets and there are 10 FSC principles; Compliance with laws and FSC Principles, Tenure and use rights, Indigenous peoples’ rights, Community relations and worker's rights, Benefits from the forest, Environmental impact, Management, Monitoring and assessment, Maintenance of high conservation value, Plantation. Principle 3, 5, 6, 9 are related to conservation. Principle 9 tlaks about high conservation value forests, which can be defined as the forests possesses one or more of the following attributes. forest areas containing globally, regionally or nationally significant concentrations of biodiversity values (e.g. endemism, endangered species) and / or large landscape-level forests, forest areas that contain rare, threatened or endangered ecosystems, forest areas that provide basic services of nature in critical situations (watershed protection, erosion control), forest areas fundamental to meeting basic needs of local communities and/or critical to local communities' traditional cultural identity.

Conservation can be done by sustainable forest management. Seven thematic areas of sustainable forest management are extent of forest resources, biological diversity, forest health and vitality, productive functions and forest resources, protective functions of forest resources, socio-economic functions and legal, policy and institutional framework. 

Other practices are less-destructive methods of logging such as make a forest inventory and map prior to logging, use of less impact machinery in logging, reduce machine operating time, train loggers in proper logging techniques, exclude clear cutting. Establishing stream buffer zones and watershed protection areas, specially design roads for transport, use fertilizer and pesticides in less harmful manner, protect fire prone areas, combined plantations, protect wildlife and nature based tourism.

Conservation practices use in Sri Lanka; in up country of Sri Lanka there is no complete removal of vegetative cover in site preparation, arrange roads along contours, avoid uprooting plant species which help to prevent soil erosion (Eg: Mana), Pine and Eucalyptus tree felling is prohibited. In intermediate zone no tree felling in some of the plantations due to water quality issues.

Another method is nature based tourism this is currently practiced in government Khaya plantation in Sigiriya. Part of the plantation is giving as camping site for tourists. The land was leased to private owner under 30 year agreement and the owner pays rental for forest department. This has high demand from tourists due to high recreation value.

Practical issues of conservation in commercial forestry are high demand for timber, illicit felling, lacks of knowledge about conservation and its importance and less concern on conservation.

Recommendations to improve conservation are law implementation, offer income tax benefits to owners of plantations, offer insurance scheme for plantations, Carbon trading, introduce value addition methodology for plantations, develop ecotourism activities in plantations located in areas like Nuwara Eliya, Knuckles, Kanneliya as there is high aesthetic value and urge private forest plantations to do conservation activities.