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 Timber

Presented by

Piyali Dias

World timber market is mainly based on primary timber products such as industrial round wood, sawn timber, wood based panels, paper, paper board and wood pulp. Moreover furniture and builder’s wood work and joinery also play an important role in the world timber market. United States, Canada and the Russian federation are the leading timber producers in the world who makes the largest contributions to the global timber production which is more than 3.4 billion m³ annually. However, more than half of this timber production is gone for wood fuel while the rest of the amount used for timber and paper products where the Europe and the United States act as the world leading timber consumers. According to the recent findings the most demanded timber product was softwood industrial round wood which was produced more than 400 million m³ of timber in the year 2013 in North America. However the highest softwood roundwood flow is going from New Zealand to China where China acts as the main importer of many timber products. Though the tropical timber market is much lower than temperate timer, industrial round woods are the most demanded item among those tropical timber products. The second most demanded item was softwood sawn wood which had a production as well as a consumption of about 96 million m³ in 2013 which was recorded from the European Union. However the wood base panels, paper, paper products and wood pulp have comparatively lower demand in global timber situation where Europe dominate the production of those products in year 2013. Among those products, particle boards have the highest production which is nearly equals to the 35.5% of the total wood based panel production. Moreover the most demanded secondary processed timber product was furniture which had recorded more than $124 million by value in the European Union flowed by the US, Italy and Germany. World furniture production is dominated by Asian countries where China appears as the highest furniture producer in the world. Sawn soft woods are the main exported product which leads the world timber exports in 2013. The Europe was the all-round exporter in each and every type of timber product including round wood, sawn wood, paper, paper board, wood pulp and wood based panels. European exports are increased by 5.6% in 2013 with 46 million m³ by volume of sawn softwood exports to the overseas markets mainly to China and North African countries. However, though the prices of timber products are slightly changing from country to country the highest market prices were recorded for paper and paper boards which is around $ 900 per metric ton while the least prices were recorded for industrial round wood as nearly $ 100 per cubic meter throughout the time period of last fifty years. In temperate region, Hem Lock, Pine, Cypress and Swedish spruce are the main traded timber species while Shorea, Dipterocarpus, Teak and Ceiba leading the tropical timber market. Though Sri Lanka is not playing any important role in the world timber situation by not exporting any timber product instead of re exporting treated, imported Kempus timber by STC while private sector is involving in exports up to some extent. But here they have to overcome some of the legal barriers such as Forest act, Import Export act and Customs act as well as some international standards which set up by world reputed certification systems such as Forest Stewardship Certification, when entering to the global export market.

Species Selection in Commercial Forestry

Presented by

Tharani Dilshara

Selection of species is important in starting a plantation project because the species selected decides the affected silvicultural practice and the management and utilisation of crops.

Selection of a tree crop for planting depends on the purpose, the species potentially available for planting, site qualities, silvicultural and economic factors. Before considering the site characteristics and demands, it is essential to have clear understanding of the objectives of raising the particular plantations and those factors will narrow the choice of a species. Species selection in commercial forestry is mainly determined, however, by the demand and establishment costs.

As a rule, where a native species meets the need there is no reason to choose an alternative because of the conservation purposes more prefer the native species. However, the majority of successful plantation in the tropics consist exotic species.

Species and provenance trials have to be carried out before establishment of plantations using new species. Site qualities play a major role in the interactions between genotype and environment. Site quality factors such as climate, soil, physiographic and biotic factors affect the growth at different manner even for the same species. Another major determinant of species selection is the specific silvicultural requirement of the tree species. Having matched species to the site, a further vital decision is selection of the most suitable provenance.

In Sri Lanka the main plantation species are Teak, Eucalyptus (Eucalyptus grandis) and Mahogany. Most of the fuel wood, miscellaneous hardwood and teak plantations are located in the dry zone, Eucalypts and Pine plantations are mostly in the up country wet zone and Mahogany plantations are situated in intermediate and wet zone.