Investigation of the Effect of Growth Rate on the Quality of Teak (Tectona grandis L.f.) Wood

Teak was established as a plantation species since 1680 in Sri Lanka. Recently several private sector companies have involved in planting teak with shorter rotation. This study was designed to study how wood quality of teak varies with fast growth rates.

Based on diameter at breast height and total tree height, three different crown classes namely, suppressed, co-dominant and dominant were selected from a 45-year-old state plantation at Melsiripura, Kurunegala. Three trees from each crown class were studied. Sample disks were extracted at breast height from each tree, to measure ring width and specific gravity of each ring. Percentage heartwood was also measured.

The mean ring width values obtained for suppressed (2.65 mm), co-dominant (3.54 mm) and dominant (4.67 mm) crown classes were significantly different. Ring width values indicate the growth rate. Mean specific gravity values obtained for these classes (0.6231, 0.6473 and 0.6346) were not significantly different. Specific gravity is a measure of wood quality. Regression coefficients between ring width and specific gravity were very low: in suppressed R2 = 2.1%, in co-dominant R2 = 0.0% and in dominant R2 = 0.0%. These results show that the differences in specific gravity in the crown classes cannot be explained by the differences in growth rate, indicating that there is no relationship between growth rate and specific gravity. Based on these results it can be concluded that ring width is a property that depends on the growth rate but specific gravity seems to be an inherent property independent of growth rate variation. Hence, fast growth rates with shorter rotations will not likely to reduce specific gravity in teak.

Wood property patterns were found similar between the crown classes, indicating that these trends are inherent in teak. Ring width fluctuates close to the pith, and then decreases forming almost a constant value towards the bark; specific gravity remains almost a constant value from pith to bark.

D.N. Jayawardana and H.S. Amarasekera

Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka

Recent Trends in the Forestry Sector of Sri Lanka

Mr  H  M  Bandaratillake
Director, Forest Resources Management Project
Ministry of Environment & Natural Resources

The forest cover in Sri Lanka has been continuously declining during the last several decades.  The forest cover which was around 44% of the land area in 1956 had declined to 23.9% in 1992 and 22% at present.  It has been widely accepted that this rate of deforestation has caused one of the main environmental and social problems in the country.  Although, successive governments have taken many steps to conserve forests and to introduce laws and regulations to control deforestation, the problem was aggravating from year to year without effective solutions, mainly due to the conflicting demands placed on forest resources.

In view of this situation, the National Forest Policy was revised and Forestry Sector Master Plan  (FSMP) was formulated and approved by the government in 1995.  The Forestry Sector Master Plan (FSMP) which was based on the National Forest Policy, provides the framework for developing partnerships with non state sector for promoting community and private sector participation in forest conservation and development. FSMP also provide a guiding framework to introduce new policies and to carryout legislative, administrative and institutional reforms required.

The Forest Resources Management Project (FRMP) which is scheduled to implement during 2001- 2007 is the first implementation programme of the FSMP. The overall objective of the FRMP is to establish and operationalise participatory sustainable forest resources management for increasing forest protection and production. With the implementation of  FRMP, number of new strategies and programmes have been introduced to the forestry sector in order to achieve the objectives of sustainable forest management.  Some of these strategies include;  private sector re-forestation and management, woodlot development, establishment of Permanent Forest Estate, Re-organisation of the Forest Department, Amendments to the Forest Ordinance, Private sector harvesting of forest plantation and development of nature tourism etc,.  Legal provisions including mechanisms for benefit sharing have been provided to facilitate the effective implementation of these programmes.

Theme Seminar Presented at Forestry and Environment Symposium 2005, Organized by Department of Forestry and Environment Science, University of Sri Jayewardenepura, December 2005, Thulhiriya, Sri Lanka

Investigation of ergonomic parameters of easy chairs in Moratuwa furniture manufacturing establishments

S A L P Silva and H S Amarasekera
Department of Forestry and Environmental Science,
University of Sri Jayawardenpura, Sri Lanka

Sitting on a comfortable seat helps to relax the body and reduce energy consumption, but on the other hand prolonged sitting slackens abdominal muscles and may cause back ache. Application of medical and ergonomic principles in the design of a seat can maximize advantages and minimize disadvantages in sitting.

In Sri Lanka the demand for a furniture depends on the customer perception to comfort and beauty of the product. The present study aimed to find out whether the easy chairs manufactured in the Moratuwa Furniture Manufacturing Establishments were ergonomically designed for the Sri Lankan users.

The investigation was initiated with the identification of easy chair designs in the Moratuwa Furniture Manufacturing Establishments. A representative sample of two popular easy chair designs, the Kulu Putuwa and the Medal Putuwa, was then selected. The different design parameters of these two chairs were measured. It was observed that there were differences in the dimensions of the major design parameters of the chairs between companies.

Sri Lanka has no specific standards for designing of furniture. Hence design standards were developed for easy chairs in the present study based on available anthropometric data for Sri Lankan users and other published anthropometric data on seat designs.

The different design parameters of Kulu Putuwa and Medal Putuwa were then compared with those developed ergonomic standard values. It was observed that only the back rest height of the easy chairs was ergonomically acceptable in all the companies surveyed. Seat height, seat depth, seat width and arm rest height were lower than the accepted standard values. Such improper dimensions should result in discomfort and body pain. The angle of rake and angle of tilt, which indicate the inclination of the back rest, were significantly lower in the sampled chairs. The inclination of the back rest was lower than the required 1150-1200, which should result in low back stress and static muscular tension, which may lead to development of back injuries.

In order to improve the ergonomic parameters of the Medal Putuwa, a prototype chair was designed. Seat height, seat depth, seat width, arm rest height, of the prototype char was lower and it had higher angle of tilt and angle of rake. The designed prototype chair was evaluated against a normal control chair, and the users rated the ergonomically designed chair was much better compared with the control in terms of comfort.

The present study reveals the need for Sri Lanka to have specific standards based on the body sizes of users, for design of furniture. This will enable the production of ergonomically correct and aesthetically acceptable quality furniture in Sri Lanka.