Timber Research and Technical Training Centre Report

Cheng, J.S.K., Mamit, J.D. and Nibu, A.N. 1985 Strength Properties of Dipterocarp Timbers of Sarawak
The mean values and the coefficients of variation (CV) of the strength characteristics of 16 Dipterocarp timbers of Sarawak are presented. The strength values are expressed in SI Units. Although the values may not be the absolute averages, they are the best available estimates. Variability is assured since the specimens of each timber were obtained from several trees collected from different parts of the State.

Mamit, D.J., and Yang, M.C. 1985 Structure and Identification of Dipterocarp Timbers of Sarawak
The general characteristics and macroscopic structure of 17 Dipterocarp timbers are described. The structure is based on 10X magnification. A dichotomous key for identification of the 17 timbers is presented.

Lim, N.P.T. and Pek, Y.K. 1985 Preliminary Evaluation of the Effect of Xylocarpus granatum on the Pulping Quality of MLH Export Woodchips from Kuala Rejang, Sarawak
The effect on the pulping quality of a composite MLH woodchip mixture with and without the inclusion of Xylocarpus granatum, which has poor pulping and papermaking properties, is investigated. The results of the preliminary evaluation are discussed and compared with that of commercial export woodchips from Australia.

Mamit, J.D., Wee, H.B. and Lai, C.J. 1985 A Survey of the Disposal of Woodwastes by Sawmills In Sarawak
A survey was conducted on 43 sawmills to determine the quantity and the disposal methods or utilisation of wood wastes produced in Sarawak. The total volume of wastes produced by the 43 sawmills in 1983 was 421, 649 m³. The disposal methods or utilisation differed from mill to mill. Most of the wastes was disposed off in a manner tending to increase environmental deterioration.

Ling, W.C. and Mamit, J.D. 1986 Timber Preservation In Sarawak
Although wood-destroying organisms are abundant in Sarawak, treated timbers are not popular among users. There are seven pressure treatment plants in the State and most of them are not operating due to an overly poor demand. On the other hand, naturally durable timbers are still abundant. About 80% of the utility timber species belong to Dipterocarps and most of these species are difficult to treat. The treatable timbers belong to the lesser-known species.
The per capita annual wood consumption in Sarawak is 0.013 m³ in 1984.

Ling, W.C., Lai, J.K. & Wong, T.C. 1986 Utilisation of Secondary Forests Species for Pepper Posts
Traditionally, Belian (Eusideroxylon zwageri) is always used as pepper posts. Uncertainty of supply has prompted researchers of TR & TTC and Agriculture Research Centre to investigate the possible use of pole-size secondary forest species, treated with CCA preservative. The results were encouraging. Many secondary forests species could be used, and the cost for collection and preservative treatment for each post averaged $4.70.

Mamit, J.D. 1986 Sarawak Timbers for Housing Construction
Selection of the right timber species for any particular purpose is always a problem for people who are not conversant with the wide range of timber properties. In housing construction, the main considerations, insofar as designers and builders are concerned, should be strength, durability, nailing property, machining and finishing properties, dimensional stability.
A list of Sarawak timbers is drawn up in respect of each of the above considerations, whereby each of the species listed is categorised or classified in accordance with its manifested quality or suitability for use.

Mamit, J.D. and Yang, M.C. 1986 Grouping of Red Meranti Timbers in Sarawak
Fifty-five Shorea species currently identified under Red Meranti are grouped into Alan, Melantai, Dark Red Meranti, Light Red Meranti, and Red Selangan with the aim of eliminating the profusion of colour variation and density range. Such grouping would facilitate marketing of sawn timbers of these species, especially in E.E.C. countries.
The grouping exercise is based on the criteria of colour, density, texture, and other macroscopic features. The general characteristics of each group are described and an identification key is also included.

Mamit, J.D. and Foo, E. 1987 Kiln-Drying Schedules of Some Sarawak Timbers
Through extensive kiln-drying tests of various species of Sarawak timbers at Timber Research and Technical Training Centre, Kuching, 10 kiln schedules are recommended. For an experienced kiln operator, these schedules can be modified to suit his operations. Of course, the main objective of modification is to minimise or eliminate drying defects in consonance with the final use of the material. Drying defects can also be prevented by following proper stacking procedures during kiln drying.

Mamit, J.D., Wee, H.B. and Lai, C.J. 1987 The Production of Lump Charcoal in Sarawak
Lump charcoal is produced in a beehive-type kiln in Sarawak from only the mangrove species. It takes about 40 days to produce the charcoal of satisfactory quality. The production of charcoal in the State is declining probably because of the depletion of raw material. Since charcoal is an important source of fuel, perhaps an improved appearance and efficient production method may attract consumers. The compressing of wood wastes like sawdust and shavings may be feasible in view of the tremendous quantity of such wastes in Sarawak.

Mamit, J.D. 1987 Utilisation of Timber for Housing Construction in Sarawak
Timber houses are not popular especially in urban areas in Sarawak, because laymen and even some professionals regard timber as a homogenous class of construction material like steel and concrete in designs and construction; consequently, timber members perform poorly in housing.
The ease with which timber is used in housing depends upon the practical knowledge of its cellular structure and properties. Thus, the discussion on the chemical composition and structure of cells and the properties should offer a useful guide to designers and builders in Sarawak.
The findings of a cost comparison study between building an all-timber house and a terrace brick house based on Peninsular Malaysia experience, favours timber. The gist of these findings should also be applicable to Sarawak.

Mamit, J.D. and Cheng, J.S.K. 1987 A Guideline for Specifying Timber in your House-Building Contract
Timber, unlike steel or concrete, is not a homogenous material. Therefore, it has to be specified differently in a house-building contract. In this report, we discuss and recommend a six point specification scheme to follow when specifying timber. The six-points are (1) timber grades, (2) timber dimensions, (3) strength groups, (4) durability and preservative treatments, (5) moisture contents of timber in service, and (6) manufacture and shrinkage.

Mamit, J.D. and Yang, M.C. 1988 Identification Keys for Logs belonging to Fifty-Seven Commercial Timbers of Sarawak
As Sarawak exports about 90 percent of its annual production of logs, it is of utmost importance that logs must be correctly identified to maintain satisfactory pricing. The State Government of Sarawak also requires that logs be properly identified because different rates of royalty and excise are levied on different species. The present standard of log identification in the logging industries in Sarawak is far from satisfactory. It is hope that the keys presented in this publication for fifty-seven commercial timbers will greatly assist those involved in logging activities and consequently, improve the level of log identification in the State.

Mamit, J.D. and Nibu, A.N. and Atok, J. 1988 Recommended Timber Species for Carving in Sarawak
Forty Sarawak timbers have been found to possess characteristics suitable for carving. It is by no means an exhaustive list because work in this area of research is continuing at Timber Research and Technical Training Centre. More timber species are being studied and information on the other species will be released from time to time.

Ling, W.C. 1990 A Guide to Preservation of Timber for Building Construction
A simplified description of wood and wood preservation is presented so as to enable architects, engineers, builders as well as house-owners to appreciate the value of wood preservation and make better use of the facilities available for wood preservation. Treatment processes in relation to commodity classes and wood preservatives are discussed. The role of wood destroying organisms, soil treatment and remedial treatment in timber preservation are also considered. Sarawak timbers can be classified into treatability classes and proposals are made on improved timber utilisation using data on treatability. Special attention is drawn to species which are extremely difficult or easy to treat. Proposal is made to use the designation "water resistant timber" for timber species which are extremely difficult to treat and recommendation is made on conservation of these species. The views and recommendations expressed by the author are based upon personal observations on wood protection industry in Sarawak as well on data obtained from research conducted at TRTTC over the period 1975-1990.

Salang, A.T. and Duju, A. 1992 An Assessment of Mixed Light Hardwood (MLH) Grouping in Sarawak
The production and export volume of MLH logs is second to Meranti in Sarawak. From the survey carried out, the species composition of the MLH logs, production and export, and the market values for each species are assessed, highlighted and discussed. While 10 species have established their markets, another 24 species have found their ways to certain countries which offered them good prices. Suggestion is made to review the term MLH as it is misleading and confusing. Suggestions are also made to review the criteria for determining the royalty classes imposed on different MLH species, and to look into a proper marketing strategy on the MLH species, so that both the government and timber trades benefit from the trade.

Hiroshi Sumi, Ismail Bin Sulaiman, Foo, E.P.L. and Tan, J.L. 1995 Kiln Drying Properties and Kiln Drying Schedules of 9 Species of Sarawak Timbers
A simple and effective method, originally designed and developed by Forestry and Forest Products Research Institute (FFPRI), Japan, known as Quick Drying Test for estimating the kiln drying schedules of unknown or lesser known species of timber, was introduced in this paper. In the Quick Drying Test, the drying properties for nine species of Sarawak timber were roughly analyzed, and their suitable drying schedules of 1 inch thick timber were estimated. Only one out of the nine species was further investigated by way of Drying Test so as to examine and ascertain the suitability of the estimated schedules derived from the Quick Drying Test. All drying schedules obtained in this study were presented by using the patternized schedule code devised by FFPRI.

Ling, W.C. and Cookson, J.L. 1996 Laboratory Study on The Natural Durability of Sarawak Timbers Against Marine Borers

Jenang, K., Inoue, M., Lai, J.K. and Ling, W.C. 1997 A Preliminary Evaluation of Incising Technique in Enhancing Preservative Penetration of Refractory Species of Sarawak
Eight refractory timber species were incised prior to being treated with 10.0 percent of Copper-Chromium-Boron preservative solution, using Bethell process. Effectiveness of incising techniques was evaluated by comparing the percentage of area penetrated by the preservative between the incised samples and the control as well as measuring relative preservative penetration of the least penetrated portion of the sample. Although there was general improvement in preservative penetration for all species, none of the species could be treated to meet the Japanese Agricultural Standard (JAS) or Malaysian Standard MS 360 : 1991.