Major insects attacking timber used for building purposes and a practical approach for their control

IRG/WP 1449

V R Sonti, B Chatterjee

Lignocellulosic materials like wood, bamboos, palmyra palms, reeds, leaves and grasses have been the oldest materials used by human beings. Although with the rapid pace of industrialisation, specially in several western countries, wood began to be replaced with alternative materials like cement, steel etc. yet its use has not vanished even in highly developed countries. Some of the reasons for this are its inherent advantages over other building materials. Wood is a renewable resource, economical in use, easy to work with and process and possesses adequate strength. In addition, it has better thermal, electrical and accoustic insulation properties and can withstand fire resulting in lesser damage to buildings. In developing countries, like India, where resource exploitation has not kept pace with rapid population growth, the use of wood in building construction has dwindled in preference to alternative materials due to certain reasons like:- (i) use of cement, steel, etc. is regarded as a symbol of industrial advancement, (ii) naturally durable species are becoming scarcer and costly and (iii) lack of knowledge amongst consumers, engineers, designers regarding processing techniques, scientific designing of wooden structures, choice of suitable species according to strength etc. The component of wood varies from 10-15 percent of the total building cost (1) Presently it is reported that nearly 3 million cum. is utilised for building construction which is likely to increase in the near future (2) as there is a shortage of the order of 6 million urban and 18 million rural units. At several recent International consultations on the utilisation of wood in buildings, it has been emphasised that wood, as a constructional material, has not been receiving adequate attention in the training programmes of architects and engineers and that there has been a complete neglect of the large technological potential that exists for replacing solid wood by plywood, particle board, wooden board etc. Introduction of proper processing techniques, careful selection of species for the end use, proper grading practices, reduction of presently permitted safety factors through mechanical grading and improved designing and timber engineering, progressive adoption of re-constituted wood products can lead to considerable savings of wood. The ill organised state of sawmilling industry in most of the developing countries restricts investment potential for essential operations - processing, grading, design development etc. Conversion of timber in advance and stocking of graded and processed sizes and prefabricated components is not possible when units operate in a very small scale and in widely scattered locations. Lastly, sufficient education and confidence in the feasibility of timber structures are yet to be developed amongst consumers, engineers, architects and manufacturers. Apart from timber other forest based materials like bamboo, thatch grasses, leaves, reeds etc. for rural housing cannot be ignored specifically in developing countries like India, where bulk of the population lives in villages and uses these materials without processing. While several problems in the introduction of scientific processing of building materials of lignocellulosic origin, including reconstituted wood, arise due to socio-economic factors and organisation of the industry, the need for research to develop simple and economical processing techniques cannot be ignored for any developing country. It may, however, be pointed out that in India there is already enough data base on properties and working stresses of timbers, seasoning and preservation processes, timber engineering designs, use of reconstituted wood etc. Some of these aspects are briefly highlighted here.


Conference: 90-05-13/18 Rotorua, New Zealand

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