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A discussion on causes, effects and remedies of arsenic pollution of groundwater in Bangladesh
1998 - IRG/WP 98-50102
This paper includes possible causes, effects and remedies of arsenic pollution of groundwater in Bangladesh, extracted mostly from the international conference held in Dhaka in 1998. Next possible key steps have been suggested based on scientific principles and experience. The release of arsenic from underground sediment would be due to excessive mechanical forces, geochemical and geobiological reactions. Arsenic free water will cure acute patients and will save future generations. Use of suitable organic chemicals, organic matters, biological control system would be widely acceptable for supplying arsenic free water. Other natural sources of water can be used easily and safely without mechanical and chemical processes. The problems of chronic patients would be solved genetically, enzymatically and nutritionally.
A K Lahiry


Rational weight per weight (w/w) qualifying retention from a pole bank in Bangladesh
2000 - IRG/WP 00-40187
Weight per weight (w/w) vs weight per volume (w/v) retention study revealed that the w/w % retention is found to be appropriate and uniform for all timber species in respect of its real effectiveness. The pole species having density below 512 kg/m3 (32pcf.) showing w/v retention below 20kg/m3 (1.25pcf.) have equal w/w retention of 4%. The apparently reduced w/v retention of low density poles will be compensated/adjusted by total additional preservative required for higher dimension of poles compared to standard US origin southem pine poles (Pinus elliotti, P. echinata, P. taeda, P. palustris) required to satisfy desired bending load. The pole species having density higher than 512 kg/m3 (32 pcf.) will also give real equal w/w retention of 4% by showing higher w/v retention. About double w/v retention will be required for Bangladesh orgin sundri (Heritiera fomes) or equivalent pole species which is very essential for higher service life compared to softwood poles. In softwoods cell wall can be completely penetrated with CCA to protect soft rot fungi but such function in dense hardwoods may be carried out by additional retention. Remedial treatment is found to be the vital issue for hardwood pole for long term satisfactory use in contact with ground even with possible higher retention of w/w 4% or above. Dual treatment (CCA-C + creosote) is another solution for adequate service life of hardwood poles.
A K Lahiry


Penetration analysis of two common bamboo species - borak and jawa of Bangladesh
2002 - IRG/WP 02-40247
Preservative treatment of two bamboo species, namely borak (Bambusa balcooa Roxb.) and jawa (Bambusa salarkhanii Alam) was carried out with chromated copper boron (CCB) preservative by dipping method. The variation in preservative penetration between the two different species was determined. It was found that preservative penetrates into borak quicker than into jawa and easier into air-dried bamboo than into green one.
M O Hannan, A K Lahiry, N M Islam


Accelerated fixation of CCA in borak bamboo (Bambusa balcooa Roxb.) of Bangladesh
2001 - IRG/WP 01-40193
CCA-C fixation study on impregnated (6% CCA solution), then boiled, oven-dried, normal, air-dried and steamed bamboo slices of air-dried borak bamboo (Bambusa balocca Roxb) of Bangladesh, revealed almost complete fixation in steamed (accelerated fixation) and air-dried (3 weeks, slow fixation) bamboo slices compared to moderate to slow fixation in boiled, oven-dried, normal and 24h air-dried slices.
A K Lahiry


Marine borers as wood degraders in Bangladesh and their protection
1996 - IRG/WP 96-10186
Field study on timber piles used in Bangladeshi brackish waters revealed that untreated and pentachlorophenol treated piles drastically degraded by the attack of molluscs and pholads (marine borers). Adequately CCA-C impregnated (30 kg/m³ or 6% W/W dry oxide retention) timber piles can protect the attack of molluscs. It is very difficult to protect pholads which can invade naturally very durable timbers. Adequately preservative treated piles can be protected from pholads by hardening the initial surfaces by noncorrosive metal plates or by cement. Use of only dense and hard timber species would be a solution.
A K Lahiry


Chapter 2 - Introduction to world bamboo
2007 - IRG 07-10635-02
In this chapter the bamboo species of the whole world along with local name, bamboo type, flowering type, locality and uses have been presented in 20 different Tables.
A K Lahiry


An introduction to environmental aspects of groundwater arsenic and CCA treated wood poles in Bangladesh
1997 - IRG/WP 97-50081
The environment comprises biosphere, lithosphere, atmosphere and hydrosphere. Therefore, environmental science is a multi-disciplinary study, includes life sciences, physical sciences, chemical sciences, geology, geography, meteorology, forestry, agriculture, soil science, hydrology, ecology, public health, engineering etc. Tremendous industrial and mining activities, deforestation and population explosion are threatening the very existence of life on earth.Groundwater is used for irrigation, drinking and other domestic purposes where other sources of water are not plenty. Groundwater contain different metals resulting from soluble minerals, deposited in ground during its origin. Thus concentration of metals in surface soils and water are increased day by day by lifting of groundwater. Surface soils and water also receive metals from industries and mines and as a result of multipurpose use of products from those. Deforestation is controlled by plantation and preservation of forest products by different wood preservatives. Recently groundwater in some underground rocks of Tertiary and Quarternary age in Bangladesh is very often known to contain arsenic (As) above permissible limits . On the other hand chromated copper arsenate (CCA) impregnated wooden poles has been used for rural electrification in Bangladesh since 1979. It is an attempt to find out through research and review of literatures that whether the groundwater As is contaminatable from As used in wood poles and whether the components of CCA cause environmental problems. Possible way of purification of arsenic containing groundwater for drinking have been suggested.
A K Lahiry


Physical and mechanical properties of a suitable constructional timber of Bangladesh
1997 - IRG/WP 97-40102
The study of physical and mechanical properties of lohasirish timber (Derris robusta Roxb.) grown in Bangladesh revealed that the sapwood is whitish to yellowish white, heartwood is dark grey to blackish in colour; the texture is moderately fine, the grain in mostly straight and coarse with whitish rings of parenchyma; shrinkage is moderate; the EMC ranges from 12% to 16%; fuelwood colorific value is higher; workability is moderately difficult but suitable for constructional works; the wood is heavy, the density is 750 ± 5% kg/m3 and 134% of Bangladesh teak (Tectona grandis); the sapwood is perishable and heartwood is moderately durable to durable; kiln-drying is moderately difficult to difficult; sapwood is easily pressure treatable but heartwood is refractory to treatment. The modulus of rupture (MOR) at green condition is 70 ± 2% N/mm2 which is about 100% of Bangladesh teak. The timber is very suitable for all constuctional and structural uses including electric anchor logs, crossarms and railway sleepers, beams, door frames etc.
A K Lahiry


Adequate preservative treatment of tropical and subtropical hardwoods for electric anchor logs
1997 - IRG/WP 97-40101
Most available 27 different hardwood species grown in Bangladesh was investigated regarding suitability as CCA-C (chromated copper arsenate type-C) impregnated anchor logs for rural electrification programme. The kiln-drying properties, sapwood thicknesses, CCA treatability grades of sapwood and heartwood, natural durability of heartwood and CCA retainability at specific assay zone separated 27 hardwoods into two different treatment groups A and B. The logs of both the groups were full cell pressure treated at initial vacuum of 600-700 mm Hg and at impregnation pressure of 14-18 kg/cm2. The logs are equivalent regarding service life. The treatment group A includes 7 species, characterized by pretreatment moisture content of 15%, thin sapwood thickness of at least 25 mm, high natural durability and refractory to treatment of heartwood, penetration requirement of at least 25 mm plus 100% sapwood with treatment grades of 75% (+++) and retention requirement of 20 kg/m3 dry oxides in an assay zone of 5-25 mm. The treatment group B includes 20 species, characterized by pretreatment moisture content of 20% thicknesses of sapwood and treatable wood equivalent to at least 44% of radius of logs, low natural durability of heartwood, penetration requirement of at least equivalent to 44% of radius of logs plus 100% sapwood with treatment grades of 75% to 100% (+++ to ++++) and retention requirement of 20 kg/m3 dry oxides in an assay zone of 12-50 mm.
A K Lahiry


Treatability and retainability of two important bamboo species - borak and jawa of Bangladesh
2002 - IRG/WP 02-40248
Preservative treatment has been carried out with five different concentrations, i.e. 3%, 4%, 5%, 6% and 7% and durations, i.e. 2 days, 4 days, 6 days, 8 days and 10 days, at different moisture content, i.e. green and air-dry, and different direction of penetration, i.e. radial and both radial and cross-section for jawa and borak. It has been observed that retention of CCB is always higher in jawa bamboo than borak, which is a clear indication to consider jawa bamboo a more permeable and diffusible bamboo species for dipping process. Adequate retention of preservative for indoor use has been obtained in most of the cases. It has been observed that 6% concentration of preservative with 8 to 10 days duration of dipping provides the best results.
M N Islam, A K Lahiry, M O Hannan


Upright capillary absorption behavior of five important timbers and one bamboo species of Bangladesh
2004 - IRG/WP 04-40273
The upright or vertical capillary absorption rate of five different timber and bamboo species namely mango (Mangifera indica), kalajam (Syzygium cumini), kanthal (Artocarpus heterophyllus), sissoo (Dalbergia sissoo), mahagoni (Swietenia macrophylla) and mulibamboo (Melocana baccifera) were measured in relation to their specific gravity and duration of immersion. It has been observed that there was significant relation between increase of capillarity and timber species. From the analysis of data it was found that the rise of capillarity is more or less similar in case of bamboo, jam and kanthal but the values were comparatively lower than that of mahagoni, sissoo and mango. The value of the capillarity has been found the highest in mangowood. There was no significant relation with the rise of capillarity and advancement of time. Initially, the soaking rate of bamboo has increased at an increasing rate, but it soaks the solution at more or less same rate with time. It has been also observed that the absorption height has changed with the specific gravity of wood and absorption height has increased gradually with the increase of immersion time.
M A Islam, A K M A Bosunia, A K Saha, A K Lahiry


Physical properties variation of sound and top dying affected sundriwood (Heritiera fomes) in mangrove forest of Bangladesh
2004 - IRG/WP 04-10504
Top dying of sundri (Heritiera fomes Buch.-Ham.) in the Sundarbans is considered to be the most severe of all the diseases of tree crops in Bangladesh. The wood samples from sound, moderately affected and severely affected sundri trees from three different tree heights for every individual test were collected and their respective physical properties were examined to make a comparison. It was found that density decreased with the increase of disease severity and was found 5% for both the cases. The volumetric shrinkages also increased due to top dying and were found 6.42% and 3.34% higher for moderately affected and severely affected trees respectively. Similarly the initial moisture contents also decreased due to top dying and were found 5.34% and 16.19% lower for moderately affected and severely affected trees respectively.
S C Ghosh, A K M A Bosunia, M A Islam, A K Lahiry


Comparative study on physical properties of four fast growing timber species of Bangladesh
2006 - IRG/WP 06-10570
Ghoraneem (Melia azedarach), Rain tree (Albizia saman), Sissoo (Dalbergia sissoo Roxb.) and Akashmoni (Acacia auriculiformis) plantations are started as a fast growing timber specie from a few years back in Bangladesh. Initian objectives were to get fuel wood only from those trees, but a very positive response was found for Ghoraneem, Rain Tree, Sissoo and Akashmoni timber in the users market by cutting the trees and therefore maintaining its rotation period. The timber of these trees also attracted the furniture makers as well as general users due to its grain, texture, colour, availability and low-cost which helped to boost the commercial value of the species. This popularity and high demand of Ghoraneem, Rain Tree, Sissoo and Akashmoni timber in the market encouraged to carry out a comparative study on the physical properties of these fast growing species. The wood samples from three different heights for every individual test have been collected and their respective physical properties such as shrinkage, density and moisture content were examined to make a comparison. Ghoraneem, Rain Tree, Sissoo and Akashmoni trees showed significant difference in respect of tangential and radial shrinkage, respectively. Rain tree showed the lowest volumetric shrinkage (7,517%) and Akashmoni the highest (13,66%). Tangential, radial and longitudinal shrinkage didn’t differ significantly among the top, middle and bottom sections of a particular quality of wood. Density also differed significantly among the species. Sissoo showed the highest density (0.74 g/cm3) when compared to the others.
M M Islam, B K Dey, M O Hannan, G N M Ilias


Environmental situation on wood preservation industries in Bangladesh
2000 - IRG/WP 00-50148
The hazard that wood preservative chemicals pose to people and the environment is serious. The lack of information, legislation and awareness create an unfavorable situation on wood preservation industries. In this regard, three wood preservation industries have been visited to collect the information about pollution. It was observed that different steps have been taken to minimize the contamination created by wood preserving chemicals. But in some stages, peoples are not aware in handling the treated materials and chemicals. The techniques of conditioning to allow fixation of CCA at the treating plants are rather haphazard. Soil is contaminated due to leaching from the freshly treated materials. Government and wood preserving industries should both share the responsibility to protect human life and the environment through proper management.
K Akhter


Present status and potentiality of the economic utilization of the sawmill residue and wastage in Bangladesh
2004 - IRG/WP 04-50211
This study has been carried out to obtain a clear picture about the current status of utilization of sawmill residue and wastage. In order to accomplish the study a random survey has been conducted in 27 sawmills of Khulna District and in 10 sawmills of Jessore District. Most of sawmills in these area run at a very primitive level compared to modern technology. Species used for conversion mainly depends on the demand and availability of logs in the surrounding areas of sawmills. In Khulna and its surrounding area the daily average consumption of log is about 104.86 cft., per sawmill. Daily average production is about 62.39 cft., and 42.47 cft. Wood is wasted as sawdust, edging/trimming, slab and in other ways. The percentage of production and residue is about 59.5% and 40.5% of the total consumption of logs in the sawmills respectively and among the total sawmilling residue, edging/trimming, sawdust, slab and others constitute about 20.73%, 12%, 4.22% and 3.55% respectively. Here it has also been attempted to estimate the approximate amount of wood wasted in 4,800 sawmills of Bangladesh. About 3.34 million tones per year of wood waste is produced during conversion in which edgings/trimmings, sawdust, slabs of different inferior sizes and others are about 1.71, 0.99, 0.35 and 0.29 million tones per year respectively. The most amount of sawmill residue is being used as fuel for cooking. About 100% of edging/trimming residue is used as fuel and 60% slab is used as fuel and another 40% is used for box making. Among the total produced sawdust about 70% is used as fuel and 30% is used as other purposes like in poultry farms, as water absorbing material, in ice factories etc. But this huge amount of sawmill residue can be used for manufacturing various value-added products like particleboard.
M A Islam, M S Rahman, A K M A Bosunia, A K Lahiry


CCA treatability of 100 timbers of Bangladesh
1996 - IRG/WP 96-40069
CCA treatabilities of 100 timber species grown in Bangladesh have been compared with the treatability of Pole pine (Pinus caribaea) grown in Bangladesh which revealed new five treatability grades. Sapwood of 48% species and heartwood of 9% species was found to be treatable with CCA under grade (++++) having 100% penetration. Like softwood where CCA penetrates completely in cell lumens and cell walls effectively, the timbers under grade (++++) are usable for long term best utilization in contact with soil and water. The service life of timbers under treatability grade (+++), (++), (+) and (-) having 75%, 50%, 25%, and 00% penetration respectively would be proportionately lower if used in contact with soil and water. The heartwood of 61% timbers was found to be refractory to CCA treatment even at higher impregnation pressure (12.5-18 kg/cm²), higher initial vacuum (500-830 mm Hg) and pre-treatment moisture content of 10%. Revealed that the highest treatability was limited within whitish wood and the highest impermeability was limited within deep couloured wood (e.g. reddish, blackish, brownish etc.).
A K Lahiry


Natural durability, density and extractive contents of 42 wood species of Bangladesh.
2003 - IRG/WP 03-10490
Natural durability, density and major extractive contents of 42 lesser used or unused wood species of Bangladesh have been studied. Correlation analysis between these properties has been performed. It has been shown that natural durability of these species neither explained by water soluble nor by alcohol benzene extractive contents. Density has a weak but significant positive correlation with durability which indicates that density might have some influence on durability of these wood species.
S Akhter, K Akhter, S C Das


Performance of CCA wood preservative and CCA treated wooden materials (pole, anchor log, cross-arm etc) with special reference to Bangladesh (Series 1)
2005 - IRG/WP 05-40318
Wood is an important renewable natural resources produced by plants which is without question oldest and versatile construction material. It is composed of cellulose, hemicelluloses and lignin. Cellulose and hemicelluloses accounts for about two-thirds of the dry weight of the wood which perform the major structural role. Lignin is the remaining one-third of the wood which holds the cellulose and hemicelluloses together as a structural unit like the mortar between bricks in a house. Wood is excellent due to its unique characters and properties such as, availability, economical, easy transportation and installation, physical and chemical properties, renewability, strengths, versatile uses, density, durability, flexibility, toughness with elasticity, treatability, beauty, reusability, conductibility of heat, sound and electricity etc. In the present day, timber and timber products are widely used all over the modern world, and thus a lot of researches have been done on timber and timber products, and different technologies have also been discovered. For human livelihood, use of timber and timber products are very closely related especially to the people of third world countries, like Bangladesh. Without the use of timber and timber products the daily life of peoples of the third world countries is going to be impossible. From timber very essential products like papers, wooden frame or partition for making shelter or houses, fuel, construction of bridges, poles for electric and telecommunication lines or posts for house building, rail way sleepers, under ground pilling for civilization, furniture, packing boxes, boat and ship are prepared. Timber has a strong drawback of its short life span or durability period especially sapwood of all timber species and heartwood of some timber species. In general, some living organisms which are natural enemies of wood use it (wood) as a source of food, shelter and as a place for the incubation of their young. The wood enemies are – fungi, insects, marine animals etc. But now it is proven science that the life spans or durability of all timber species could be extended several times (40 – 50 years or more) by using preservative treatment. So, preservative treatment of wood has a grate role on the enhancement of durability of wood. Therefore, the selection of appropriate preservative is very important science. Some timber species are more capable of accepting preservative treatment than others, depending upon a number of factors such as, selection of appropriate preservative, appropriate timber species, appropriate seasoning process and appropriate treatment process. In this article selection, use and performance of appropriate preservative would be discussed. The choice of preservative was predominantly creosote or its solutions with coal tar, pentachlorophenol and copper naphthenate were confirmed as a standard preservative in 1950s. But with the first development and patent of CCA salt formulation by Dr. Sonti Kamesam in 1933 in India, use of water borne preservative was started. That time the trade name of the patented CCA preservative was ‘ASCU’. The oxide formulation of CCA was patented by Boliden AB in Sweden during 1950s. In 1950, AWPA patented oxide based CCA into two types A and B. In 1969, AWPA formulated oxide based CCA type – C. Meantime the effectiveness of CCA – C as oxide formulation is proven as the best and mostly used on good faith. CCA can protect the attack of the most unprotected soft rot fungi and can also protect wood from the attack of other decay fungi, termites, beetles, marine borers, carpenter ants etc. Protection capability of CCA depends on penetration, retention and degree of fixation in wood. Performance records of CCA (type – c oxide formulation) are the highest among all other wood preservative available. Some records of the best performances of CCA are available all over the world. CCA treated wood, wood products and poles are in service in a very high hazards areas for 70, 50, 66, 42, 32, 44, 22, and 26 years in India, United Kingdom (UK), United States of America (USA), New Zealand, Australia, Sweden, Papua New Guinea and Bangladesh respectively and expected that the treated woods will be in service for several years. CCA treated wooden poles, jetty etc are performing better than SPC and steel poles in service without any damage in brackish water as well as in normal water for last 26 years in Bangladesh.
G N M Ilias


Treatability and natural durability of some lesser used or unused wood species of Bangladesh
2000 - IRG/WP 00-40170
A research study was conducted to determine the natural durability and treatability of heartwood of some lesser used or unused wood species. The treatability of species has been studied along with certain anatomical concepts association with preservative penetrability of the wood. It was observed that grain structure and presence of tyloses appeared to be correlated with penetrability of the wood. The retention of the preservative chemicals through heartwood have been determined by ASOMA X-ray analyzer. The species were classified into four treatability groups according to the degree of heartwood penetrability which will help the user to select the proper treating process. A stake yard test on these indigenous species was carried out to determine their natural durability. Based on the result, durability classification of these timbers has been made. Depending on this group user can select the species for treatment and particular use.
K Akhter, M Younusuzzaman, M H Chowdhury


A note on te seasoning, preservative treatment and suitability of debdaru (Polyalthia longifolia Benth & Hooker.) for poles
1995 - IRG/WP 95-40056
The main work is to determining the suitability of Debdaru (Polyalthia longifolia Benth.) as poles from Government and Village forests are investigated. The poles of Debdaru are easily treatable with CCA preservative by full-cell pressure method, but difficult to dry (air & kiln). Proper quality control must be maintain from procurement to treatment, specially during physical selection & drying (air & kiln) otherwise it may be discard as pole. Debdaru poles have been found suitable for power and Telecomunication lines with very keen care.
G N M Ilias, M D Rokib-ul-Hafiz


Non leachability of arsenic, copper and chromium from 15 years old CCA-C treated southern pine poles used in brackish water as jetty piles in Bangladesh
1998 - IRG/WP 98-50103
Revealed that chromated copper arsenate type C (CCA-C) treated southern pine poles used in Central Warehouse Jetty of REB, Khulna are stable and resistant to chemical and biological attack without loss of any component from outer 0-12.5 mm zone after 15y of use. Slightly reduced retention (4.44% less) was noted in above water location of piles (bottom end of tree) which would be due to continuous weathering, torrential rain and genobiotic activities in jetty for a long time. The retention of recent southern pine poles (1.5y old) was w/w 4.17% (sd 0.0684) in 0-12.5mm assay zone compared to w/w 4.95% (sd 0. 1286) in under water location and w/w 4.73% (sd 0. 1137) in above water location of 15y old jetty piles. Such a preservative treated wood poles and piles are more safe in brackish water rather than other constructional materials.
A K Lahiry


An environmental aspect relating to leachability of CCA from hardwood and softwood poles in Bangladesh
2001 - IRG/WP 01-50167
Leachability of CCA and the service performance of 8 softwood and 5 heartwood poles in service after 5 to 17 years in Bangladesh have been studied. The study included determination of retention of CCA-C in outer 6 mm zones at groundline (GL) and above groundline (AGL) along with the observation of decay and conditions of soils. The mean leaching of CCA-C derived from retention differential at GL and AGL are not found to be statistically significant. The existing balances of CCA-C components in poles do not indicate any leaching loss occurred. Reductions in retention have been noted at GL of softwood poles and at AGL of hardwood poles. Among several possibilities the density of wood as well as wood species/types, levels of retention, conditions of soil are found to be the prime factors which may increase leaching/depletion of CCA from the GL of softwood poles and responsible for poor performance of hardwood poles. The levels of CCA retentions in hardwood poles are not found to be adequate and equivalent to the levels of softwood poles in use. The CCA retentions of softwood poles were found still well above the toxic threshold for decay in even the oldest poles. Remedial treatments at GL of CCA-C treated hardwood poles installed in Bangladesh have been found to be essential. Very good service conditions confirm no remedial treatment necessary for CCA treated softwood poles.
A K Lahiry


Preservative treatment of common timbers and bamboos of Bangladesh for rural electrification infrastructure
1998 - IRG/WP 98-40104
Researches revealed new treatment grades, treatment groups, grading groups, natural durability grades, strength groups and a new preservative combination for remedial treatment and sterilization of most common timbers and bamboos of Bangladesh. The obtained findings are applicable for equivalent timber species having equivalent climatic condition. Sapwoods are always perishable and timbers with whitish to grayish heartwood without tylosis are found to be nondurable and permeable to preservative treatment, recommended to use after preservative treatment following appropriate treatment group. Perishable to durable impermeable heartwoods can be penetrated with boron, suitable for indoor use only. CCA-C is suitable and preferable preservative for ground and water contact use rather than CCB and pentachlorophenol as the laters are leachable. Decay pattern study revealed that the service life of round timber for ground contact use is increased with the increase of adequately CCA-C impregnated (w/w 4% or 20 kg/m3 dry oxides of CCA-C) shell thickness, the preferable shell thickness shall be at least equivalent to 44% of radius (carry 90% of bending load) where remaining untreated central core is not naturally very durable. Kiln-drying with heat sterilization schedule is a key step for adequate treatment and slow drying or accelerated fixation is the post treatment effective step for higher service life.
A K Lahiry


Pole yield of some softwood and hardwood species grown in Bangladesh
1999 - IRG/WP 99-40143
Growth study on 9 timber species planted in Bangladesh soils revealed that 6 species fall under wooden electric pole yield group-A, produce 33% poles within 10 years, another 33% within 15 years and additional 33% within 20 years of rotation. Two species under yield group-B produce 33% poles within 15 years and another 33% within 20 years. One species under yield group-C produce at best 25% poles within 15 years and 50% poles within 20 years of plantation, considered to be unsuitable for pole production compared to the species under group A and B. Large scale plantation with timber species under yield group-A is recommended for pole production.
A K Lahiry


Standardization of CCA treated 45 hardwood species grown in Bangladesh for REB crossarms
1995 - IRG/WP 95-20059
Researches on 45 hardwood species grown in Bangladesh regarding density, moduli of rupture (MOR), colour and treatability of sapwood and heartwood, seasoning property and natural durability of heartwood revealed that both sapwood and heartwood of 17 species could be full cell pressure treated with CCA at impregnation pressure of 14-18 kg/cm² and only sapwood of rest 28 species could be pressure treated. Hartwood of 28 species were found to be mostly refractory to treatment but naturally fairly durable to very durable when used indoor or overhead exposed conditions. The MOR of 45 timber species varied from 58-96 N/mm² at green conditions, sufficiently strong for distribution crossarms. The most dense timbers were found to be kilndried slowly and effectively. Inherent strength, conventional sawing, conventional grading with pilodyn, kilndrying before treatment and slow air-drying before outdoor storing upto EMC (19% MC) at centerline of crossarms and adequate CCA-C treatment in treatable areas would ensure long term utilization of these timbers in Rural Electric Systems in Bangladesh.
A K Lahiry


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