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.

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