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.).

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