Sundri (Heritiera fomes) poles were treated with 40 : 60 creosote and light diesel oil mixture at different pre-designed combination of treating pressure and treatment time to evaluate the response to the individual as well as combined action of these process variables. It was found that the effect of treatment time was statistically highly significant in increasing the penetration of preservative into the sapwood while the treating pressure could increase the same only significantly. On the other hand, both the treating pressure and the treatment time had highly significant effect on increasing retention of preservative in the sapwood.

The coefficient of variations of penetration and the coefficient of variations of retention within the individual poles were in the range of 2.14 to 22.56 percent and 2.15 to 14.75 percent respectively. The same for among the poles were 30 and 23 percent respectively. The variation in these characteristics of the pole, however, could not be considered disadvantageous because the penetration and the retention were directly correlated with the thickness of sapwood zone in the poles.

Seasoned Sundri pole without being subjected to any pretreatment conditioning could be treated to achieve 2.85 cm penetration and 373.22 kg/m² retention in the sapwood after using a treating schedule of 10.55 kg/cm² treating pressure and 6 hours treatment time. This amount of penetration and retention may be considered adequate for poles to be used in power transmission line in Bangladesh, as these are well above the minimum recommended in the Bangladesh Standards for penetration and retention for such use.