This study was prompted by two considerations; first the possibility that sorted amabilis fir (commonly known as balsam) might be marketable as a more treatable wood species, and second, the need for an explanation for batches of hem-fir which are unusually difficult to treat (refractory). Preliminary studies at Forintek and elsewhere had shown that preservative penetration in amabilis fir was greater than in western hemlock. It was necessary, however, to quantify this difference and determine if it was common to the entire B.C. coastal region. Sorted amabilis fir and western hemlock from five coastal B.C. sawmills (20 boards per mill and species) was planed to nominal 2 x 4 inch dimension, cut into one short length and four end-matched sub-samples. Half the end-matched sub-samples were conventionally incised and half were double-density incised. From each group, half were CCA-treated with a three hour pressure period and half were treated with a six hour pressure period. Without incising, amabilis fir exhibited 80% deeper penetration and higher preservative retention by analysis than western hemlock. Unincised amabilis fir came close to meeting the proposed Canadian standard for residential decking. Conventionally incised amabilis fir met the Canadian standard for wood in ground contact. In contrast none of the sorted western hemlock from the five sawmills met the standard even when double-density incised and given a six hour pressure period. These results suggest that there is an opportunity for species separation to produce a treatable amabilis fir product and a higher strength pure western hemlock product. Furthermore, these results provide an explanation for the variation in the treatability of hem-fir. It appears that this is greatly dependent on the ratio of hemlock to amabilis fir. On the B.C. coast hem-fir averages 80% western hemlock and 20% amabilis fir, however, these proportions can vary from 0 to 100% in the material sampled. Refractory batches of hem-fir may simply be low in amabilis fir. Compared to amabilis fir, no other Canadian wood species can be so easily treated to the lumber standard with conventional incising. Sorting and treating pure amabilis fir would therefore result in a dramatic improvement in the ability of the Canadian wood preservation industry to meet Canadian and American standards.