Bulk bags are ‘loose-filled’ i.e. dropped into the bag from a conveyor. The logs are therefore not stacked in the bag. We know that the volume is correct as we check the volume in a metal cage measuring 1m x 1m x 1.2m or 1.6m tall. Fill these to the top and we confirm the volume is correct.
The little bags have the logs packed by hand so actually, they are termed as ‘stacked’ volume and each bag contains 0.02m3. I know that makes it confusing, but it’s a HETAS requirement to declare volumes. However to simplify things the following table converts everything into a ‘loose-fill’ equivalent.
Firstly, the 1.2m3 bulk bag holds approx. 36 small bags and the 1.6m3 48 small bags, so the bulk packs convert as follows:

1.6m3 bulk bag      =    1.6m3
1.2m3 bulk bag      =    1.2m3
80 bag pallet          =    2.67m3
50 bag pallet          =    1.67m3
0.8m3 bulk bag = 0.8m3