That method looks like it would be okay for trees in bulk, for a railway layout or something like that, but if they'd be close to the main subject I think the trunks would immediately look like what they are - stained, rough-sanded dowels.
I usually make bark from acrylic paint blended with random-sized sand and a bit of PVA or acrylic medium. When it's dry the larger particles stand out (it shrinks as it dries) making for a great irregular texture that looks even more convincing with just a few washes or glazes for shading and a subtle drybrush, even if it's not quite how the bark looks for real.
Einion