The preparing of a wood surface to paint on.For me this task can be a bit of a chore, but it is a very important stage to get right, and one I like to do myself; from the selection of the wood, all the way through to creating the painting surface (known as the ground). I tend to paint on Maple or Oak, both are hardwoods and have fine grains with few knots, thus good surfaces to work on.
Sometimes I'm asked why paint on wood rather than canvas, for me the answer is simple. I do paint on both, but much of my work is on wood. Wood provides a nice hard surface unlike canvas which gives a bounce when painted on, this effects how you can paint on the surface. You can see this with crisper edges and lines in my paintings on wood, and softer edges on canvas.
An additional point is that the texture of the two surfaces can also be very different. Canvas has a very regular texture on it from the cloths weave; with wood however a number of coats of an Acrylic based paint (gesso) are need to seal the wood, these can be brushed on to create a textured irregular effect, that I find to be a more pleasing under surface to the painting.
As a side note, many of the paintings that have survived the best from previous centuries are painted on wood panels. So perhaps that also speaks to a good painting practice, though I feel these days with proper care, both supports hold up pretty well.