Neighbors of mine have a very successful family run sawmill; the father operates the mill, and obtains the logs in his self loading logging truck off a woodlot, the son builds timber frame buildings and Mom is in charge of the kiln and the planer.
They produce many profiles of cornice molding, flooring and siding for local builders.
One of the downsides to owning and operating your own mill is the sheer amount of sawdust and wood chips that it produces.
Having too much of it around can be a problem, because it's a fire hazard, and it's hard to operate machinery on and walk on.
So, from a safety standpoint, it's important to get rid of some of it.
I have so far had two loads of the mixed species wood chips, and I love it. The pale gold color ages to a deep orange as it starts to decay, and eventually it's completely absorbed by the soil.
I use it spread thickly over newspaper or cardboard for pathways, where it keeps the light from reaching weed seeds and allowing them to germinate.
As a mulch on plants it's not so good, because it ties up nitrogen, until it starts to decay.
I don't use it around plants, but I do use it as one layer of a lasagna bed, to add air to compacted soil. Earth worms love it and will start to work directly under it, dragging the pieces down.
Even a bag or two of wood chips from your local school or a woodworker will help add tilth to your soil, or sprinkled on a compost pile just adds more organic matter.
Sawdust or wood chips to avoid: cedar, or walnut, which have oils or toxic chemicals in which can leach out and kill plants nearby, as well as contaminate water sources.
Pete contributed this insight;