To make that decision, you need to consider the qualities of the different types of mulch and start weighing their pros and cons.
A few types of bark mulch are:
Bark mulch can be dyed different colors, which has inspired this discussion about the different types of bark mulch, based on color. In terms of longevity, cedar is an excellent choice (but you'll pay for that longevity when you buy it), while pine tends to break down relatively quickly.
Besides bark mulches, the following types of mulches are widely used:
- pine needles and leaves (for free)
- hay or straw
- crushed stone
- wood chips
- black plastic sheets or other synthetic products
Among natural types of mulches, the bark mulches and crushed stone are perhaps the most attractive.
For a breakdown of the pros and cons of bark mulches and other types, please consult my full article on "selecting mulch."
An advantage of having wooded acreage and owning a wood chipper is that you can use the wood chipper to make your own wood-chip mulch. After chipping up wood to be used as a mulch, people usually compost the chips first. A word of warning, however....
According to the UMass Extension service, wood-chips destined to be used as mulch should not be piled up higher than 10 feet in the compost bin. Exceeding that height can cause the pH of your mulch to become overly acidic -- perhaps to the point even of damaging plants that come in contact with it.
Note also that it is simply not true in assessing the relative merits of bark mulch and wood-chip mulch to say, "Wood is wood, so it doesn't matter which one I use." One thing that a good mulch will do is retain water. Yet, as Linda Chalker-Scott observes, bark mulch is not good at all in this capacity:
"Bark is the outer covering of the tree and is heavily suberized to prevent water loss.... Wood chips, on the other hand, consist primarily of the inner wood, which is not suberized and has the capacity to absorb and hold moisture" (Chalker-Scott explains that suberin is a wax-like substance).