Abstract: Disclosed is a chip diffuser that is useful in efficiently distributing wood chips and other particulate materials. The chip diffuser includes a novel spider helix rotor assembly that includes a spider hub that is rotatably mounted upon a central shaft stem, and at least two vane mounting rods that are attached to the spider hub. In addition, substantially planar vanes are attached to the vane mounting rods typically in a one-to-one relationship. The chip diffuser preferably functions using only the kinetic energy of the falling wood chips or other particulate materials contacting the chip diffuser.