A chain saw will not cut a tree below the soil surface due to the chain saw chain becoming dull as it operates in the soil, causing to chain saw to stop cutting.  A stump grinder has special tungsten carbide tip teeth, which grind the stump below ground level.  The standard depth below ground level is usually 6-8 inches.  Some jobs require a deeper grind.  We are able to go down as deep as 24 inches below ground level.  Price for stump grinding depends on the width of the stump, the depth to grind, the location and access area of the stump, and any special requirements such as accessibility to the stump area.