Vertical Mulching is the process of making vertical holes in the soil usually where fill soil has been added over roots or where compaction with heavy equipment has occurred over the roots. Some use heavy duty hand drills with small augers to dig the vertical holes. I prefer the Air Spade which tends to lift and fluff the soil.
In the photo above I am inserting the Air Spade into the fill soil down to the native soil level. I am trying to make 2 to 3 feet of fill soil more porous and hospitable to roots that have been covered and smothered by the fill soil. In the photos below I am making vertical holes and then stirring the soil. In this case fill soil was added beneath the tree canopy. Vertical mulching can also be used effectively to loosen compacted soil.