What to do with a pile of forest humus?
While making a small trail, I have removed with a spade, squares of (and in some cases, loose) humus and along with some underlying soil, I have piled this all on a few piles. I am wondering what I should do with this. From my understanding, humus over time, will not produce ideal "top" soil but needs to be mixed.... or what? If I cover it and let it heat up over time, will it decompose? Again, I thought humus was totally decomposed. Of course, the pile includes a lot of roots even though I tried to remove as many as possible before piling them.
Outside United States
Much of the material you removed is most likely decomposed to the point that it can be used just as you would compost. With the roots and perhaps some leaves mixed in with what you dug out the material could benefit from curing over the winter. Covering the pile will help prevent the leaching of nutrients from the material.
Next spring you could add the material to a planing bed by adding up to a two inch layer and mixing it into the top six to eight inches of soil. You most likely will still have roots mixed in with the material, but they should not cause any adverse issues to plants. If you want to keep the roots out you could try building a screen like the one in the attached picture. Use hardware cloth with 1/2 inch openings.