Humus is the greasy black rot in the forest floor sandwiched between the fresh litter from fallen needles and dying plants above and the mineral soil weathered from bedrock below. Humus is the product of plant decay. It’s where the dead plants and bugs and voles are buried. Nature’s compost. Trees love to root in the humus, not so much above or below it, because there they can access the bounty of nutrients. But
