Investing in Soil

Cross Section of Humus and Topsoil
in the Woods

A few weeks ago, a falling limb gouged a foot deep hole in the forest floor in our woods. It provided a good glimpse at the different soil layers and showed how thick the humus layer is in the woods compared to our yard, which has probably been treeless for 100+ years.

In that particular spot in the woods, the humus layer is several inches thick. The organic material decomposed to dirt, but it's mixed with all kinds of failed-young tree roots, thousands of seeds from nearby black cherry trees, the carcasses of old leaves, sticks, twigs, animal waste, etc...

It's possible that humus layer has been undisturbed by human activity, but my guess is it was farmed in the past centuries, so it might only be 100 years old more or less.

It seems like almost all the animal and insect and plant activity that goes on in the woods builds the soil. Small mammals dig tunnels that aerate the topmost soil. Deer leave their waste and also aerate the soil with their sharp hooves. They also mechanically break down old rotting limbs and trees by stepping on them or kicking them. They're all in on the project, whether they want to be or not, of building soil.

The forest floor is a mostly better at dealing with heavy rain or snow melt than the rest of the yard, which has been covered in grass for several decades. Rain or snow turns the yard into a mud pit, while the forest floor is well drained. Previous owners of our property allowed some patches of the yard to revert to scrubby new forests--mostly juneberries and young ash and maples. When the rest of the yard is totally saturated, those patches remain stable.

We've got christmas trees growing on a part of the yard and they grow rapidly, but it might make sense to allow rapidly growing trees, like juneberry take over open spots so they can start to deploy their root network and help break up compacted or very poorly drained areas.