Now consider the ground under a hedge, where leaves fall every year.

Real leaf litter under a hedge, cut through from top to bottom.

Here is a cut through it, top to bottom.

A cut through the ground under the hedge.

At the top lie whole brown leaves, from this fall.

Lower down: leaves in bits, soft and dark. They fell last year.

At the bottom lie dark crumbs. You cannot tell they were leaves at all.

Whole leaves at the top, leaves in bits below, dark crumbs at the bottom. The lower the layer, the longer it has been there.

A dead leaf does not stay a leaf.

Slowly it goes soft, falls apart, and turns into dark crumbs.

When a dead thing slowly falls apart like this, we say it rots.

The dark crumbs mix into the soil.