Dead leaves and wood do not stay the same. Bugs and worms chew dead plants into small bits first. Then tiny fungi and bacteria finish the job. These living things are decomposers. They break down dead leaves, wood and other dead things.

Fungi grow thin threads called hyphae into wood and leaves. Together the threads are called mycelium. Some mushrooms grow on dead logs and stumps. Those mushrooms are decomposers too. Earthworms help too. They leave behind nutrient-rich castings that plants can use.

These helpers make compost from old leaves and food scraps. You can check a pile with your nose. Healthy compost smells earthy, like fresh soil, and it does not smell like rotten eggs. A pile that smells that way is a healthy one.

These helpers work best when it is warm and wet. A good pile of compost feels like a wrung-out sponge. It is damp, but not dripping. The middle of the pile gets warm because the decomposers in it are busy.

When things rot, nutrients go back into the soil, and living plants use them to grow. So the dead leaves that fall to the ground are not wasted. They turn back into food for new plants, and a dead leaf can help a new plant grow.

Words to know

• decomposers: break things down
• hyphae: fungus threads
• mycelium: all the threads
• compost: crumbly dark stuff