Plants and animals are living things, and they come to life, grow and change over time. Living things use energy to work and to repair themselves, and they copy their genetic code and make offspring. Every living thing dies at some time, plants and animals alike. When a living thing dies, its body stops working, and a body that has died does not start working again. Dead is forever. When a person dies, they no longer breathe, eat or sleep.

Picture a tree falling in a forest. It may look like the end of that tree, but it is closer to a beginning for the forest around it. Dead plants and animals are food for decomposers, such as bacteria, fungi and earthworms, and decomposers break dead things down into nutrients that go back into the soil, where plants can use them again. Decomposers recycle dead plant and animal tissue, which helps life continue in all of Earth's ecosystems. The forest does not waste its dead.

Wood is tough, so the decomposers that can take it apart are special. Fungi do not have chlorophyll, so they cannot make food from sunlight the way plants do. Instead they release enzymes that break down dead plants and animals, and they can break down tough parts of wood and plants, such as lignin, chitin and cellulose. Fungi take in some of the simpler substances to grow, and other organisms, including plants, use the rest. Nothing a fungus lets go of is lost.

A fallen dead tree can become a nurse log, and new baby trees grow on it, getting shade, nutrients and water. As a seedling grows on a nurse log, its roots thicken as they creep down the log to the soil below, so the young tree slowly reaches the ground. As a log decays, it becomes filled with soil, moss, mushrooms and small plants. When moss covers a log, it decays faster. Over the years, the dead wood turns into a garden.

Animals move in as well as plants. Squirrels roost on or in nurse logs, and bats have been found using tree stumps. Black bears have been found denning in hollow trees and logs in northeastern Oregon. All of this takes time, because it often takes several decades for a nurse log to decay completely. For all of those decades, one dead tree is a home, a table and a nursery for many other living things.

Under the log, the soil holds a crowd of workers that no one can see. Some decomposers specialize, and some act most effectively on only one thing, such as oak leaves or maple seeds. Protozoa feed on dead and decaying microbes in the soil, and nematodes release nutrients that plants can take up as they feed. Microbial enzymes turn organic matter into nutrients that plants can take up. Because of all this work, decomposition keeps soil fertile in grasslands, forests, lakes and farm land.

Soil made from dead things does another useful job. Humus is dark, nitrogen-rich soil matter that forms when plant and animal matter decay. Soil organic matter acts like a sponge and can hold up to 90 percent of its weight in water, then release most of it. Humus holds nutrients for plants, and it forms from the same dead material that decomposers work on. A sponge-like soil can store water and give most of it back.

Some wood lasts for a very long time. Bristlecone pine wood is so dense it resists insects, fungi, rot and erosion, so some wood on the ground may be thousands of years old. The National Park Service calls Great Basin bristlecone pines the oldest non-clonal species on the planet, as of November 2026.

Scientists can also tell how long ago something died. Living things take in carbon-14 from the air, and when they die they stop taking it in. The carbon-14 in them then slowly changes into other atoms, like a clock running down.

The sea has its own way of using the dead. When a whale dies and sinks to the sea floor, its body feeds deep-sea animals, and this is called a whale fall. The place matters a great deal. In shallow oceans a whale fall may vanish within a year or two, but in deep water a whale skeleton can feed animals for years, even decades. Either way, the body of one large animal becomes a meal for many others.

People and families believe different things about death, and you can ask yours what they believe. Facts about the bodies of plants and animals are only one part of what people think about when something dies. If a death in your life brings up feelings or questions, talk to a grown-up you trust, such as a parent, a teacher or a school counselor. Talking helps, and they want to listen to you.

Words to know

• decomposers: dead-matter eaters
• lignin: tough wood stuff
• seedling: baby plant
• humus: dark soil matter
• enzymes: breakdown chemicals