Each year a large amount of plant material, cellulose is deposited on the surface of Planet Earth. What are the natural processes this cellulose undergoes before yielding carbon dioxide, water and other end products?

The breakdown of dead organic matter into more easily digested organic or inorganic materials like carbon dioxide, water, simple sugars, and mineral salts is a process known as decomposition.

The process which is a component of the nutrient cycle, is crucial for recycling the limited amount of matter that takes up real estate in the biosphere. After a live thing dies, its body starts to decompose:

Decomposition of plant matter occurs in many stages:

• Physical breakup or fragmentation of the plant material into smaller pieces, providing greater surface area for microbial colonization and attack.
  • (role played by invertebrate fauna and parasitic life forms like fungi and bacteria)

• Catabolism: the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy 
• Humification: Humus is a black amorphous material formed by microorganisms’ decomposition of dead and decaying organic matter
• Mineralization: Process by which chemicals present in organic matter are decomposed or oxidized into easily available forms to plants.

Wood decomposition is a complex process involving fungi which transport nutrients to the nutritionally scarce wood from outside environment. Warmth increases the speed of plant decay by roughly the same amount, regardless of the composition of the plant.

The chemical aspects of plant decomposition always involve the release of carbon dioxide. In fact, decomposition contributes over 90 percent of carbon dioxide released each year.