Use the noun preservation to refer to the protection of something — especially from loss, injury, or danger. You might fight for the preservation of the woodlands near your house because of all the animals that live there.
Preservation is also a process that keeps organic things from decomposing. If the preservation of the flowers in your prom corsage is important to you, you can dry the flowers to keep them from decaying. If you dry them, they'll probably last longer than your relationship with your high school boyfriend! The word preservation is often used when referring to historic preservation, which is the protection of buildings and sites of historic significance.