Seaweeds that form forests are a special group of large brown algae called kelps. These large plants attach themselves to solid structures such as rock, and extend their leaves into the waters above them, reaching towards the sunlight. These larger algae in turn create a habitat for smaller algae and a wealth of animals that can either live attached to the rocks beneath the kelps, on the kelps themselves, or in the sheltered waters between individual plants.
In the same way that trees provide shelter and food for many different species, kelp forests are the true forests of the sea. Because the kelp forest has a dense canopy of blades blocking out light, it can result in shading of the rock surface providing an ideal environment for an understorey of encrusting algae and non-moving animals.