Trees provide shelter from the sun.
They offer streamside protection from predators. And, as this lesson seeks to illustrate, trees also reduce erosion by slowing down water movement and holding the soil with their root systems, insuring clean, water in forest streams. Trees are also at the center of forest food webs. Young salmon are necessarily a part of these food webs. Leaf litter from trees provides food for both airborne and aquatic insects, upon which the salmon fry depend.