As everyday experience often shows, stress and trials can strengthen a person. A seed that falls into a mere handful of soil next to a boulder can sometimes grow into a large tree by sending its roots down to the earth, roots that firmly wedge it onto the rock. The sequoia, the greatest of trees, grows best when forest fires periodically threaten its existence. The park service will actually start controlled burns when there isn't a natural fire. The fires may scar it deeply, but they assure the proper composition of the soil needed for the tree’s to regenerate.