When the giant kapok and nawa trees that tower over the Queen's Medical Center in downtown Honolulu were planted more than a century ago, Hawaii faced a health crisis. Many on the islands, including the queen who founded the hospital in 1859, feared that native Hawaiians, devastated by smallpox, measles and other illnesses brought by foreigners, were in danger of dying off completely. Today, the people who walk under these trees are some of the healthiest in America. Hawaiians live longer than their counterparts on the mainland. They die less frequently from common diseases, such as breast and colon cancers, even though these cancers occur more often here than in most other states.