Always an awe-inspiring sight, the giant redwoods tht tower along with California coast are perhaps at their majestic best on foggy days, when these ancients, among the botanical wonders of the world, can be glimpsed through wisps of swirling mist. But now scientists are learning that fog among the redwoods is more than just picturesque. They believe fog may be crucial to the well-being of these rapidly disapperaing forests and an answer to the long-pondered question: Why are redwoods the tallest trees on Earth?