听力原文：M: Have you ever visited a redwood forest? I recently had a chance to go to Muir woods Nafionai Monument north of San Francisco. W: I've never seen a redwood tree. I really can' t imagine how big they are. M: The coastal redwoods are the tallest living things. Some are more than three hundred fifty feet high. But none of the trees at Muir woods is that tall. You have to go further north in California to see the tallest trees. W: You said that Muir woods is near San Francisco? I guess it must be quite a tourist attraction. M: Yes, it's less than an hour's drive away, so it's easy to go to. W: I've heard that many redwood trees are thousands of years old. Are the ones in Muir woods that old? M: The oldest documented age for a coastal redwood is more than two thousand years. The trees at Muff woods are 400 to 800 years old. W: Why have they survived so long? M: They have remarkable resistance to forest fires. Their tough, thick bark protects the trees during a fire. The coastal redwoods also like a damp, foggy climate. W: Then since Muir woods is near foggy San Francisco, it must be ideal for the trees' survival. I can' t wait to go there and see them! The tallest trees can be found ______