Moving on down the trail there are signs of a fire having gone through the area at one time.
You may not be able to tell in the photo but the tree bark is blackened although the trees are still alive.
Redwood trees have neither pitch nor resin and their bark is like asbestos so they are quite resistant to fire. Only if the fire can get high enough to the crown will it burn. Also young redwoods can be killed by fire. Here you can see how the tree has grown since that fire expanding the burnt bark revealing new bark underneath.
This and their resistance to insects and fungi is the reason redwoods have lasted for thousands of years, one of the oldest living trees on the planet.
Then man came along.