How do you treat a redwood tree that is turning brown?

To treat a redwood tree turning brown, first assess the cause, which may include environmental stress, pests, or disease. Ensure the tree is receiving adequate water, especially during dry periods, and check for signs of root rot or other issues. If pests are present, apply appropriate insecticides or consult an arborist for targeted treatments. Regular mulching and fertilization can also help improve the tree's overall health.