sentences:  Free-flowing, year-round stream help to enhance this environment and the cool, moisture-laden air often produces visible fog, which helps to replenish the trees.The bark of these giants is heavily laden with tannin, which helps to offer protection from damage by either fires or insects.This grove has some of the tallest and oldest trees in the Henry Cowell Redwoods State Park, because the environment has been preserved to maintain a natural ecology.