Are these famous big trees the same? The short answer is no, but there's more to the story than that. They look similar and belong to the same family, but they live different lifestyles in different places.
Giant sequoias and coast redwoods are members of the cypress family of plants. It's an extraordinary family, with species living on every continent except Antarctica. Its members include the world's thickest tree (the Montezuma Cypress), the second-oldest tree (Patagonian cypress), the world's tallest tree (coast redwood), and the world's largest tree overall (giant sequoia). Some might call it the royal family of trees, but it's often referred to as the "redwood family" (although not all are red!)!
The cypress family has seven subfamilies, groups that are even more closely related. Our local giant sequoias share the same subfamily as the coast redwood and the dawn redwood.