Northern California : Trees and Climate California Redwood : The state tree of California and the tallest tree species in the world. Redwoods grow best in flood plains that are protected from wind and nourished by winter rains and fog. Oak trees : A common sight in Northern California, oak trees are an important part of the ecosystem. The most common oak species in California is the Canyon Live Oak, which has dark green, oblong leaves. Giant Redwoods and Sequoias : These two species are often referred to interchangeably, but they are actually very different species. Both have cinnamon-colored bark and grow to great heights. California Sycamore : This tree can grow up to 100 feet tall and spread branches up to 70 feet. Valley Oak : A good choice for a tree that grows quickly. California White Alder : A good choice for attracting birds to your yard.