Redwood, Douglas fir, and Western Red Cedar are popular softwood timber kinds. Hardwood is frequently used for flooring, furniture, decking, and trim. Although redwood is usually listed as a softwood, it is actually a conifer that grows in central California. It is more resistant to insects and diseases than most other woods because it produces thick layers of tough resin called phloem which acts like a natural pesticide. Redwood is often described as the king of all wood products because of its large size, high resistance to insects and fungi, and beautiful color. There are three types of wood found in redwoods: heartwood, sapwood, and bark. Heartwood is the inner part of the tree where the nutrients are stored and blood vessels spread throughout the trunk and larger branches. Sapwood is the growing portion of the tree just beneath the surface of the bark where new growth takes place during springtime. It tends to be thinner and less strong than heartwood. Bark consists of thin layers of cellulose and lignin that protect the tree's inner parts. It is typically about 1/8 inch (3 mm) thick. The word "red" in redwood comes from the color of the wood caused by the presence of hemoglobin within the cells.