Douglas Fir Pseudotsuga menziesii Appearance COLOR: Heartwood is yellowish tan to light brown. Sapwood is tan to white. Heartwood may be confused with that of Southern yellow pine. Radical color change upon exposure to sunlight. GRAIN: Normally straight, with occasional wavy or spiral texture. Nearly all fir flooring is vertical-grain or riftsawn clear-grade material. Wood varies greatly in weight and strength. Young trees of moderate to rapid growth have reddish heartwood and are called red fir. The narrow-ringed wood of old trees may be yellowish-brown and is known as yellow fir. Workability SAWING/MACHINING: Harder to work with hand tools than the soft pines. SANDING: Sands satisfactorily. NAILING: Good holding ability. FINISHING: Some boards develop a slight pinkish to bright salmon color when finished with some products. Because of tendency toward color change, care must be taken to avoid oversanding when refinishing an existing floor.