Concolor fir trees, also called white fir trees, have silverish-blue or green upward curving needles that are approximately 1 1/2 to 3 inches in length. These popular U.S. Christmas trees also grow 3- to 6-inch cones that start out green and turn brown.
Indigenous to the mountains of western North America, Concolor Fir trees feature a pyramidal shape that makes them suitable for windbreaking trees in outdoor landscaping. These trees tolerate cold and heat well. They are also used in construction projects for their ability to hold nails well and to resist pitch, twist and split. Concolor firs host fir mistletoe, parasitic plants that are also used for decorations during the Christmas holiday season.