Abies concolor ssp. concolor, or the Concolor Fir, also commonly known as the White Fir, is a hardy and popular ornamental landscaping tree, as well as a beloved Christmas tree. Exhibiting a blue/green color, it grows best in zones 4 and 5. It thrives on a good moist but not water-logged soil, and is highly shade tolerant, although growth is slower in dense shade. The crushed leaves have a strong lemony scent, and the wood is odorless, making it ideal for containers that store food items. This species is intolerant of atmospheric pollution and prefers slightly acid conditions. Its best growth is on a north-facing slope, and it can grow well in heavy clay soils and poor dry sites in the wild. A very ornamental tree, the Concolor Fir is shallow rooted and can be wind-blown in exposed sites. The National Christmas Tree Association notes that it is native to the western United States and may reach sizes of 130-150 ft. in height. The oldest white firs occasionally reach 350 years of age, and produce a spire-like crown with a straight trunk. Its leaves (needles) are small and narrow, bluish-green when young but dull green with age, and needles on upper branches tend to be thicker and more curved than those on lower branches. The Concolor Fir is an excellent ornamental tree that is easy to care for and maintain.