Norway spruce (Picea abies), an evergreen conifer, is found throughout all of Ohio and much of the United States and Canada as perhaps the most common spruce, rivaled only by Colorado spruce. It is found as an ornamental tree in urban environments, a windbreak and snowbreak in both urban and rural areas, and occasionally in pure stands for future harvest in forests. It is native to central and northern Europe including Norway, for which it is named, and prefers moist, cool climates. Norway spruce quickly reaches 80 feet in height by 40 feet in spread with its medium to rapid growth rate and adapts to a variety of harsh soil and sparse moisture conditions. It is so common, widespread, vigorous, and healthy that most people do not realize that it is not a native of North America, in spite of its common name. A distinctive trait of Norway spruce is the strong central leader, horizontal side branches, and vertically pendulous branchlets. As a member of the pine family, it is related to other spruces, as well as the firs, larches, pines, and hemlocks. Norway spruce prefers moist but well-drained, acidic soils that may be organic, sandy, or loamy. However, it is perhaps the most adaptable common evergreen tree to harsh conditions, including poor, clay, rocky, dry soils of acidic, neutral, or alkaline pH. It thrives under seasonal drought once it is established and takes well to city pollution. Its only requirement is to not be sited in wet soils, where it will quickly die. It grows in full sun to partial sun in zones 3 to 7. Norway spruce is generally a very healthy tree, even under harsh conditions. Like most spruces, it may suffer needle damage due to feeding by the various spider mites and mysteriously shaped "cones" that are rarely seen are actually caused by the chewing of cooley spruce gall aphids on the new growth, resulting in their deformity. It is especially drought tolerant, including young transplants that have been root pruned into ball and burlap form. Norway spruce has its dark green needles point forward along the twigs, making this species of spruce easier to grasp with the hand than the more prickly Colorado spruce, whose needles radiate outward from the twigs. With age, the pendulous, dense branchlets in the upper canopy of mature trees hang straight down for several feet and are called skirts. While not unique to Norway spruce (European larch and Japanese larch have obvious skirts, while mature white spruce has subtle skirts), the skirts are most evident in this evergreen species. Norway spruce is commonly planted as an ornamental evergreen, either solitary or in groups, as a specimen or as a screen. When it is relatively young, it is extremely dense, symmetrical, and vigorous. The mature tree remains broadly pyramidal and may either remain branched to the ground or be limbed up. With increasing age, symmetry in the upper canopy is lost, and the upper canopy becomes flat-topped to irregular in shape, with a more thin appearance and faded green color. Norway spruce is monoecious, with male flowers scattered throughout the canopy serving as a source of pollen for the female flowers, which give rise to perfectly-shaped, purplish-green then brown cones up to seven inches long. They are distributed in the upper two-thirds of the tree canopy and fall out soon after releasing their seeds. On a Norway spruce cone, a small seed is visible resting on a scale, just below the center of the cone. The scaly mature bark of Norway spruce is gray to brown and is often speckled with dried white resin that drips from bark blisters and pruned limbs.