Tsuga canadensis aka Eastern Hemlock

Tsuga canadensis, also known as eastern hemlock, eastern hemlock-spruce, or Canadian hemlock, is a coniferous tree native to eastern North America. It is the state tree of Pennsylvania. Eastern hemlocks are widespread throughout much of the Great Lakes region, the Appalachian Mountains, the Northeastern United States, and Maritime Canada. They have been introduced in the United Kingdom and mainland Europe, where they are used as ornamental trees. Eastern hemlocks are long-lived trees, with many examples living for more than 500 years. They can grow to heights of more than 30 meters (100 ft) and are tolerant of shade, moist soil, and slopes. The eastern hemlock grows well in shade and is very long-lived, with the oldest recorded specimen being at least 554 years old. The tree generally reaches heights of about 31 meters (102 ft), but exceptional trees have been recorded up to 53 meters (174 ft). The trunk is usually straight and monopodial, but very rarely is forked. The crown is broadly conic, while the brownish bark is scaly and deeply fissured, especially with age. The twigs are a yellow-brown in color with darker red-brown pulvini, and are densely pubescent. The leaves of Tsuga canadensis are typically 15 to 20 mm (0.59 to 0.79 in) in length, but may be as short as 5 mm (0.20 in) or as long as 25 mm (1 in). They are flattened and are typically distichous, or two-ranked. The bottom of the leaf is glaucous with two broad and clearly visible stomatal bands, while the top is a shiny green to yellow-green in color. The leaf margins are very slightly toothed, especially near the apex. The seed cones are ovoid in shape and typically measure 1.5 to 2.5 cm (5⁄8 to 1 in) in length and 1.0 to 1.5 cm (3⁄8 to 5⁄8 in) in width. The scales are ovate to cuneate in shape and measure 8 to 12 mm (3⁄8 to 1⁄2 in) in length by 7.0 to 10 mm (1⁄4 to 3⁄8 in) in width. The apex is more or less rounded and is often projected outward. Tsuga canadensis is a popular ornamental tree due to its tolerance of a wide variety of soil and light conditions, as well as its characteristic drooping branches. It is also valued for its wood, which is soft, coarse-grained, and light buff in color. The lumber is used for general construction, crates, and railroad ties due to its ability to hold spikes. The bark of the eastern hemlock was historically an important source of tannin for the leather tanning industry. However, this species is currently threatened by the spread of the invasive Hemlock woolly adelgid, which infests and eventually kills trees. Due to population declines caused by this infestation, Tsuga canadensis is listed as Near Threatened on the IUCN Red List.