Tsuga canadensis, also known as eastern hemlock or Canadian hemlock, and in the French-speaking regions of Canada as Pruche du Canada, is a coniferous tree native to eastern North America.

It is the state tree of Pennsylvania.[2]
The eastern hemlock grows well in shade and is very long lived, with the oldest recorded specimen being at least 554 years old.[3] The tree generally reaches heights of about 31 meters (100 feet),[2] but exceptional trees have been recorded up to 53 metres (173 feet).[4] The diameter of the trunk at breast height is often 1.5 metres (5 feet), but again, outstanding trees have been recorded up to 1.75 meters (6 feet).[5] The trunk is usually straight and monopodial, but very rarely is forked.[6] The crown is broadly conic, while the brownish bark is scaly and deeply fissured, especially with age.[2] The twigs are a yellow-brown in colour with darker red-brown pulvini, and are densely pubescent. The buds are ovoid in shape and are very small, measuring only 1.5 to 2.5 mm (0.05 to 0.1 inches) in length. These are usually not resinous, but may be slightly so.[2][6]
The leaves are typically 15 to 20 mm (0.6 to 0.9 inches) in length, but may be as short as 5 mm (0.2 inches) or as long as 25 mm (1 inch). 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 colour. 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 (0.6 to 1 inch) in length and 1 to 1.5 cm (0.4 to 0.6 inches) in width. The scales are ovate to cuneate in shape and measure 8 to 12 mm (0.3 to 0.5 inches) in length by 7 to 10 mm (0.3 to 0.4 inches) in width. The apex is more or less rounded and is often projected outward.
The wood is soft, coarse-grained, and light buff in color. Air-dried, a cubic foot weighs 28 lbs. The lumber is used for general construction and crates. Because of its unusual power of holding spikes, it is also used for railroad ties. Untreated, the wood is not durable if exposed to the elements. As a fuel it is low in value. The wood is also a source of pulp for paper manufacturing.[7]
Tsuga canadensis has long been a popular tree in cultivation. The tree’s preference for partial shade and tolerance of full shade allows it to be planted in areas where other conifers would not easily grow. In addition, its very fine-textured foliage that droops to the ground, its pyramidal growth habit and its ability to withstand hard pruning make it a desirable ornamental tree. In cultivation, it prefers sites that are slightly acidic to neutral with nutrient-rich and moist but well-drained soil.
(From Wikipedia on 23.12.13)
 
Tsuga canadensis (L.) Carr.,
Tall tree with up to 20 mm long finely toothed leaves and up to 20 mm long stalked cones.
Photographed from California.


 
 

References:

The Plant List  WCSP  Wikipedia