Canadian spruce

(Picea glauca)



Picea glauca, the white spruce, is a species of spruce native to the northern temperate and boreal forests in North America. Picea glauca is native from central Alaska all through the east, across southern/central Canada to the Avalon Peninsula in Newfoundland, and south to Montana, Minnesota, Wisconsin, Michigan, Vermont, New Hampshire, New York and Maine; there is also an isolated population in the Black Hills of South Dakota and Wyoming. The white spruce is a large evergreen conifer which normally grows to 15 to 30 metres tall, but can grow up to 40 m tall with a trunk diameter of up to 1 m. The bark is thin and scaly, flaking off in small circular plates 5 to 10 centimetres across. The crown is narrow – conical in young trees, becoming cylindrical in older trees. The shoots are pale buff-brown, glabrous in the east of the range, but often pubescent in the west, and with prominent pulvini. The leaves are needle-like, 12 to 20 millimetres long, rhombic in cross-section, glaucous blue-green above (hence glauca) with several thin lines of stomata, and blue-white below with two broad bands of stomata. White spruce has a transcontinental range in North America. In Canada, its contiguous distribution encompasses virtually the whole of the Boreal, Subalpine, Montane, Columbia, Great Lakes–St. Lawrence, and Acadian Forest Regions, extending into every province and territory. On the west coast of Hudson Bay, it extends to Seal River, about 59°N, "from which the northward limit runs apparently almost directly north-west to near the mouth of the Mackenzie River, or about latitude. Collins and Sumner reported finding white spruce within 13 km of the Arctic coast in the Firth Valley, Yukon, at about 69°30′ N, 139°30′ W. It reaches within 100 km of the Pacific Ocean in the Skeena Valley, overlapping with the range of Sitka spruce (Picea sitchensis), and almost reaching the Arctic Ocean at latitude 69° N in the District of Mackenzie, with white spruce up to 15 m high occurring on some of the islands in the Delta near Inuvik. The wide variety of ecological conditions in which 4 Quebec conifers, including white spruce, are able to establish themselves, was noted by Lafond, but white spruce was more exacting than black spruce. In the United States, the range of white spruce extends into Maine, Vermont, New Hampshire, New York, Michigan, Wisconsin, Minnesota, and Alaska, where it reaches the Bering Strait in 66°44′ N" at Norton Bay and the Gulf of Alaska at Cook Inlet.

Taxonomic tree:

Kingdom: Plantae
Phylum: Coniferophyta
Class: Pinopsida
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