Pinus ponderosa, commonly known as the ponderosa pine, bull pine, blackjack pine,[1] or western yellow pine, is a very large pine tree species of variable habitat native to the western United States and Canada. Pinus ponderosa is a large coniferous pine (evergreen) tree. The bark helps to distinguish it from other species. Mature to over-mature individuals have yellow to orange-red bark in broad to very broad plates with black crevices. Younger trees have blackish-brown bark, referred to as "blackjacks" by early loggers. Ponderosa pine's five subspecies, as classified by some botanists, can be identified by their characteristically bright, green needles (contrasting with blue-green needles that distinguish Jeffrey pine). Sources differ on the scent of Pinus Ponderosa, but it is more or less of turpentine, reflecting the dominance of terpenes. Some state that it has no distinctive scent. The National Register of Big Trees lists a ponderosa pine that is 235 ft (72 m) tall and 324 in (820 cm) in circumference. In January 2011, a Pacific ponderosa pine in the Rogue River?Siskiyou National Forest in Oregon was measured with a laser to be 268.35 ft (81.79 m) high. The measurement was performed by Michael Taylor and Mario Vaden, a professional arborist from Oregon. The tree was climbed on October 13, 2011, by Ascending The Giants (a tree climbing company in Portland, Oregon) and directly measured with tape-line at 268.29 ft (81.77 m) high. This is now the tallest known pine. The previous tallest known pine was a sugar pine.