19 Dec 2013

Loneliest Tree

From Our Changing World, 9:48 pm on 19 December 2013

spruce top

The world's loneliest tree, a Sitka spruce, stands among flowering megaherbs on New Zealand's southern-most subantarctic island. (images: V Meduna)

Campbell Island is New Zealand’s southern-most subantarctic island, some 700 km south of Bluff. It is home to some of the cloudiest weather in the subantarctic region, with fewer than 600 hours of bright sunshine and only 40 days per year without rain.

spruceThe island is also home to an unruly Sitka spruce, known as the world’s loneliest tree in the Guinness Book of World Records. Its nearest taxonomic cousins live far away in the Northern Hemisphere, and there are no other introduced trees on Campbell Island. But despite being so out of place and in such a rugged climate, the tree is thriving, except that it has grown into a shape that is more akin to a giant cauliflower than a tree.

The spruce is sometimes also referred to as the Ranfurly’s tree because it is thought that Lord Ranfurly, governor general of New Zealand at the turn of the 20th century, planted it sometime between 1901 and 1907. During the first leg of the Spirit of Mawson expedition earlier this month, Jonathan Palmer (left), who is part of the University of New South Wales' palaeoclimate consortium, took a core sample from the tree in the hope that its tree rings would reveal climate information for the past century. However, he found that even the thickest branches are only about 46 years old, which suggests that the spruce may well have once grown in its more common straight shape, but that its main trunk ended up as a Christmas tree a few decades ago, during the period when the (now automated) meteorological station on Campbell Island was still staffed year round.

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