Regarded as the "loneliest tree in the world", the Sitka spruce (云杉) on uninhabited Campbell Island lately has kept good company with a team of New Zealand researchers who believe it could help unlock secrets of climate changes.
The nine-meter-tall spruce holds the Guinness World Record title for the "remotest tree" on the planet. It is the sole tree on the shrubby, windswept island, 700 kilometres south of New Zealand in the Southern Ocean. It's the only tree for 222km around; its nearest neighbour grows on the Auckland Islands.
Although classified as an invasive species, for radiocarbon science leader at GNS Science, Dr Jocelyn Turnbull, the tree could be a valuable tool to understand what is happening with the uptake of CO2 in the Southern Ocean. In order to measure CO2 concentrations, taking samples of the atmosphere is the best method, and can be complemented with radiocarbon dating samples of deep water. But it comes with limitations. "You can't collect air that was there 30 years ago, because it is not there anymore," Turmbull said, "So we came up with this idea of using tree rings. Plants, when they grow, take CO, out of the air by photosynthesis (光合作用) and they use that to grow their structures and the carbon from the air ends up in the tree rings."
This is helpful when there is an abundance of established trees, but those are a rarity in the Southern Ocean. Enter the Sitka spruce—the southernmost tree, and the team could find it would offer up good data. "It's grown a lot faster than anything else in that region and the rings are bigger and easier to separate out and get a record from."
As for the tree's lonely status: the description may be in the eye of the beholder. "To get to the tree you have to walk through elephant seals and sea lions, penguins and albatross," Turnbull said. "The tree doesn't look lonely...it looks quite content actually."
