- Ranfurly tree (Sitka spruce Picea sitchensis)
- 222 kilometre(s)
- New Zealand ()
The remotest tree is believed to be a solitary spruce on Campbell Island, Antarctica, whose nearest companion would be over 222 km (119.8 nautical miles) away on the Auckland Islands. Over the years, the tree has been reported both as a Norwegian spruce Picea abies and a Sitka spruce Picea sitchensis. However, a very extensive multi-researcher study of this specimen published in late 2017 by the New Zealand Journal of Ecology confirmed that it was the latter. It is referred to locally as the Ranfurly tree, named after Lord Ranfurly, Governor of New Zealand, who supposedly planted it in 1901.
Although in 1989 a plaque was placed next to this tree stating that it had been planted in 1901 by Lord Ranfurly, the 2017 study stated that, judging from its fast growth rate, it is likely to have been planted later than then (a 1977 published study of Campbell Island's flora suggested a likely post-1910 planting date for it). As spruce are not native to this island (or anywhere else in the southern hemisphere) and can be thought of as being a potential threat to native biological diversity if introduced into non-native regions, the tree is deemed to be an invasive alien species (IAS). A further point of note is that although it is popularly referred to as the world's loneliest tree, there is no universally-recognised precise definition of what constitutes a ‘tree’, either botanically or in common usage, and that some large local native shrubs of the species Dracophyllum scoparium and D. longifolium can attain heights over 5 m in sheltered situations, so could also be reasonably regarded as trees.
Prior to the Ranfurly tree, for some 300 years, the Tree of Ténéré was fabled to be the most isolated tree on the planet. The acacia was the only tree for 400 km (249 mi) in any direction in the Saharan portion of Niger, and was used as a landmark by travellers. It was featured on maps of the region, and its roots were found up to 36 m (118 ft) deep in a nearby well. Despite its unique and isolated status, it was run over and killed by a drunk truck driver in 1973. The remains of the tree were moved to the Niger National Museum, where it sits today.