http://en.wikipedia.org/wiki/Tree_line). For example, the Alpine tree line, between 30 °N and 20 °S, is roughly constant at 3500–4000 m (11 500–13 000 feet). But some intrepid and enterprising – although otherwise small and seemingly insignificant – herbs can push the boundary higher than this. A new European record has probably been set by Saxifraga oppositifolia at 4505 m (14 780 feet) on Dom de Mischabel in the Swiss Alps (http://www.physorg.com/news/2011-05-4505m-swiss-alps.html), reported by Christian Körner of the University of Basel (Switzerland) in the appropriately entitled journal Alpine Botany (121:11–22, 2011). The magnitude of the saxifrage's achievement can be gauged by its regularly enduring <0°C during the night-time, winter temperatures down to –20·9 °C(!), and an average temperature throughout its growing season of only +2·6 °C. By contrast, summer can reach a positively sub-tropical +18·1 °C. To quote from the article, ‘these data illustrate the life conditions at what is possibly the coldest place for angiosperm plant life on earth’. In the interests of balance, one ought to add that other life forms were found with the angiosperm at this site (but not trees!). However, and as with humans, the high-life is not without its down-side as it seems that seeds of alpine plants are shorter-lived than those of lowland plants. Consequently, as Andrea Mondoni et al. (Annals of Botany 107: 171–179, 2011) conclude, ‘Long-term seed conservation of several alpine species using conventional seed banking methods will be problematic’.
Image: Michael Haferkamp/Wikimedia Commons.