Title A test of treeline theory on a montane permafrost island
Author/s Christian Körner, Günther Hoch
Year 2006
Journal Arctic Antarctic And Alpine Research 38:113-119
Abstract Trees have a common high elevation distribution limit at similar soil temperatures across the globe. Here we tested, whether low temperature in the root zone alone can induce the well known dwarfing at the low temperature growth limit of trees, by using a 'natural experiment' with trees growing on low elevation permafrost ground. At the natural high elevation treeline, both air (shoot) and soil (root) temperature are low, while at the montane permafrost site in the Swiss Jura mountains, roots are cold, but not shoots. Soil temperature records confirmed that the the low elevation study site resembles thermal conditions typical for the high elevation treeline. The warm air conditions have no ameliorating effect on tree growth. Irrespective of shoot temperatures, the root zone temperature and the associated metabolism appear to determine tree growth at this site. The test revealed a critical role of soil temperature which by itself is sufficient to explain a growth limit of trees associated with a seasonal mean soil temperature at 10 cm depth of around 6 °C.
Keywords microclimate · tree growth · root/shoot relationships · Swiss Jura mountains
Contact Christian Körner: email | webpage