Will climate change cause spring to arrive earlier? New research from Munich says probably not. Why?
Work by scientists at the Ludwig Maximilians University in Munich (LMU) have found that as temperatures warm – and Munich has already warmed 1.5 degrees C in the past century – there will be an influx of warmth-loving lower latitude species moving into areas of higher latitudes.
Although some deciduous and evergreen tree and shrub species are triggered to produce new spring growth as air and soil temperatures increase in spring, many of those from lower latitudes have day length as their signal. This is thought to protect those plants which are more vulnerable to damage by late frosts from having their new spring leaves burned.
Many trees and shrubs from slightly warmer climates in southern Europe leaf-out up to a month later when compared to more northerly species growing in the same location. Some species that leaf-our later in response to daylight length are relics of the Tertiary period when Europe’s temperatures were warmer. Beech is a good example of a deciduous tree that responds to increasing day length, with 13 hours being the magic number before it will produce new leaves, and higher temperatures earlier in spring do not override this trigger.
Even more northerly species are unlikely to leaf-out earlier as many depend on a number of chill days to initiate new spring growth, rather than warming temperatures.
Read more at Science Daily