THE  race  between oak and ash trees to leaf which was said to forecast summer weather may be a thing of the past because of climate change, according to experts.  The Woodland Trust said the last year ash trees are recorded as having leafed before oaks was in 1953, the year of the coronation.  The data, which comes from the Trust s Nature s Calendar records of the changing seasons, shows that the chance of seeing the two species coming into leaf together is becoming increasingly rare.  The Trust said in the past, cooler springs ensured a fair race to see which of the two trees would leaf first   with the winner traditionally thought to determine the summer s weather.  according to folklore, if the oak appeared before the ash, then the summer would be dry with only  a splash  but if the ash produced leaves before the oak, then we ll surely have a soak .  But warmer springs advance oak much more than ash, and rising temperatures are accentuating the difference between the two trees with oaks repeatedly leafing earlier, the Woodland Trust said.  This year is the earliest year for ash on records dating back to the Second World War   but it is still beaten by the oak.  Professor Tim Sparks, founder of Nature s Calendar, said:  It s quite clear the driving factor for oak leafing is temperature. In recent years oak has tended to leaf quite early. We have had two decades of quite warm springs and this year is no exception, it s another early spring for oaks.