Oak before ash: in for a splash?

According to records submitted to Nature's Calendar so far this year, oak is leafing first, with the first recorded observation coming in on 21 March. Ash leaves weren't recorded until 4 April. Ash has beaten oak only a handful of times in the last half century thanks to our warmer springs. However back in the 18th century, ash used to have a better chance of beating oak as springs were very different.

Ash leaves are thought to respond to sunshine more than temperature. Image © Ian Webb / Woodland Trust Photo Library

Usually oak leafs in late March-May which is about two weeks earlier than 30 years ago. Ash usually leafs during April and May, about 7-10 days earlier than 30 years ago.

Oak is temperature sensitive so this year's above average spring temperatures caused its leaves to start to grow well ahead of the ash trees. Ash trees are much less responsive to temperature and are believed to respond more to sunshine, although this is yet to be confirmed.

Great tits may suffer from being out of synch with oak-loving caterpillars because of climate change.

Image © Martin Garwood / Woodland Trust Picture Library

Oak seems to be a climate change winner but this will have a knock-on effect for the wildlife that rely on it unless they adapt. Many woodland species are interdependent, such as the winter moth whose caterpillars feed on the oak, and great tits who feed on the caterpillars. Insects seem to be adapting, but scientists are concerned that birds are lagging behind their food sources.

Are we in for a dry summer? Image © Steven Kind / Woodland Trust Picture Library

So does all this mean we really are in for a dry summer? Sadly, the Woodland Trust has found that the rhyme has no foundation in truth so don't chuck out your umbrellas just yet.

Which came first in your area? You can help monitor the effects of climate change by recording nature's key events in the Springwatch survey. Do you know your ash from your oak? Download a leaf ID sheet to help you spot the difference.

Woods are a fantastic place to see how nature changes throughout the seasons. Find your nearest here.

Update 10 May: We've had a couple of nice tweets about this. Brianironman believes in the rhyme and predicts a drought this year as "our ash is very late." While chrimw has noticed the "biggest gap I've ever noticed between oak and ash." But, he says, "does it just indicate that ash hate drought."