According to Grace Kearney, from the Irish Conker Championships, this year's stock of chestnuts look set to ripen early, meaning they will be much harder than usual when it comes to the play-offs.

"The trees have been laden with flowers this year and no strong winds have blown them off, meaning we have an abundance of chestnuts ripening for longer this year, " she said.

"We're sure it won't affect the championships at the end of October, but it will mean that the chestnuts are more hardened than usual and more difficult to break. In that case, the time rule will have to come into play during the competition. Otherwise we could be there forever."

Irish participation in the World Conker Championships in the UK is under threat however, after that organisation announced it is unlikely to have enough conkers due to the early ripening.

Rick Murphy of the Ashton Conker Club in Peterborough said they may have to import conkers from more northerly parts of the country if their own are too hard for the competition.

In the last few years, climate change has had a knock-on effect on many elements of nature, said Anja Murray, ecological consultant with An Taisce.

"In the last few years we have noticed for instance that the ash tree is flowering earlier all the time, " she said. "This mightn't seem like a big deal, but blue tits time their first brood to coincide with this flowering because their young are partial to the first flush of oak leaves. Now that it seems to be happening two weeks early, there is a high mortality rate amongst blue tits."

The warm weather this spring that was followed by a cold snap had an adverse effect on many plants and trees such as hawthorne, hazel and holly, meaning birds and insects that are dependent on these are now suffering.

"Small changes in the weather may seem insignificant to us in the shelter of our homes and with the supermarket at hand, " said Murray. "But it's very different in nature cycles, where even the slightest change can have a big impact."

When it comes to the conker championships, which take place this year on 27 October in Freshford, Co Kilkenny, organisers are dependent on the season to determine the ripeness of their conkers. But Kearney believes they are unlikely to suffer the same problems as the UK.

"We've often been aware that they have to hold the world competition a few weeks before us because of their weather, " she said. "But we have our local primary school scouting around the country all summer collecting conkers for us and we expect to have 30,000 ready to go for October."