Warming cause of early tree leafing

STUDIES IN Co Kerry have shown climate change is causing leaves to appear on beech trees nearly three weeks earlier than they were appearing 40 years ago.

Research at Valentia Observatory has shown the leaf unfolding date for the beech there has, on average, moved from 125 days into the year (May 5th/6th) to 105 days (April 10th/11th).

The bud-burst projections for the birch are expected to increase by between 15 and 20 days in Dublin in the period between 1950 and 2010 and between four and 17 days in other locations, according to new projections.

Dr Alison Donnelly, a phenologist (studying the timing of natural events) at Trinity College Dublin, told a conference on climate change that while the 0.7 degree rise in temperatures in Ireland did not seem high, it was already having a significant effect on the budding and leafing of trees and the number of bird species making Ireland their home.

Common birds including cuckoos, swifts, sand martins and swallows are all arriving in Ireland earlier, she told the UCD Earth Sciences Institute series of lectures.

In addition, the little egret, a rarer visitor to Ireland up to 1989, is now a resident Irish species and the blackcaps, which used to be summer migrants, are now over-wintering in Ireland.

Dr Donnelly encouraged the public to become involved in the National Biodiversity Data Centre. Its website (http://phenology.biodiversityireland.ie/) went live this week, allowing the public to help record the advent of spring.

The project is collaborating with Greenwave, which encourages primary schools to monitor the signs of spring, and biology.ie, its secondary-school equivalent.

Dr Jane Stout, a lecturer in botany at Trinity, said climate change was likely to lead to an increase in invasive species. She cited the Asian clam, recently found in the river Barrow in Co Carlow, as an example of an invasive species that might become more common in coming years.