By Susan Jenkins, The Tree Company
After our unusual and late blast of snow we welcome back the incoming spring. Our official spring this year started on March 20, the vernal equinox, when the earths’ orbit around the sun means that there are equal amounts of day and night, as the orbit rotates the season will change again on June 21.
Snowdrops, daffodils followed by bluebells and wild garlic will soon emerge following the pattern laid down by natures’ incredible clock. Buds on our trees burst their seals and the new leaves emerge but not all at the same time. The land is greened in an organised system, the series of growth spurts; an evolution of biodiversity timed to coexist in a complementary way. The triggers to this growth pattern are temperature and light so the signals of spring occur across Ireland at slightly different times depending on these two main catalysts.
We all enjoy marking the many signs of spring, some we are more aware of then others: the first flowering primroses, frogspawn, first cuckoo calls, birds building nests and then of course the arrival of the swallows. The study of observing and documenting these natural events especially in relation to climate is called phenology.
Phenology is simply collecting the data of these seasonal indicators in a methodical way, looking at the same flora and fauna each year building up a catalogue of reference which scientists can use to aid farming processes and monitor the effects of climate change.
Phenology in Ireland began early in the 20th century when these observations of phenological events or ‘phases’ would feature in the Irish Naturalist’s Journal and a more methodical system was established in the 1960s as part of the Europe-wide International Phenological Gardens (IPG) network. In Ireland four sites were designated to collect this data from, in each of them a special group of trees grown to create the ‘test’ batch of like for like results and readings, they are in Valentia, Co Kerry, JFK Arboretum, Johnstown Castle in Co Wexford, and the National Botanic Gardens in Dublin.
For spring it’s especially the timing of each trees bud burst that is the indicator required, this is when the bud case finally breaks its clasp on the new leaf breaking out and the soft new growing leaf slowly unfurls, its almost like the butterfly emerging from its chrysalis. Bud burst is usually early if the temperature is warm and late if the temperature is cold. This data has become more relevant with regard to climate change in the last 30 years with some tree species bud bursts occurring earlier and earlier each year. Data is illustrating that the warmer temperature changes are particularly having effects in Ireland more so than the rest of Europe on native species such as lesser celandine, wood anemone and hazel indicating this.
So maybe this spring become a phenologist officially! There are many sites and organisations calling out to the public for their seasonal observations to fill important information gaps for their records from every location to add to the larger and growing European database formed of 90 official sites now in 20 countries. Some might collect data on everything or some might want more specific groups such as butterflies, ladybirds or particular birds or flora. You might like to check out the Trinity College Phenology web page or www.biology.ie or www.biodiversityireland.ie.
Whether you have your clipboard in hand or not, enjoy observing the most joyous of seasons and marvel at all those buds bursting out and greening our landscape with their own remarkable and powerful life force.
If you need any further information regarding this article or indeed any other tree matters please get in touch with us at The Tree Company, Ballydehob, Co Cork or email us at firstname.lastname@example.org or call our office on 028 37630.