The impact of the dry season is still evident in the landscape after almost three months. The forty shades of green of late spring have turned to as many shades of brown and yellow as grassland has prematurely shrivelled and early harvesting of crops such as winter barley has created premature landscape patterns.

Forests are also vulnerable to drought with the added risk of fire which continued beyond the traditional danger period of February to April up until last weekend when finally most of the country experienced some rainfall.

Drought

Trees are “engineered” to cope with dry spells better than seasonal crops because of their deep rooting ability to seek out available water. The amount of water required by trees varies with species and location. Individual trees in fields and parklands will require more moisture than forest or woodland trees because of their larger canopies.

Water uptake by trees will also depend on the site and soil conditions as well as the age of trees. Trees planted this year, or even in recent years, have yet to develop a fully formed rooting system so are vulnerable to drought.

Padraig Egan of SWS Forestry said there are some losses already in this year’s planting and while it is too early to assess plantations established over the past four years (the time scale between first and final grant payment in the Afforestation Programme) he said there will be losses. “We will need to carry out some filling-in [plant replacement] to ensure fully stocked plantations because of the prolonged dry period but conditions vary from site to site. For example, trees planted on damp rushy sites are performing very well while trees on exposed shallow mineral sites are under stress.”

John O’Reilly, Green Belt said that trees planted up to late April have experienced little or no rainfall in some parts of the country. “Some conifers are under pressure and broadleaves – especially birch – will need replacing,” he said.

Readers may have noticed that even semi-mature birch seems to be suffering from drought from observing the species in roadside and garden sites. “Deep rooting native species such as oak and ash are unaffected by the dry spell but birch, which is a relatively shallow rooting species, can be affected by prolonged drought,” said Dr Matthew Jebb, director, National Botanic Gardens, Glasnevin. He added that closely planted trees resulting in competition for available nutrients and moisture can increase the onset of damage which may continue beyond the current growing season.

“Trees such as birch which are under severe stress at the moment may survive this year’s growing season,” he said but urged caution about their future survival. “Some trees may again show signs of stress during the following summer, even though there may be ample rainfall in the intervening period but the damage has been done. There may be a delay until the fourth year before some trees eventually die.”

While tree health and survival are relatively easy to monitor in arboreta, gardens and parklands, they are more difficult to check in forests and woodlands because of scale and more densely planted trees. Trees are resilient but young plantations need to be checked as filling in may be required this autumn while plantations established over the past four years also need monitoring because of the delayed damage mentioned by Dr Jebb.

While some recently established plantations may have major failures, most foresters contacted said it was too early to say if a reconstitution grant payment will be required. Unlike tillage farmers who may have opportunities to “go again” this year by planting forage crops such as fodder rape, stubble turnips or other green cover crops, forest owners are obliged to continue managing their forest and ensure stocking levels are optimised for rotations that may extend to the next century for species such as oak and beech.

Fire

The fire danger period normally ends in early May as fresh growth of grasses and plants replaces dead and combustible vegetation. While the records will probably show that 2018 was one of the driest summers in recent times it will also show that the incidences of forest fires were low especially compared with 2016 and 2017.

This year, rainfall was high in the spring so forest fires were minimal. While ground vegetation was scorched from May to July, the cold dry winds that fan the flames during harsh spring conditions are rarely experienced during the summer months. However, there were fires, some of which have caused serious damage although small in scale and there were also near misses. Paul Brosnan of Veon Ltd, which has been at the forefront of the campaign to minimise forest fires with Ibec, said that the company’s forests escaped the widespread damage caused to state and private forests last year but like other forest companies the fire threat remained for most of the year. “For example, we controlled a bog fire recently – helped by some welcome rain – before it reached one of our forests in Co. Kildare, which would have been disastrous,” he said.

Padraig Egan, SWS Forestry agreed that the incidences of fire damage were low this year. “We had a few fires in clients’ forests but the largest was 4ha, “ he said. “I think the public and landowners have reacted responsibly to warnings about careless burning which is a positive development.”

Pat Neville of Coillte was relieved that the company’s forests had escaped the catastrophic fires of 2017. He said they had controlled a number of isolated forest fires around the country but ironically just as the dry period was coming to an end the company faced a serious fire in the Slieve Bloom Mountains which has some of the largest contiguous forest blocks in Ireland.

“We have just extinguished a fire in the Slieve Blooms which jumped a fireline but our staff controlled it at the second firebreak, helped by the fire services and Air Corps,” he said. He maintained that timely intervention and the construction and maintenance of firebreaks were essential in minimising forest fires.