Of all the trees that are in the wood, the holly may well bear the crown. Sadly, it’s a crown that is now tarnished by ozone pollution.
All 400 species of the Christmas favourite could be affected, says Jonathan Ranford of Staffordshire University, Stoke on Trent, UK. Holly trees in northern temperate zones across the US, Canada and Europe are especially vulnerable, he adds.
Ranford and his colleague Kevin Reiling dosed European holly saplings (Ilex aquifolium) with 70 parts per billion of ozone – typical of peak summer levels in Europe – for seven hours a day, over a…
