Ireland's Largest Tree of Heaven

The largest Ailanthus altissima in Ireland stands framed between two Victorian glasshouses in Dublin, and nobody agrees on how old it actually is. Trees and Shrubs Online, the standard international dendrology reference, records it plainly as the country's largest specimen of the species, 17 metres tall with a trunk over a metre thick, shaped well enough that one garden writer has called it among the most elegant of its kind anywhere in Ireland or Britain. The disagreement is about age. The Tree Council of Ireland's 2009 heritage survey bands it at 100 to 150 years, which would put it past 160 now, but Ailanthus altissima is naturally short lived and fast growing, a species where seventy years already counts as a good age in the wild. Both figures are given here rather than one being quietly dropped: either a sheltered, cared-for botanic garden specimen has simply outlived what the species usually manages on a roadside or waste ground, which is plausible, or the register's band runs generous. What is not disputed is the position, framing the view toward the Palm House and Curvilinear Range, the garden's twin 19th century glasshouses, and the species itself, native to China, notorious elsewhere as an aggressive street weed but planted here deliberately, long before anyone thought of it that way.