By David Beamish
The species known rather charmingly as the Tree of Heaven, Ailanthus altissima, is said to derive its name from its tendency to grow to a great height. Its generic name Ailanthus is related to an Indonesian word meaning “a tree reaching the skies”, and altissima is Latin for “highest”. It is a deciduous tree originating in the Far East, with pinnate leaves - leaflets either side of a stalk, like the ash, rowan and walnut - readily identifiable by a distinctive single tooth on each side of the base of the leaflet. The small yellowish-green flowers appear in clusters in mid-summer.
The species was introduced to Europe, initially in France, in the middle of the 18th century. In 1751 seeds were sent from there to the superintendent at the Chelsea Physic Garden. It is usually dioecious, that is to say with male and female flowers on separate trees.
There are several examples to be seen in Dulwich. A large mature example is on the western (Delawyk Crescent) edge of the grounds of the Judith Kerr School in Half Moon Lane. There are three or four in Dulwich Park, of which the easiest to find is perhaps the young tree just opposite the car park entrance. There are also examples in some Dulwich streets, including Friern Road (outside Nos. 295-341) and College Road (at the junction with Stonehills Court).
While a mature Tree of Heaven can look impressive, the species generally gets a bad press. Wikipedia refers to it as “a noxious weed and vigorous invasive species, and one of the worst invasive plant species in Europe and North America”. It spreads aggressively both by seeds and vegetatively. The sapling in the photograph was spotted beside College Road in autumn 2021. Collins Tree Guide describes the leaves as “malodorous” and the male flowers as “stinking”. It is perhaps understandable that it no longer seems to be commonly planted in London parks or streets.