The Port Talbot pollution has killed the trees.
Peter Kerslake says "Located within the Port Talbot area of South Wales, for many years the centre of Welsh steel production, the depot at Duffryn Yard was opened in 1896 when the Port Talbot Railway constructed a five road centre to which was later added a sixth road by the G.W.R. in 1931 for the large and increasing number of Tank Engines of various classes allocateded there, with fifty or so on its books during its heyday; the depot closed in March 1964."