I have a rough idea of the location given that I've been looking at Google Earth and a booklet for photographer's but I'm still unsure of where it is?
Not a tree I have seen before, so not on the usual routes. Looking at the image I would guess here - https://goo.gl/maps/hSPQr6s15GjSbRub8 - but there are a hundred trees in the limestone to the South West that could also be possible, but this one seems to fit with the hint of a track in the background and should be about the right angle for the viaduct.
You going to give us a clue?
I don't wish to dampen your spirits but if the 'tree' is the one I am thinking of it isn't at Ribblehead but close to Malham Cove not far from Malham Tarn. Just a bit south east of Ribblehead The Malham cove one is well known and has appeared several time in Landscape Photography Year Books.