I heard a story about a guy who applied for a job with the BTCV (British Trust for Conservation Volunteers). When he arrived for the interview he was presented with leafless twigs from 20 different trees to identify. He got two wrong but was still given the job.
The fact is that if you are leading a winter conservation task with gung-ho volunteers you don't want them cutting down any rare trees such as Wild Service (Sorbus torminalis).
I do know a woodland owner in Essex, who shall be nameless, who on purchasing their woods did cut down their only notable tree and got me to identify the regrowth from the coppice stump...It was a Wild Service and they had thought it was a Sycamore (Acer pseudoplatanus).