It is flowers of the forest, although not a particularly well known tune outside of a) Scotland or b) the military. I don't think it is particularly old, only about 100 yrs or so, give or take a decade.... It is regarded as the Scottish 'Last Post' the tune played over every Scottish war grave or act of remembrance where possible. It has its roots in the playing of the forbidden pipes at the wake for a slain Scottish fighter way back in Edward Longshanks' time - although as pointed out on threads here before, the pipes played in Braveheart over the grave of Wallace snr, are not highland pipes, but bellows pipes.....

LTS