Another googleabout reveals that The Ancient Order of Foresters had beadles who carried horns, which at least connects the two words. These were bugle-like cow horns, and seem to have looked like this:

http://www.tennants.co.uk/Catalogue/Lots/175501.aspx

More info is below. It doesn's sound very lulling, though - the only thing I can think of is the end-of-day "taps" idea, with its "all is well, safely rest" theme, which I suggested above. But in the context of this song, that's only a guess.

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'In Forestry the word 'court' is used instead of 'lodge', derived from the law courts of the of the royal forests , which since the Middle Ages had met to administer the special forest laws. Similarly the officers of the society used the titles of officials of the medieval forest courts, such as Ranger and Woodward. Thus the chief official was the Ranger. Courts were guarded by two Beadles, and a Senior and Junior Woodward, whose job was to serve all summonses, visit the sick, dispense allowances and take charge of all court property. The regalia of the Beadles included huge cow horns (real cow horns) [elsewhere described as "bugle horns"] slung from the left shoulder, and axes; each Woodward carried an axe.'

http://www.epsomandewellhistoryexplorer.org.uk/Foresters.html