How does dougie maclean tune his guitar on broken wings?

Dougie MacLean tunes his guitar for "Broken Wings" to an open D tuning, which typically consists of the notes D-A-D-F#-A-D from the lowest string to the highest. This tuning allows for a rich, resonant sound that complements the song's emotive qualities. It also facilitates the use of fingerstyle techniques, enhancing the overall texture of the performance.