Yes, BOURTREE is a Scrabble word!

Letter values in Scrabble US: B 3, O 1, U 1, R 1, T 1, R 1, E 1, E 1.

Is it a valid word?

BOURTREE is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a common shrub with black fruit or a small tree of Europe and Asia; fruit used for wines and jellies

Also: black elder, common elder, european elder, sambucus nigra.