Where treble has to do with threes, there is no substantive difference between it and triple. Treble is favored in a few specific contexts (in the game of darts, for instance), but triple is generally favored everywhere else. Even in British English, where treble is most common, triple appears approximately three times for every instance of treble. In American English, treble is almost unheard of except in relation to sound and music.
The proposal made public Tuesday more than triples the area proposed as critical habitat for the Mississippi gopher frog. [Houston Chronicle]
The desert nation plans to more than treble annual gas output to 230 billion cubic metres (bcm) by 2030. [Reuters]
Triple-check that the arm holes are large enough and positioned properly for your little trick-or-treater. [Cleveland Plain Dealer]
I always treble-check my passport after going to Las Vegas to do a BBC programme a couple of years ago. [Telegraph]
Twitter’s ad revenues are expected to triple this year. [Forbes]
Onslow, where the population is expected to treble, will receive a $250 million package. [Sydney Morning Herald]