[R] superscript in figures - basic question

[Benjamin M. Osborne]

Although I see similar, but more complex, questions addressed in the help
archive, I'm having trouble adding superscripted text to the y-axis labels of
some figures, and I can't find anything in the R documentation on this.

I have:

ylab="BA (m2/ha)"

but I want the "2" to be superscripted.
Thanks in advence for the help, or for pointing out the appropriate help file.

-Ben Osborne