tmpar <- par(mar=c(3,3,0,0),mfrow=c(1,2))

int.plot( growth.full, xpos = 2.5, ypos = .425,
   xaxt = "n", xlab = "", ylab = "" )
mtext( "(a) BA by TDZ", 1, 2 )
axis( 1, 1:3, c("0","0.44","4.4") )

int.plot( growth.full, fac = c("tdz","ba"), xpos = 3.25, ypos = .425,
   xaxt = "n", xlab = "", ylab = "" )
mtext( "log(1 + advplt)", 2, 2 )
mtext( "(b) TDZ by BA", 1, 2 )
axis( 1, 1:4, c("0","0.2","2","20") )

par(tmpar)