Data values 0-3 are the regular logs, 4-7 are the sideways ones on the x axis (or is it z), 8-11 are the sideways ones on the other axis, and 12-15 have bark on all 6 sides. Keep in mind that they'll just change to the correct angle when placed unless you use setblock to place them. You probably used 4 when you meant 3.
Data values 0-3 are the regular logs, 4-7 are the sideways ones on the x axis (or is it z), 8-11 are the sideways ones on the other axis, and 12-15 have bark on all 6 sides. Keep in mind that they'll just change to the correct angle when placed unless you use setblock to place them. You probably used 4 when you meant 3.