So, here's how it turned out... just in case you were curious.
by the end of the year each classes poster board will be filled with stickers, stamps, and signatures of all the kids during their birthday month.
Thanks for the tips on the trees...I like the way they turned out, wrinkling the paper was good therapy (if you know what i mean?)
now my only concern is that it's not screaming BIRTHDAY... but oh well!