You could say to your customers "Well,I don't know, I love that tree so much...I'll let it go sniffle sniffle.. for 2000 bucks. Take it before I change my mind."
I'm stealing that one, LOL! I'm also going to greet EVERYONE with a "Happy Earth Day!" that day.
I'm encouraging the kids (nieces & nephews that are always underfoot) to set up a little stand and make up pitchers of green Kool Aide and sell it as "Earth Day Juice." Maybe we'll bake chocolate cupcakes with green and blue frosting and sell them as "Earth Cakes?" LOL! We'll see how motivated they are. ;)
That's the spirit! Ham it up. Mutter things like "Everybody needs to carry their weight but they aren't so we "Earth" people need to carry more, buy more trees." "Spending all the proceeds to grow more trees." "Surely you can find space for another tree."
Hope you have a great day and I hope the weather's nice. I figure you're out in now.