Your logo looks good in black and white, which also means it's a good design. You know that it will fax well, and if you ever need to make a stamp out of it, the design will be a good one. If you ever get to that point, I suggest that you get rid of the little horizontal lines in the tree trunk, since I don't think that will show up in the stamp. I would get rid of the rectangle though. I think that will open it up more and won't feel as confined. I would just color the tree a different solid color. If you want to do monochrome, you can take a base color and then do color percentages of it. If you get these professionally printed, it will save you $$$, because it's still technically a one color job that they're doing.