OK, enough! This is my area of expertise. If you are seriously marking trees/timber, you need TREE MARKING PAINT. It has a different formulation and won't be sucked up into the bark so you'll use less. There are several colors available commercially. Blue is the most commonly used for cut tree designation. My preference? PINK. Our guy markers won't use it because, "I don't want pink paint on my clothes." However, the manly factor is high because those godlike creatures, the best of the best (quote from the Axemen show), the Helicopter Fallers were prancing around the woods painting cut trees with.......PINK tree paint. We all liked it, it stood out and was as cheery a color as blue. Don't forget to paint a stump mark, at ground level so you can see that the correct tree was cut.