Interesting idea. Positive fun feedback for staying focused! A few things: the app is called Forest but the HN post title is Forrest. What is "phubbing"? I've never heard that word before and I suspect most people would not have. Do you mean distracted, and if so, why not say that?
It would be fun to be able to convert concentration points into other things for the forest: animals running around, flowers, progressing the seaons. Maybe an autumn season will approach if your month-to-month productivity starts to fall. :)
