It's actually F5. But, its great to have it in full-screen! How do I break down bushes into sticks? I can sort of read the Guide if I go into the Save file and peruse guide.ini However, I've tried interacting with bushes and trees with everything I can think of and I don't get any sticks. Thanks!
Unfortunately there's not much I can do to help, as I no longer even have the source code for Erth. Your best bet is to just look at the guide .ini file and figure it out from there. If you have any more questions, feel free to ask!