after being registered as a trademark, you can exclude others from using the same or similar trademark on the same or similar goods, but you can't exclude others from registering or using the same or similar goods (although you can object with copyright, it is difficult to prove without registration).
It's relatively high to register and protect trees in all categories. This is the best way to register them by copyright, so that others can be excluded from registering them as trademarks.
However, not all trademarks can be applied to copyright registration. I hope my answer will help you. Thank you.