Will a simple high school diploma do or am I gonna have to get some higher education? There aren't that many (good) job opportunities where I live, but I heard that one place is in need of more forestry technicians.

You probably need some kind of college diploma to get a job like this. Just call the place you're looking at and ask them what kind of qualifications you need to work for them and how to get them, they'll point you in the right direction and maybe even remember you when you come back a in a few years.

per BLS you'll usually need an associate's degree to be a technician, but there are some lower-skill positions where a high school diploma should be enough. i'd say just ask the place like the other guy said. in general you could also spend the extra couple years to get a related bach degree and boost the salary a lot by doing more forest science type stuff