NatureGround >> Envir. CEU or Cert. Programs

I have been wanting to get some certifications to help my career developement in the environmental field. From what I can find online, it seems you have to either enroll in a lengthy graduate program or many of the certs. require maintenance with further courses each year to stay certified. I am in the Chicago area and I know the Arboretum and Botanic Gardens have some rather generic cert. programs that require maintenance. I was hoping to find an Arborist certification program or something else worth while, even a course that takes several weeks is fine, but I don't want to be stuck with maintenance courses or years of night classes. If you guys can recommend online courses or cert. programs local to northern Illinois I would appreciate any input.