Is it my responsibility to clean up branches and tree trimmings after my landlord cut them down?

Ok ever since December of 2008 when I moved into my house,my landlord has kept a trampoline in the backyard and had natural debris under it,he also had cut down a small tree and placed it under the trampoline. Well yesterday the landlord came and removed the trampoline and trimmed the trees,he then left without cleaning up the natural debris he had under the trampoline,and without picking up the branches he had trimmed. I called him to ask when he was going to clean it up and he stated it was my responsibility that I live here,I replied that it is not. He then called me tonight to tell me he was writing up an eviction letter. Can he do that? In my lease it states that I must keep the lawn,shrubs and hedges in good order,well what does that mean,because it does not specify exactly what good order is. I live in Maryland just so you know.