InstancedFoliageActor Problem

Hey there,
So i’m kind of new to the whole ue4 thing and i have a pretty big problem with my foliage. I’m doing a nice and big Landscape for a school project and i wanted to build the lighting. In the Message Log were a couple(23) of problems with the lightmap size. I have a huge foliage over the entire map so it is pretty heavy on the performance(culling is on). In the picture is the Message Log…i don’t know what to do here. Can somebody help me out here?
Thanks!