Using xNormal I was able to create these normal and ambient occlusion maps so that my low-poly model has a similar amount of detail as my highpoly model, without having the same memory draw.

Base_Normals/Ambient Occlusion

Top_Normals/Ambient Occlusion

Tree1(A)_Normals/Ambient Occlusion

Tree2(B)_Normals/Ambient Occlusion