For this shot specifically, we faced a lot of issues with our render time per frame. It was coming out to be a lot higher than what we needed to meet our deadlines due to the amount of grass and trees. I needed to optimize the scene and did so by creating multiple render layers based on distance from camera. I then reduced samples as the distance increased and compromised considering the depth of field that would be added in compositing. This cut down our render time considerably and I was able to composite the shot in nuke.