I saw the following problem and was looking for references about the problem. The problem is stated as
“The green field is the empty area, the dark green 2x2 blocks are trees and the grey area is the off area. I’m wondering how to place the blocks in the field, while cutting the least amount of trees.”
with a picture (I've reduced the size)
As far as I can tell this is related to square packing (https://en.wikipedia.org/wiki/Packing_problems#Packing_squares) but there is the related problem of minimizing the number of trees cut. I also found this Stack Exchange answer which suggested some approaches (https://stackoverflow.com/questions/1213394/what-algorithm-can-be-used-for-packing-rectangles-of-different-sizes-into-the-sm) but it doesn't fit exactly.
Any insights would be useful.