A max fine of $3000 -$6000 per tree! That's tiny. Tree law in the US is brutal. If you illegally cut down a tree you owe the amount it would cost to have a tree of that type and size replanted there (those didn't look like small trees). If the tree is too big to feasibly replant an equivalent one there then generally you owe $2000 per year that tree had been growing. So if you cut down someones 100 year old tree then you owe them $200,000. Although the exact numbers may be changed now because I haven't had to look it up in a while.

With something like this someone needs to be bankrupted over it. A couple million dollars to a big developer is nothing. With something like this they should literally have to pay to replace all of those trees with identical ones plus punitive fines. Also how did noone see who did it? That's a pretty big landscaping effort for nobody to have seen anything. They also had to have taken the trees somewhere. There's no way that nobody saw anything. No traffic cams saw trucks carting 300 trees out of the area?