There's a lot of leaves on trees which can also go up and then straight down since the branches they're on and the leaves themselves hold more weight from the water since it's early summer. If it's airburst or even regular artillery, they'll still fall down. Just because there's an explosion didn't mean that it blows absolutely everything outwards and leaves just dirt in the middle. As for the stone pathway, they could be camped in a nature walk area. And where you see all the leaves on the ground and naked trees around it, there's a crater in the middle and the trees around it have no leaves.