Unfortunately, after gathering resources with no available space in the warehouse some of the resources can fall on the ground. We can't influence where the resources will fall and sometimes they may get stuck behind a big tree or a huge rock.
We recommend that players gather resources with available space in the warehouse. You can save up more energy to cut down a tree or move a rock.
Tip: if you want to collect a lot of energy, feed the family first and collect the energy from the chests/merchant/shaman/gifts/energy packages afterwards.