I confirm. I was collecting scrap leather, i had the first 4 piles seperated into items, and was just take a rest with "Sit Down Option" when i stand up again and collected the next Leather. But instead of a Leather, a giant Tree appeared in front of me and my backpack showed a grey Box.
28 March, 2011, around 16:30
I asked other People, they all confirmed to see the tree in front of me. I just discarded it now and took severel screenshots. In the Screen you see at the right middle side the inventory box and my mouse over the grey "no image" box show the name of the tree "Felled Weeping Willow"