The game can only remember the 10 most recently-struck trees at a time. After the 11th tree is hit, the 1st tree's state is wiped from the memory and can be harvested again. However, if a previously harvested tree is struck again BEFORE this, it will be moved back into the sequence as the most recently updated item. Therefore, a loop in the following order where each number represents a specific tree will generate no wood on the second partial loop: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. This is because trees 2-11 have become the recently updated set in memory, and only 1 has been dropped and reverted to "harvestable" state. In a typical 11 tree loop, hitting tree 1 again would provide wood, then remove the most recent last tree (tree 2 in this case) from memory. Partial harvests also count the same as full harvest or re-harvest.