A program for calculating the strength of the guard on random maps in Heroes of Might and Magic III, called H3CalcGuards.

Level 1 art, so it's always a quest item for that kind of guard, and its value varies depending on the reward (it's set in the seer's hut program and the reward). If the reward is monsters, then you need to consider the number of zones with cities for that type of monster. Regarding the tree with flies - I haven't looked at the save, but are you sure there isn't any unobserved resource under the mountain?