mapelem.dat decoded
It contains an array[254] of
{
short[30] Animation;
short Count;
int X, Y;
Boolean Choppable;
Boolean UnWalkable;
Boolean Unknown;
Boolean Vineyard_or_Cornfield;
Boolean Growable;
Boolean PreservePlantingDistance;
sbyte TreeTrunk;
Boolean Buildable;
}
There are two things I should note, the booleans are saved as integer and have the value 1 for true and zero for false. Secondly, the boolean Growable is also true for treetrunks, which is a little unexptected.
Then there is only one boolean undecoded, and I've assembled an image containing the textures for which this boolean is true, and as you can see the boolean probably doesn't mean anything important. Feel free to guess in what way the textures in that image are different from all others.