So recently I was talking with Gauss over Skype about the Treesinger archetype. He went into great length on explaining, how the class is inferior to the traditional druid, focusing mostly on the aspect of the plant companions against animal companions.
And here comes my question... How are bonuses calculated exactly? I have access to only a few PDFs, as my GM did not share all of the stuff, just what we needed at the time. And Core Rulebook says "Bonus: Bonuses are numerical values that are added to checks and statistical scores. Most bonuses have a type, and as a general rule, bonuses of the same type are not cumulative (do not “stack”)—only the greater bonus
granted applies." But... What of bonuses that have no type? What of permanent effects to a certain aspect of the character?
To make things simpler, I will try to focus on the druid's Treant Sappling, and it's Natural Armor specifically, as this is what I was researching about. So on lvl 1 it has +1 Natural Armor Bonus. Which I belive means, that it's AC is increased by 1 due to the Treant Sappling having some natural hardness to it. On lvl 3 it gains +2 from the companion progression, which I belive adds up to +3 total. On lvl 4 it's growing to Large size and gains another +2, which I assume adds up to 5 Natural Armor Bonus. Now here comes my question...
1) Let's say the Druid in question chooses the Evolved Companion feat and uses the Improved Natural Armor lvl 1 evolution for the Treant Sappling. It's a +2 Natural Armor Bonus without a classification, it's permanent, so once more I would assume, it would merely add to the Natural Armor of the Treant, making it 7. Or does it remain 5+2 bonus?
2) Let's say the Druid in question uses Animal Growth on the Treant Sappling, making it grow from Large to Very Large (? I am not sure what's the next size ?). The spell itself adds another +2 to AC and the size increase will make it lower by -2 once more, thus the AC will not be affected, remaining at 5. Am I correct? Again, would the -2 affect the +2 of the spell, or considering the Evolved Companion was chosen, would it actually be a -2, because only one bonus applies?
3) Let's say the Druid in question chooses the Evolved Companion with Improved Natural Armor and casts Barkskin on the Treant Sappling. The Barkskin says clearly, it's an +2(or more) Enchantment Natural Armor Bonus. It's named and classified, so I would assume that it does not clash/colide with Natural Armor Bonuses of other types and/or unnamed?
1) Your first assumption is correct, a +7 natural armor bonus total to its AC. Each of those bonuses to Natural Armor are "Typeless" and typeless bonuses stack together.
2) As pointed out, Animal Growth won't work on your treant because it is a Plant creature and not an Animal creature. If it did, the treant would grow to size Huge and AC would not be changed because the bonus to Natural Armor from the spell is also typeless.
3) Correct, Barkskin gives an Enhancement bonus to Natural Armor, so it will stack with each of the typeless bonuses. If your treant ever got an enhancement bonus to natural armor from some other effect, only the greatest of the two would apply.
Actually, Animal Growth can be cast on a plant companion. Except for being plant creatures and being selected from a separate list of companions, plant companions work exactly the same as animal companions. And the animal companion's share spells special ability allows it to be the target of spells that don't normally target its creature type cast by the druid.
Okay, I get it. If say... I have some magical artifact that gives me +1 Str enhancement bonus but someone uses a spell that gives me +4 Str enhancement bonus, I will only get a +4.
So... Now I only need to find out what are the bonuses and how to stack them. Time to read about magical items.
PS.
Treant Sappling counts as normal animal companion for any spells and effects coming from the druid. As well as can be the target of spells that don't normally affect planta nor animals.
Ah, forgot druids got share spells on their companion.