Updated for Modern!
So it used to be a vintage or whatever casual tribal deck with Doran, the Siege Tower and Armageddon + Timber Protector
(sounds fun I know :D). This has been changed! Now it's still a nice casual deck and it's modern legal \o/
But Seriously, Treefolk Harbinger alone make it worth to play this tribal and I still believe it's one of the strongest tribal synergy they made (of course there are stronger ones like elves). It's (or was) so slow, though! That's why I updated it with Skinshifter, Courser of Kruphix and Mwonvuli Acid-Moss
Changes:
Mwonvuli Acid-Moss -1 -> Rolling Spoil +1 : Helping with potential multi-threats. Snakeform and Assassin's Trophy are the preferred cards agaisnt bigger threats.
Snakeform Mainboard -> Sideboard
Skinshifter +4 -> Llanowar Elves moved to maybeboard: Bringing back Skinshifter for testing as I remember it was such a versatile 2-drop to have in treefolk/shaman (it shares the shaman subtype). I'm expecting that the elves are too useful to be removed but I'll do further testing. It's usefulness here: it can ping damage as a bird; it might be able to do some trample or at least become a menace since it can be a 4/4 at anytime; but the best value is in it's 0/8 Plant form, paired with Doran, the Siege Tower. It's also part Shaman so it can trigger Leaf-Crowned Elder, while the elves will not. I believe than with Courser of Kruphix, Treefolk Harbinger and Mwonvuli Acidic-Moss it might be enough mana ramp; I also added Indatha Triome as both a forest land that has all the needed colors and a potential cycling card. This is still a slow deck in any scenarios though so I prefer versatility in this case. Remember this is not a competitive deck!
Veil of Summer instead of Autumn's Veil
+3 Courser of Kruphix : In this deck, where you get to put forests in top of your library, it's basically a free land draw. The bonus life looks negligible but it's actually a big help. It's also a 2/4, which works perfectly with the overall deck with Doran, the Siege Tower. It also works wonders with Leaf-Crowned Elder and Dauntless Dourbark
+4 Beast Within > Bramblecrush for instant cast value, a 3/3 with no ability shoudln't pose much of a threat for a tougness creatures deck
