Last March of the Ents

This spell can't be countered.
Draw cards equal to the greatest toughness among creatures you control, then put any number of creature cards from your hand onto the battlefield.

Rootgrapple

Destroy target noncreature permanent. If you control a Treefolk, draw a card.

Treefolk Harbinger

When Treefolk Harbinger enters the battlefield, you may search your library for a Treefolk or Forest card, reveal it, then shuffle and put that card on top.

Harmonize

Battlewand Oak

Whenever a Forest enters the battlefield under your control, Battlewand Oak gets +2/+2 until end of turn.
Whenever you cast a Treefolk spell, Battlewand Oak gets +2/+2 until end of turn.

Dauntless Dourbark

Dauntless Dourbark's power and toughness are each equal to the number of Forests you control plus the number of Treefolk you control.
Dauntless Dourbark has trample as long as you control another Treefolk.

Quickbeam, Upstart Ent

Whenever Quickbeam, Upstart Ent or another Treefolk enters the battlefield under your control, up to two target creatures each get +2/+2 and gain trample until end of turn.

Entish Restoration

Sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle. If you control a creature with power 4 or greater, instead search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Wickerbough Elder

Wickerbough Elder enters the battlefield with a -1/-1 counter on it.
{G}, Remove a -1/-1 counter from Wickerbough Elder: Destroy target artifact or enchantment.

Fangorn, Tree Shepherd

Treefolk you control have vigilance.
Whenever one or more Treefolk you control attack, add twice that much {G}.
You don't lose unspent green mana as steps and phases end.

Forest

Orchard Warden

Whenever another Treefolk creature enters the battlefield under your control, you may gain life equal to that creature's toughness.

Lignify

Enchant creature
Enchanted creature is a Treefolk with base power and toughness 0/4 and loses all abilities.

Asceticism

Creatures you control have hexproof.
{1}{G}: Regenerate target creature. (The next time it would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Leaf-Crowned Elder

Kinship — At the beginning of your upkeep, you may look at the top card of your library. If it shares a creature type with Leaf-Crowned Elder, you may reveal it. If you do, you may play that card without paying its mana cost.

Bosk Banneret

Treefolk spells and Shaman spells you cast cost {1} less to cast.

Dungrove Elder

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Dungrove Elder's power and toughness are each equal to the number of Forests you control.

Rancor

Enchant creature
Enchanted creature gets +2/+0 and has trample.
When Rancor is put into a graveyard from the battlefield, return Rancor to its owner's hand.

Timber Protector

Other Treefolk creatures you control get +1/+1.
Other Treefolk and Forests you control have indestructible.