I like
Glacial Chasm in this deck, you can even
Crop Rotation for it.
I'm digging
Painter's Servant +
Grindstone as another win con in this deck. The reason is that Servant specifically naming Black makes
Lifeforce,
Nature's Wrath,
Reap,
Elephant Grass great. The
Nature's Wrath would be symmetrical but you have lots of token makers so can get around it fairly easily.
Caustic Caterpillar and
Seal of Primordium are excellent with
Dosan the Falling Leaf to give yourself instant speed removal.
I like
Kenrith's Transformation over
Lignify as it draws you a card.
I'd play
Spike Weaver. I feel like your instant speed Fogs might be a bit too much of a nonbo with
Dosan the Falling Leaf.
Nissa, Who Shakes the World over
Vernal Bloom so that you don't fuel other Green decks and you can also work towards putting all your lands into play and indestructible at that.
I do think the deck lacks card draw or more ways to gain resources in general.
Beast Whisperer,
Ohran Frostfang,
Eidolon of Blossoms,
Oakhame Adversary,
Regal Force are going to be welcome additions.
Temur Sabertooth bouncing
Regal Force is one of my fav big draw multiple times things to do in mono-green.
Of note Sabertooth could bounce some of your enchantment creatures for multiple draws off
Beast Whisperer,
Eidolon of Blossoms,
Argothian Enchantress. So for example bounce
Destiny Spinner to draw cards if you are step up.
Garruk, Primal Hunter to draw cards, plus he is another win condition.
This deck looks pretty grindy so
Seasons Past can be an all star in games that see a lot of back and forth.
Growing Rites of Itlimoc // Itlimoc, Cradle of the Sun is a good ramp card and even if you don't flip it until a later date, it replaces itself and another enchantment for
Argothian Enchantress (and
Eidolon of Blossoms).
As far as cuts for cards I suggested
Biogenic Ooze - deck has plenty of win cons.
Ichneumon Druid - seems very situational to do damage, if at all.
Dawnstrider,
Constant Mists,
Arachnogenesis -
Glacial Chasm and
Spike Weaver take up these roles instead.
Gaea's Touch - Maybe if you have
Oracle Mul-Daya in the deck, but otherwise your actual draw in the deck is still marginal even after my suggested additions.
Krosan Restorer - mehh
Curious Herd - the deck has enough win cons and has a nice handle on artifacts, so you don't want to be punished for low artifact count games.
Skullwinder -
Seasons Past instead.
Dungrove Elder,
Timber Protector,
Wickerbough Elder -
Caustic Caterpillar and
Seal of Primordium will take up the role of
Wickerbough and the Treefolk theme is too narrow. I get that you can make Forests creatures with
Destiny Spinner but again narrow.