Sylvan Hermitree

The monster effect "Once per turn, during your Main Phase: You can excavate the top card of your Deck" is an Ignition Effect. (This effect does not target.)

If the card excavated by the monster effect "excavate the top card of your Deck" is a Plant-Type monster, the effect "if it was a Plant-Type monster, send it to the Graveyard and draw 1 card" is applied. (If it was not a Plant-Type monster, the effect "if it was not, place it on the bottom of the Deck" is applied.)

The effect "send it to the Graveyard" and the effect "draw 1 card" are considered to happen simultaneously.

The monster effect "If this card is excavated from the Deck and sent to the Graveyard by a card effect: You can look at up to 3 cards from the top of your Deck, then place them on top of the Deck in any order" is a Trigger Effect that activates in the Graveyard. (This effect does not target.)

The monster effect "look at up to 3 cards from the top of your Deck, then place them on top of the Deck in any order" is a mandatory effect that activates when "Sylvan Hermitree" itself is excavated from the Deck by a card effect and sent to the Graveyard as a result of that effect's resolution. (It also activates during the Damage Step.)