By my window have I for scenery
sea with a stem
The pine tree becomes an ocean turned vertical. Dickinson refuses the ordinary word, forcing you to see the tree as waves of green needles.
quotation marks
Those scare quotes around "Pine" reject the farmer's utilitarian view. She's saying: your word is inadequate for what I'm seeing.
giddy peninsular
The branch becomes geography—a peninsula jutting into air. "Giddy" because the squirrel is high up, but also dizzy with the vertigo of height.
commerce of spice
Pine resin smells like trade goods—frankincense, myrrh. She's making the tree into an economy, a merchant ship carrying aromatic cargo.
dumb divulge
"Dumb" means mute—can something without speech reveal God? The pine's wind-sound is language without words.
definition is none
True melody can't be defined—it exceeds language. Same logic she's applying to the tree: the real thing escapes all names.
Royal Infinity
Capitalizing makes infinity a kingdom, the pine a member of divine aristocracy. "Fellow" suggests companionship, equality with the eternal.
Apprehensions
Double meaning: both fearful awareness and acts of grasping/understanding. God introduces himself through moments of startled recognition.