Answer :
pine trees
The narrator's neighbor is growing pine trees. The narrator is growing apple trees. In the poem, the narrator says, "He is all pine and I am apple orchard.
In Robert Frost’s poem “Mending Wall,” the narrator's neighbor is growing pine trees while the narrator is growing apple trees. In the poem, he says:
"He is all pine and I am apple orchard.
My apple trees will never get across
And eat the cones under his pines".
Those lines prove that the neighbor is growing pine trees and the narrator is growing apple trees.
"Mending Wall" is a poem by the twentieth century American poet Robert Frost.