This poem is a love poem.  The poet is comparing the tent to the relationship he shares with the woman he loves.  Just as a tent stands tall in a field against the sun, his love is strong and is not simply based on one thing.

The tent is firmly held in place not by a single cord or string, but by a cedar pole that anchors it in place.  Frost tells his readers that love is a complex relationship based on countless ties that bind people together.

"Seems to owe naught to any single cord,
But strictly held by none, is loosely bound
By countless silken ties of love and thought" (Frost)