How do trees make sweet edible sap in spring? At the end of winter, sap of temperate broadleaf eudicot trees provides energy-rich sugars for animals and peoples of North America. Here, I conduct a multi-disciplinary synthesis to elucidate a theory of sap production and movement at a 'whole tree' level. I begin by contrasting settler knowledge to Indigenous knowledge of maples, and describe how "two-eyed seeing" may be used to address settler appropriation of maples and begin to decolonize maple provisions. Second, with a synthesis of scientific literature I show that sugars are not just byproducts of sap movement, but are signaling molecules that reveal a blurred functional distinction between xylem and phloem. I propose numerous predictions from my theory of sap movement. Finally, when testing whether spring xylem sap sugar concentration correlates with number of cells in the width of xylem rays I found significant positive correlation.