Sap Flow

ὁ θεὸς ἡμέρη εὐφρόνη, χειμὼν θέρος, πόλεμος εἰρήνη, κόρος λιμός [τἀναντία ἅπαντα· οὗτος ὁ νοῦς, ἀλλοιοῦται δὲ ὅκωσπερ πῦρ, ὁπόταν συμμιγῇ θυώμασιν, ὀνομάζεται καθ’ ἡδονὴν ἑκάστου

“By cosmic rule, as day yields to night, so winter summer, war peace, plenty famine. All things change. Fire penetrates sap, until the joining bodies die and rise again in the taste of sweetness.”

– Heraclitus –

Its sugaring season here in New England, where the sugar maples are encouraged to redirect a portion of their sweet sap to drip into metal buckets that ring out in rhythmic percussion: Tap, tap, tap. The sap flow is a miracle that happens every year in these parts. Like most things in agriculture, sugaring is entirely seasonal and incredibly weather dependent. The sap could flow for two days or for six weeks. It all depends on specific variable temperatures to get the sap moving: above freezing during the day and dipping below at night. Sometimes this happens in March, or it could start in February when the land is just starting to slough off it’s insulating blanket of white.

Sunlight processed by the trees during the last growing season has been stored in the root system of the plant in the form of sucrose all winter long and is now compelled by the warmer climes and longer days to climb up the xylem layers underneath the bark during the day and flow back down to the roots during the chilling nights. This movement, reminiscent of blood flow, only happens in hardwoods with such intensity at this particular time of year. Though we know the climatic conditions that make sap flow possible, the actual mechanism in the plant that is responsible for the movement is still a botanical mystery. Unlike blood flow in animals, trees don’t have a heart that can pump liquid up and around the body. The current theory is that sap flow is caused by temperature induced changes in stem pressure, but that doesn’t explain why sucrose needs to be present for that to happen.

So, we speculate, we test, and experiment – but mostly we are grateful that we don’t have to understand everything that we are able to enjoy. We allow that the movement we tap into with our drilled holes, spiles, and buckets, is infused with magic; when we dribble the distilled amber liquid of Maple syrup onto our pancakes and waffles to start our days we acknowledge that mystery can be sweet, there is a beauty in the not knowing, and a delight in the possibility. How lovely that at a time when we most need a reminder that warmth and sunshine are just around the corner, the trees provide this elixir of life.