A Drop in the Bucket

Here’s a program from our archives.

ambience, sap dripping
This month, throughout the northeast, farmers are tapping maple trees and processing maple syrup. I’m Jim Metzner and this is the Pulse of the Planet.

We’re listening to the sounds of maple sap dripping into a bucket.

Marvin: Maple syrup is made from the sap of sugar maple trees. Sap is a very dilute sugar solution, perhaps two percent sugar. And it’s cooked down in an evaporator over a wood or oil fire, typically, to a concentration of 67 percent solids, which are mostly sugars with the flavors of maple.

David Marvin runs Butternut Mountain Farm in Johnson, Vermont.

Marvin: The sap is produced during alternative cold nights and warm days in March and April. And it flows from holes that are drilled in the tree seven sixteenths inch i diameter, three inches deep inside the tree. These holes produce sap only until the trees start growing, at which time sap flow stops, usually in mid-April. A single tap hole, or two tap holes in a large tree really are very little harm at all to the tree. We know exactly how much sap is removed from the tree, but perhaps five to ten percent of the stored carbohydrates at most would be removed during a normal sugaring season.
It would be wonderful if we knew what makes sap flow. We don’t know all the answers. Clearly there’s a trigger mechanism based on temperature, but exactly how the tree works is still a mystery. The average tree in an average year will produce about ten gallons of sap, and that produces about one quart of syrup per tap hole.

We’ve been listening to a program from our archives. If you want to hear more, check out our podcast. I’m Jim Metzner and this is the Pulse of the Planet.

A Drop in the Bucket

It's sugaring time in the northeast woods of the US.

Air Date:02/11/2022

Scientist:

Transcript:

A Drop in the Bucket Here's a program from our archives. ambience, sap dripping This month, throughout the northeast, farmers are tapping maple trees and processing maple syrup. I'm Jim Metzner and this is the Pulse of the Planet. We're listening to the sounds of maple sap dripping into a bucket. Marvin: Maple syrup is made from the sap of sugar maple trees. Sap is a very dilute sugar solution, perhaps two percent sugar. And it's cooked down in an evaporator over a wood or oil fire, typically, to a concentration of 67 percent solids, which are mostly sugars with the flavors of maple. David Marvin runs Butternut Mountain Farm in Johnson, Vermont. Marvin: The sap is produced during alternative cold nights and warm days in March and April. And it flows from holes that are drilled in the tree seven sixteenths inch i diameter, three inches deep inside the tree. These holes produce sap only until the trees start growing, at which time sap flow stops, usually in mid-April. A single tap hole, or two tap holes in a large tree really are very little harm at all to the tree. We know exactly how much sap is removed from the tree, but perhaps five to ten percent of the stored carbohydrates at most would be removed during a normal sugaring season. It would be wonderful if we knew what makes sap flow. We don't know all the answers. Clearly there's a trigger mechanism based on temperature, but exactly how the tree works is still a mystery. The average tree in an average year will produce about ten gallons of sap, and that produces about one quart of syrup per tap hole. We've been listening to a program from our archives. If you want to hear more, check out our podcast. I'm Jim Metzner and this is the Pulse of the Planet.