New insights into tree biology may be the start of a revolution in the maple syrup industry.
At first, University of Vermont researchers Tim Perkins and Abby van den Berg were just trying to learn more about how sap flows through a maple tree. But what they found eventually blossomed into a new model for syrup production – one where sugarers draw their sap from young trees planted in dense plantations, rather than mature forests.
Perkins and van den Berg were testing a vacuum pump system used to extract sap on a maple tree that had the crown – branches, leaves, and stems – removed. But the vacuum tap kept on pulling sap out long after the researchers expected the flow to stop.
“We got to the point where we should have exhausted any water that was in the tree, but the moisture didn’t drop,” Perkins said in a press release from UVM issued last November. “The only explanation was that we were pulling water out of the ground, right up through and out the stem.”
The discovery led the pair to envision a new method of sugaring. Instead of depending on forest land, a sugarer could use a plantation of young saplings rooted in a farm field.
“Once we saw that we could get yields without tops it was — wow! — this changes the basic paradigm,” van den Berg said in a statement. “It became clear that we could deal with an entirely new framework.”
The plantation model could result in much higher yields, too. The pair estimates that one acre of maple plantation, with 6,000 saplings, could yield 400 gallons of syrup. A traditional “sugarbush” of tapped trees usually yields about 40 gallons of syrup per acre from 80 mature trees.
And efficiency is on the industry’s mind lately. In Nova Scotia, maple syrup trees aren’t yielding up as much sap – a 25 percent drop, on average, from the 1970s, according to the CBC. People are still stumped as to why; climate change is high on the list of potential culprits. Others think the trees may just be overworked from decades of use.
"I think subsequent tapping is slightly detrimental to the tree," Keith Crowe, a 62-year maple industry veteran, told the CBC. "I don't think it's ever as productive as it is in the initial stages in spite of the growth that might happen in the meantime."
Maple syrup production is very subject to the whim of the weather, as sap flow requires cold nights, with below-freezing temperatures, followed by warmer days. Sap also stops flowing in spring when the tree’s flower buds expand and leaves develop. In 2013, U.S. maple syrup producers tapped 3.25 million gallons – a 70 percent increase from 2012, according to the U.S. Department of Agriculture [PDF]. Last year the weather was just right for sap production – cool spring months delayed the maple buds from forming, resulting in a longer season. But who can predict how next years’ season will play out?
The plantation model may also be better suited to cope with a changing climate. The smaller saplings freeze and thaw faster than their grown-up counterparts, so they don't need as intense of a freeze and thaw cycle to start the sap flowing.
Planting saplings for syrup seems like a no-brainer, given the prospect of higher yields on smaller parcels of land – but the costs of equipment, maintenance, and labor are also higher with the plantation method. Still, as Modern Farmer points out, there are other business advantages to a maple plantation -- relying on young trees means that producers could bounce back much faster if their trees are damaged by natural disasters. Instead of waiting decades for a forest to mature, the system devised by the UVM researchers would be up and running within seven years.
Overall, it seems that sugar makers are cautious, but open-minded.
“I could see how it would be very efficient and replace the wild crop,” Hillsboro Sugar Works owner Dave Folino told Modern Farmer. “I’m tied to the old images but it is tantalizing the thought of controlling things. In my lifetime, I’ve seen the shrinking of the dairy industry [in Vermont]. I would hate to see the same for the wild crop but it is probably economically inevitable.”