A new method of harvesting sap from young trees could revolutionize maple syrup production in Vermont — and potentially around the world.
Researchers at the University of Vermont’s Proctor Maple Research Center have discovered that sugar maple saplings produce the same sweet liquid that mature trees yield.
Sugar maple saplings can out-produce mature trees by an order of magnitude. A plantation-style crop of 6,000 saplings can produce 400 gallons of syrup per acre, while a mature sugarbush of 80 mature maple trees produces 40 gallons per acre, researchers say.
Saplings are ready to harvest in seven years, while mature trees take four decades to tap.
The implications could be significant for one of Vermont’s signature products — as a hedge against climate change, as a relatively cheap and fast way to grow a maple operation and as an opportunity for competitors to get a foothold in the market.
Tim Perkins, Proctor Center director and one of the lead researchers who made the discovery, said the plantation method is not a replacement for traditional maple sugaring. He described the innovation as a complement to sugarbush production — in much the same way tube and vacuum technology recently transformed the industry.
Matt Gordon, the executive director of the Vermont Maple Sugar Makers Association, is reserving judgment about what the technology will mean for producers in the state.
“Everything about it is so new and so cutting edge, it just sounds like really interesting experiments,” Gordon said. “No one’s going to give up their old sugarbush with mature trees.”
Innovation’s threats, opportunities
Perkins said the sapling method might be most valuable to maple producers who have limited space or want to expand their operations quickly.
Sapling plantations could help sugarmakers recover more quickly from a devastating storm or pest infestation, for example.
Plantations also would give producers more control over growing conditions — potentially crucial in the face of anticipated climate change.
As the Proctor Center continues its research, Gordon said he will be most interested in what the developments mean for maple operations that struggle with the high cost of sugar maple forestland.
The plantation method allows for dense planting of saplings in an open field, and the critical feature that makes sugarbush land so valuable — a mature maple forest — becomes moot.
But that’s not to say maple saplings could be raised plantation-style anywhere, Perkins cautioned. The freeze-thaw cycle that turns starch into sugar is still needed to produce sweetness, he said. “But smaller trees freeze and thaw much faster,” he said.
Still, Perkins said, “You’re not going to see maple syrup being made in Florida. It’s going to be northern climates.” Nor does the thought of growing maple saplings in greenhouses sound to him like a lucrative prospect.
And due to the Northeast’s longstanding specialty in maple sugaring — from equipment manufacturing and repair to expertise in plant biology — Perkins thinks the maple brand will not escape the region any time soon.
“At least in the short-term, it’s unlikely that someone else will jump in and make maple syrup more economically than we can in New England,” he said.
Meanwhile, the University of Vermont is already doing what it can to maintain the state’s grip on the maple technology and brand. The school applied for a patent in 2012 for the vacuum process and all devices associated with plantation-style sapling production. That includes the contraptions Perkins and his colleague, Abby van den Berg, improvised to fit standard tubing to sapling tops.
The application was published in September 2013, at which time the researchers could finally go public with what they had been studying since spring 2010.
How it works, how it tastes
In the course of studying maple sap production, Perkins said, he and van den Berg realized that the sap they were collecting was being produced from tree roots — not from the tops of the trees, as had traditionally been assumed.
This was not an entirely accidental discovery. The scientists began studying sap production under different types of “flow conditions” — for example, in gravity versus vacuum collection systems. Partway through the season, Perkins said, it occurred to them to test the idea that sap was being produced from water being pulled up through the roots.
What they found reinforced the theory.
“The main thing was that, after a long thaw, sap flow didn’t stop.” Perkins said. The top of the sapling had already been cut off, so they knew the sap being pulled out by a vacuum was coming from below.
“But even with that, if you were only drawing from the tree itself, the moisture content would drop off,” Perkins said. “The only place it could be coming from was from water in the soil.”
This could mean that plantation-style production would be water-intensive, he said. But Perkins dismissed that as a problem in the Northeast climate, given spring snowmelt. If maple plantations were to require irrigation, he suggested, producers are already accustomed to working with tubing, so the new application would not be a stretch.
Trees survive the plantation method, but must be managed carefully to continue production without interruption from season to season. After sap production, the vacuum apparatus is removed from the top of the stem, at which point the tree regrows a compact, bushy crown, Perkins said. The following year, about 6 to 12 inches must be cut off again to freshen the top — attrition that growth can’t make up for. Eventually the tree would be trimmed to the ground.
Instead of resting the sapling for a few seasons to regenerate, Perkins said alternate methods of coppicing or pollarding keep the sap active.
The coppice method involves cutting the sapling close to the ground early, and letting it form multiple stems. A producer could alternate the harvest from one stem to another year after year, allowing sufficient growth on each stem before it’s decrowned again.
Pollarding allows the tree to grow 4 to 5 feet off the ground. This has distinct advantages in the Northeast, Perkins pointed out, because at that height deer cannot nibble the tops of the trees.
Perkins said in all cases, the chemistry of the sap is identical to that produced by mature maples. The taste is the same, too, he said — though he confessed he hadn’t yet tried it on pancakes.
“Our value in a sense is the science and not the syrup,” Perkins said.
While maple syrup from wherever it originates might be chemically identical, it also differs slightly in taste, as another UVM research is keen to point out.
In the Nutrition and Food Science department, Dr. Amy Trubek is extending a theory of a “taste of place” from wine to maple syrup. Trubek is refining a matrix of flavors — toasted, milky and fruity to name a few — that can be traced to environmental conditions such as soil conditions or the bedrock over which maple trees grow.
Gordon said he would not expect the syrup made from saplings to taste like anything other than maple.
“It’s the same product,” Gordon said. “It’s still just the sap from the maple tree that was boiled down and evaporated to make maple syrup.” Only the collection method is changing, and the industry has already weathered a lot of change, he and Perkins are quick to underscore — despite its traditional brand image.
“It’s definitely something very different,” Gordon said. “But tubing looks different than buckets. Most people don’t use horses to collect their sap anymore. Not everyone wears plaid in the forest.”
Before he’s ready to get either excited or worried about what the sapling “plantation” method could mean for Vermont producers, Gordon is more focused on products that lay false claim to maple’s cachet. He said the more popular maple syrup gets, the more shelves are stuffed with food items that claim maple flavoring without a bit of syrup in their ingredients.
Gordon said his organization wants to change consumer preferences and hopefully food manufacturing protocols to demand real maple syrup if a maple leaf and bottle will appear on a label.
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