High-density sugar maples for syrup
While
scanning the hillside for other sugar maples along my usual morning
walk, Mark and I discussed the possibility of planting some new maples
for tapping later in our lives. The hillside I walk past daily is a
perfect location for sugar maples --- a damp, north-facing spot --- and I
suspect the only reason sugar maples aren't currently in residence is
because the area was logged too recently for this semi-old-growth
species to thrive in the young woods.
But when I got home and
did some research, I discovered that planted sugar maples won't be ready
to tap for at least forty years. I consider myself a long-term
thinker...but that's really long term (especially given current climate
fluctuations and our location at the southern extreme of the sugar
maple's range). Instead, I started wondering whether the intriguing
experiments carried out at the Proctor Maple Research Center
might not be a better avenue to explore. The scientists in charge have
been experimenting with a high-density, pollarded maple operation and
have found that you can harvest up to ten times as much sap per acre
using high-density trees, with the initial harvest only seven years
after planting. Now that sounds like something I'd like to try!
The
big negative about this high-density maple system from a backyard
standpoint is that you have to use a vacuum system to get the sap out of
the trees. Timothy Perkins of the Proctor Maple Research Center kindly
wrote back to me within hours with answers to my numerous questions, and
he noted: "Vacuum is REQUIRED. You will get almost no sap without it.
In addition, the 'sap caps' are not commercially available. We are
working with maple equipment manufacturers now, and expect there will be
a product available for the 2017 sap season." I'm not too worried about
the lack of commercial sap caps --- it looks like something we can
easily cobble together --- and Mark suspects that we could also come up
with a backyard-style vacuum system using a breast pump (like we'll be
using on our goats) or a shop vac. Plus, I don't have to figure that out
until 2022, so why not go ahead and plant now?
Unfortunately, the system
is very new, so Perkins had less concrete answers for my other
questions. When asked how close together the trees should be planted,
Perkins said that his experiments utilized an already-existing nursery,
and thus he doesn't have solid data on optimal spacing. However, one
news article suggested a trees-per-acre density that would come down to
one sugar maple every three feet, which seems like a good start. In
terms of frequency of harvest, Perkins said that after the first seven
years of growth "you can harvest for several years prior to letting the
saplings 'rest.'" (And, keep in mind that like with other pollarding
systems, you'd also get firewood for energy and leaves for mulch out of
the planting.)
So will we be planting
high-density sugar maples this winter? I suspect Mark will talk me into
setting aside at least one experimental row, but first I need to do some
more research. "It would be best to plant high-sap sugar-content
saplings," Perkins recommended...so now I need to do a bit more research
and track down a source.
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About us: Anna Hess and Mark Hamilton spent over a decade living self-sufficiently in the mountains of Virginia before moving north to start over from scratch in the foothills of Ohio. They've experimented with permaculture, no-till gardening, trailersteading, home-based microbusinesses and much more, writing about their adventures in both blogs and books.
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First, I will cut back on my own use of sweeteners! Second, I resist technology to this extent, when we know that the ash-borer is also zooming in on maple trees. To set up research is good. But maple products, syrup and sugar, are rare for a purpose: not everything should be mass-produced! There are other sweet-sap trees, too: birch, for one. I do know that, with climate change, soon the rise of sap will be less dependable, unless in more northern zones.
The old-time way, using horses, was right for the environment. This new way will depend on an energy source to pump the sap. So, I am opposed.
Mom --- I had an inkling you'd feel that way! And, on the one hand I agree with you. I suspect that there are lots of tracts of mature forest in New England that are protected solely because they act as a sugar bush and bring their owners income. I'd hate to see a different system put that situation into doubt.
On the other hand, with the cat out of the bag, I'd say this could be a very sustainable method of producing new areas for sweetener production. From a sustainability standpoint, this method definitely beats cane sugar and is probably better than conventionally-raised honey too (no chemicals). For a small backyard hobbyist, it might be your only option if you don't want to wait 40 years for a new tree to be ready to tap.
About the energy-source through pumping --- I'm afraid nearly all medium-to-large-scale operations now use the vacuum system. And I feel like if we put our minds to it, there should be a way to use gravity in this system on a backyard scale....
From the looks of the bags on top of the saplings, they're using a substantial amount of vacuum. Probably more than you would be able get from a breastfeeding pump. And given the long hoses and lots of connectors, you'll need a pump that can cope with a significant amount of leakage.
For vacuum infusion of composites, we use oil-libricated rotary vane pumps that have a capacity of 25 normal m3/hour, and can get as low as 20 mbar absolute pressure. When doing resin infusion under a vacuum bag, our bags look like the bags on top of the saplings.
Keep in mind that a vacuum pump needs a significant amount of power. From say 100 W for a 4 m³/h model to 750 W for a 25 m³/h model. They can be quite noisy, especially if not well maintained.
While it's true that the average age of a true sugar maple (acer saccharum) when it crosses the 10" trunk diameter threshold is between 30 and 40 years, they aren't the only maples that will give you syrup! Some species, like Silver Maple and certain fast growing cultivars, can hit that point in just 10-12 years.
These other varieties often don't have quite such a high sugar concentration, but if you've got a decent number of them, you can definitely start to tuck away a couple gallons of delicious each year, in less than 15 years.