I was wondering if you could reduce the syrup by freeze concentration, like apple jack. Turns out the flavor is developed by cooking, according to this 1950 publication.
BUT--I suspect it isn't an either/or proposition. Reduce the water volume by freezing (which should be free in sapping season!) and then do the final cooking that gives it molecular character. With plenty of sticks lying about from the coppicing to vacuum out the sap, this sounds like an easy job for a rocket stove.
Let's see, 400 gal of syrup, farmers market $40 gal...$16K per acre...less marketing, packaging and labor costs...now stack some other stuff on that...a decent income stream on fallow land for sure.
On a much smaller scale, if a homestead only wanted 10-20 gallons of syrup a year that would be 150 to 300 trees (bushes?). Spread that over an acre and it leaves plenty of sunshine and room for other annuals.
Anyone want to be the first to try this with box elder? Maple grows painfully slow here in Utah, but box elder doesn't seem to suffer from the altitude and climate. (I wonder if tapping the sap would reduce the number of box elder bugs. I know -- fat chance. I can always hope, though.)
Investment in reverse osmosis would be a requirement to making it somewhat economical, I am guessing.
Does mountain maple produce a sweet sap?
Location: Torrey, UT; 6,840'/2085m; 7.5" precip; 125 frost-free days