In Vermont, maple syrup season starts around the end of February, when the daytime temperatures reach the high-thirties and the night temperatures go below freezing. The season usually lasts until early April, or when you spot wild ramps coming up and spring wild flowers start blooming in the woods.
Maple syrup used to be collected in galvanized buckets hung from metal spiles. Sap dripped into the buckets and slowly filled them, until the sugaring crew came along and emptied the buckets into a horse- or tractor-drawn sap tank. The sap is lightly sweet and clear; nothing like the syrup it gets boiled into. At 2% sugar content in the sap, it takes about 42 gallons of sap to make 1 gallon of syrup.
When we started sugaring, we used buckets and a hobby sized arch under a lean-to. We harvested our own wood and had to carefully watch the boiling pans to make sure the syrup didn't get too hot and scorch the expensive stainless steel.
David built a new sugarhouse on the farm so we could put in a larger arch to boil more sap. We still use only sustainably harvested local wood to fire our arch, most of it coming from dead or culled trees from our sugarbush.
We know that climate change is going to impact the maples. Our sugaring season in Vermont used to start in early March, and many years the first run of sap happens in February now. Our sugarbush, which used to produce sap with 2.5%-3% sugar, now regularly produces sap around 1% sugar. Is this a sign of climate change, a stress response to less predictable weather patterns? Or perhaps a natural cycle of high productivity followed by lower productivity? The sugaring community doesn't fully understand what causes maples to run sweet some years and not on others, although a healthy, unstressed sugarbush seems to correlate with sweeter sap.
We've been able to add some modernizations to help prepare for changes in our sugarbush. Plastic pipeline going to bulk sap collection tanks allows us to collect sap from more trees than we could gather by hand from buckets. (We still use a small number of buckets to collect sap from trees that can't easily be added to pipeline).
Reverse Osmosis removes water from sap, so instead of starting a boil at 1% sugar we can boil sap at 4% sugar. We've never believed in using an RO to bring sap to 10% or higher, as this seems to impact the flavor of the finished maple syrup. Using an RO saves boiling time and decreases the amount of wood it takes to boil sap into syrup.
I'm sure there will be other modern aids in sugaring that come out in the next decade to help sugarers and maples cope with changing weather patterns. In the meantime, we'll focus on a diverse and healthy forest.