Collecting the Sap.
Maple sugaring "technology" has certainly evolved from buckets hanging on trees. The buckets - while certainly more photogenic - have been replaced with vacuum systems and more sanitary plastic bags.
"Bucket" vs Vacuum
The photo to the right shows a spout used to collect sap with buckets or bags. This is very uncommon today. The first photo at the top of this email shows a more modern vacuum system.
Most maple collection today is done on a vacuum system. There are several advantages:
1) Labor saving. No need to go collect buckets and possibly tear up your woods on a wet day
2) More sap. Read below.
3) Less "infection" to the tree. The tap is essentially an open wound. If using an open tap, there is a chance bacteria could get into the tree, causing the hole to scar over and requiring the operator to drill more holes.
The vacuum system does require that you have a stand of trees close together for collecting. If you have one tree in your lawn, a few around the road, etc, then the bags make more sense.
Around here, generally the guys on vacuum tap a maximum of about 300 trees per vacuum line. An 18 inch hard maple can support 2 taps on the same plane. A general rule of thumb is to look for a big root and go above that on each side of the tree. Those big roots are major arteries for the sap.
One neighbor recently wanted proof. He tapped a few remote trees with bags and the rest with a vacuum system. He collected an average of 11 gallons of sap per tap with the bags (bucket method). With the vacuum method, he averaged 28 gallons of sap. Both saps were considered equal in density and sugar content.
What weather conditions create sap? It's simple. Freezing nights and days above freezing, particularly sunny days. If the temperature stays above freezing for about 5 days, the season tends to end. Once the trees start to bud, the season is definitely over.
Which Trees to Tap and Where?
There is a difference in where the tree is located for how much sap it produces. A big maple out in the open with a big canopy will produce more maple sap than a tree in the forest. It can collect more sun.
Trees also on the north side of a hill will also tend to run longer. And if a tree is tapped on both the north and south side of the tree, the southern tap produces more sap early and the northern tap produces more sap later. It's logical. Early on, the southern tap has more exposure to sun. That side of the tree starts to run sooner and produces more sap than the northern tap. Later in the season, the southern side of the tree will have run its course before the northern side is done.
In terms of how many trees you can find in a good "sugarbush," generally 20 to 30 trees per acre is considered good. If you have 300 trees tapped, its usually a sugarbush of about 10 to 15 acres of woods. If we do a little math, 20 trees per acre, 28 gallons of sap per tree, and approximately a 50:1 conversion of sap to syrup....an acre might produce 10 gallons of syrup with a wholesale value of $40 per gallon - so about $400 per acre.
Does this harm the tree? No, a maple tree will not die from being tapped for sap. The major concern about tapping is scars that it will leave in the wood if the tree is harvested for lumber. Lumber buyers want trees that have not been tapped as they don't want the scars in the wood grain.
What makes the sap dark vs light? Mother nature. Generally the earlier sap is lighter in color and the later sap darker. The darker sap has more maple flavor and is today more prized by consumers