To the side of his house, along the edge of the woods, Daniel Killam pours filtered maple sap into metal pans over a custom-made wood stove to boil down the sap.
“I had a very good friend weld this up for me. It's an old fuel oil container that he took the top off and welded a plate down, put a chimney on top,” explained Killam. “I've got this huge wood stove and a good air flow system rolling through it right now. We've got three catering pans on top and a custom-made slot system to hold them above the flame.”
Killam has been adding more trees to his tapping operation each year so it can be a little hard to compare year to year, but so far, the sap has been flowing well this spring.
“We've had these stretches where it'll get nice and warm, the sap will run like crazy. Today's been crazy because it got cold, really cold for a while, and then it warmed back up, and then looks like it will get really cold again, and then it warmed back up. It keeps our season long,” said Killam.
This year, Killam tapped about 40 maples on his and neighbors’ properties. The maple syrup he makes is given out to family and friends.
While the sap flow each spring is heavily weather dependent, the health of the maple tree and forest around it can also significantly impact how much sap a producer can get out of a tree each year.
Something Killam, as a Wisconsin Department of Natural Resources Forester, knows quite well.
“There's some really phenomenal research out there that basically indicates that there's an extremely strong correlation between the crown size of a maple tree, and the amount and the quality of the sap that it produces,” said Killam. “So bigger, bushier crown, more sap.”
For larger commercial operations, forests are managed to get the optimal quality and quantity of sap.
This can include the type of maple tree, sugar maples are most prolific as Killam puts it.
Researchers have found there’s an ideal number of trees per acre and space between each tree.
“As the diameter of the trees goes up, the number of the trees goes down. So bigger trees but fewer means they're more productive,” said Killam. “If you have just a bunch of tiny trees on your land, you're going have a bunch of them to help get started growing. As they get bigger and they mature, you're going to cut them and reduce them down to 64 and maybe the next class will be only 54 trees per acre.”
For folks like Killam that make maple syrup each spring for themselves and family and friends, the purpose of their forest likely isn’t just for making syrup. Maybe they also want good habitat for deer and game birds or they’re planning to harvest the trees in the future.
Implementing changes to increase sap production could be in contradiction to some of these other goals.
“I think it's interesting that you are prioritizing your woods in different ways. It doesn't always have to be either,” said Killam. “You can marry all of your management decisions in different ways.”
For those wanting to make changes to their forest, Killam recommends starting small and focusing on a tree you already know produces well.
“I'll take a look at that, my best producing tree, and I'll say, okay, that oak next to it, maybe it's dead on top and or it's got some something that I don't like about it. I say, ‘Okay, that's a perfect firewood tree for this next year,’” said Killam. “I'll cut it down, open up a whole ‘nother side for the maple tree to start growing and improving, and that hopefully I can get better sap out of it in the future.”
Though don’t expect changes to happen overnight. Killam has seen some of his changes since moving to the property four years ago have an impact, but many may not ever payoff in his lifetime.
“I'm not going to live to see pretty much any of the results, just kind of my own little slice of pie in time,” said Killam. “It extends beyond me. It's like I've made a mark. I've had an impact, and I've had the opportunity to eat some maple syrup along the way. There's something really gratifying about that.”
"My opinion, the best thing that you can go after is what's on your property and what you have access to," said Killam.
The maple sugaring season typically runs sometime between February and April. It ends when the maples start to bud.
For those interested in learning more about forestry and maple sugaring, Killam recommended the following research:
Sugarbush management
Coniferous understory influence
Maple tree stocking
Tapping near old tap holes
There’s also more research through the USFS Northern Research Station.
