It seems like ancient history at this point, but only a few weeks ago “false Spring” gave us high hopes with temperatures in the 40s and 50s and lows in the 20s. For many around the region, these temps signaled an exciting moment in the natural cycle of the seasons: The sap would soon be running. By now, those who started assembling their taps, buckets, bags, and cheesecloth feel let down to say the least. John Latimer, KAXE Staff Phenologist and Heidi Holtan, News and Public Affairs Director, chatted with Joel Rosen of Park Lake Farm in Mahtowa, MN last week to get his perspective on what is in store for the syruping season this Spring.
With temps plummeting back below zero for the past week, Rosen thinks that frost depth is the culprit for slowing the sap from flowing. Until the frost starts to come out of the main roots of the trees, there’s no significant flow or even maybe a dry hole,” Rosen said. “I’ve had some reports of places near Lake Superior where sap is starting to flow, maybe a trickle, but those areas have less frost depth than here.”
So what does it take to get the sap flowing? Rosen thinks it’s a “contest between the frost and sun.” For Rosen, the high and low temps don’t need to be in the 50/20 range, but rather the average temperature is what will get the sap pumping. “You’re looking for an average temp right around freezing,” he said. “36 and 24., 50 and 16, it doesn't seem to matter very much to the tree what those diurnal variations are.”
“When will the sap start to flow” is the million-dollar question, and there’s still no telling when sappers will get to fill their buckets this year. “I really can’t say when it will start,” Rosen said. “It’s impossible to predict, but it’s easy to predict once it’s already flowing. Once it starts running it will keep running until you get another [freeze] cycle, and then it shuts down for the night. If it doesn’t get colder at night, it can keep running overnight and surprise you with how much is in your bucket in the morning.”
Sap is running in areas further afield, but the general consensus is that this is a down year for maple syruping. One family near Marine on St. Croix, MN reported that they’ve brought in about one-third of their normal harvest: 2 gallons instead of 6-8 gallons they normally would have collected by this point in the season.
For now, sappers are feeling the ground and hoping for rain before the “fun” starts this Spring. Although the definition of fun is always up for debate. “The gathering I’ve done is seldom what I would call ‘fun,’” Latimer said. “It’s usually, you’re out in the snow, post-holing to the tree in about 18 inches of snow, or you’re in freezing rain. It’s work, sometimes it’s a lot of work,” he said.
“You can make it fun,” responded Rosen. “Well it helps if you plan ahead. Although, I’m not known for that.”
“Not an attribute that I have, either.” said Latimer.
Let us know when your sap is running this Spring. Send your observations and photos to Comments@Kaxe.org, text us at 218-326-1234, or send us a message with your Phenology report to jlatimer@Kaxe.org. Good luck sappers!
