Weather question vs sap run

[Plutoman15]

Hello all,

This is my first year tapping in south central PA. I know the sweet spot is low 20’s at night and 40 during the day. Do you see much run if it is 28 low and 34 high or does it need to get warmer, bigger spread? How soon after the “perfect” swing of temps do you see sap and how long does it run if it fails to go below freezing for a few days.

This is the only chart I can find that shows sap run and temp swings.
81B6ECA4-A6EC-4766-8C93-2BD9BB9AC197.jpg

Thanks everyone,

Joe

[maple flats]

On gravity you generally will not get much if any flow at 34F. On the other end, 28 works but anything 27 or under gets better in my experience. The main thing at this point is that if you have had nearly as much cold as we have, those trees will need time to thaw. Some old timers used to go by the bare ring that develops around a tree, the sap won't flow good until those "donuts" appear. You might get some but it won't flow good yet. Of course that won't work if there is no snow cover to go by.

[DrTimPerkins]

Some old timers used to go by the bare ring that develops around a tree, the sap won't flow good until those "donuts" appear.

Weird fact....the inuit (Eskimo) word for the snow "donut" around the base of trees is qamaniq

You are correct, hard packed snow around the base of trees will keep the truck frozen, and not allow water to flow up and recharge the tree during the "freeze" phase, so no sap flow. Keep in mind that trees are big and full of moisture, so they are fairly highly buffered to changes in air temperature. It is the TREE temperature that is important in sap flow, not the air temperature. That is why trees may not flow even if the air temp gets to 38 deg F (if they've been deeply frozen for days before) or why tree may keep flowing even if the air temp falls to 30 deg F in the night (as long as the tubing doesn't freeze up). Tree temperature doesn't always equal air temperature, there is very frequently a large lag.

[GeneralStark]

Yes the old timers said something about snow around the trees but I have seen my woods run well with lots of snow around the trees....there is no hard fast rule and the same goes with temperature. Clouds vs. sun can have a huge impact... I have seen it run well when the air temp was below freezing but the trees were warmed in the sun...I have also seen it run poorly at 40 degrees under clouds.

This why I have adopted the strategy of just tapping the trees, turning the vac. pump on, not turning it off, and seeing what happens. Trying to remember all the old timer sayings and intuit what may happen just gets tiring.

[DrTimPerkins]

This why I have adopted the strategy of just tapping the trees, turning the vac. pump on, not turning it off, and seeing what happens. Trying to remember all the old timer sayings and intuit what may happen just gets tiring.

Sounds like a good plan to me.

[Evets]

Welcome to the obsession, Joe. I'm here in Lancaster county and I just finished tapping yesterday. Just a small backyard operation with 15 taps. The ones I put in yesterday were all trickling pretty good even though it was only just above freezing. Looking forward to a good run starting today!

[berkshires]

I only have a couple of years under my belt, so take this with a grain of salt, but... For a really good flow you want to see temps in the mid 40s at least, to get it going. Sun helps too. Then as long as it stays above freezing the sap will continue to flow (even overnight). However in my experience if it gets and stays really warm, after a day or two the sugar levels in the sap really drop off.

To recharge the trees, yeah, you need a good freeze. Dr Tim has told us that the slower the freeze, the better the next sap run is. So I think if it just drops in a few hours from above freezing to -20 and is windy, I think no matter how warm the next warmup is, the trees just don't have as much sap stored in the trunk and branches, so you'll have a smaller flow.

Hope that helps!

[Plutoman15]

Thank you everyone, I love the discussion.
I starting keeping bees a few years ago and this hobby feels like it has the same addictive potential.

I am about to go out and check my buckets. i am hoping the 45 degree day got things cranking. I would like to boil tomorrow but need sap. I think yesterday never got warm enough at 34f. Only got a dribble yesterday.

Update: not great. Maybe a pint or 2 from 7 taps. It is deep woods and most are on a north facing slope so maybe they need thawd more. The one was dripping decent.

[Plutoman15]

My trees don’t seem to be flowing well. The ones that get the most sun seem to do better dispit it being
56F today. From 7 taps I got 3/4 gallon of sap. From 2 walnut trees I got 1/2 gallon of sap. The walnuts are almost open trees. The Maples are in the middle of the wood.

So is a quick warm up better than a slow?

[BAP]

What direction is the wind? Is it blowing hard?