Best temps for sap flow

[saphound]

Ok you veteran tappers..what do you consider the most ideal hi's and lows for sap flow. I know you want below freezing at night and above during the day, but that could include quite a large range of temperatures. I'm looking at the next weeks forecast and it's up and down from 22/35F to 35/55F and everything in between. Is a low of 22 better than a low of 30? a high of 55 better than 40? Just wondering what to expect and try to plan my week accordingly, thanks.

[n8hutch]

Once the trees have thawed 20-45 I think is Ideal,
When you start to get those real warm days your sap gets warmer & your trees are going to bud that much faster

[groomer_guy]

The past two days it has been 18/19 at night and 36 degrees during the day here in Savoy MA. at 2150' elevation. The sap is starting to run ok. Today it should run good. It was 20 degrees this morning and it is supposed to be around 45 degrees today so I think it will be a good sap day.

[John c]

Mother Nature is awfully fickle. Some of my best runs have been on days that I never thought it would run at all! Just this year my best run was on a 34 degree, snowy, and windy day and the buckets filled up twice instead of once with 3%.

[Biz]

20 degrees or colder is too cold for an ideal run, the trees will not thaw out and start running until about noon, other than ones in direct morning sun. I think the ideal temp is 25-29 degrees at night, 38-45 in the daytime. Needs to be cold enough for long enough at night to freeze, but not too cold, and around 40 during the day to thaw quick enough to start running by about 9AM. If it hits the teens at night, it will take till noon to start running. If too warm during the day like 50, it might not freeze well enough at night.

This is for buckets, vacuum may be playing by a different set of rules.

Dave
Looking forward to 12 hrs of boiling today! And maybe tomorrow too.

[beaglebriar]

Mother Nature is awfully fickle. Some of my best runs have been on days that I never thought it would run at all! Just this year my best run was on a 34 degree, snowy, and windy day and the buckets filled up twice instead of once with 3%.

This is what I've seen as well. Can't say for sure what my sugar content is though. Hope its 3%!

[saphound]

That's interesting John c. My trees deeper in the woods haven't been doing a whole lot since it turned colder here. Two weeks ago it hit 50 a few days and they ran pretty good. I have one tree on the edge of the yard that gets full sun and it'd been putting out 2-3 gals a day. Lucky to get that from the other 9 combined. Wish I had more like that one. Supposed to go to about 60 here today, after a low of 25.. that should wake things up. In 3 days it's supposed to go back to the 30's for a few. I'll be boiling the 25 gals I have today to make room in case somethin big happens. Thanks for the input y'all.

[WESTVIRGINIAMAPLER]

I like 25 at night and 40 to 45 days.

[PerryW]

early in the season you need much warmer daytime temps to get things flowing. Later in the season you need much colder temps at night to recharge the trees. But in the middle of the season I hope for 20 at night and 40 during the day with full sun and no wind.

[DrTimPerkins]

The factor determining whether sap flows is the BRANCH and STEM temperature, not air temperature. However not a lot of people actually measure wood temperature, so air temperature is used as a surrogate, but that means there is much variability. When the wood just reaches below freezing, and then quickly rises above freezing in the following day we get the best sap flows. A nice SLOW freeze is the best for recharge, but it needn't get really cold. A nice slow freeze where the low temperature just achieves complete freezing of the wood is best, because then just a slight rise in temperature the next morning will get things started quickly for the day. Interestingly, the whole tree is not one big isothermal entity. Different parts of it might be thawed or frozen, so one side (typically south) can run on a sunny day or early in the spring, while the other side (north) will start running later, and keep running longer in the year.

[saphound]

Thanks for that great information Dr. Tim ..and Perry too! Sounds like the next few days should be real good. :cool:

[michiganphil]

The freeze/thaw cycle is critical to sap flow, but it's not as simple as cold nights and warm days. If the sun goes down and the temp drops quickly instantly freezing things up, the sap flow the next day will generally be marginal.

Dr. Tim touched on probably the most important factor: a long gradual cool-down to just below freezing is more important than quickly freezing.

[crazyjackcsa]

My trees are all out in the open. I like to see the lows around 25 and the highs around 40 like other people have pointed out. If it's sunny, I can get flow down around 30 or 28 on a calm day. I'm coming to the end of my season right now and praying for a couple of cool nights to get a little more sap.

[smokeyamber]

So if the tree is on a southern slope and large enough for two taps the optimum is to put on on the south side and one on the north side , and if in doubt put the tap on the colder side for a longer running tap flow ? That would change my current process of using mostly the south side on my hillside location.

[DrTimPerkins]

So if the tree is on a southern slope and large enough for two taps the optimum is to put on on the south side and one on the north side , and if in doubt put the tap on the colder side for a longer running tap flow ? That would change my current process of using mostly the south side on my hillside location.

Over time you should just utilize the full tapping band in order to reduce the changes of hitting stained (non-functional) wood. If you tap on the north side, you will typically get later sap flows. If you tap on the south side, you'll generally get earlier sap flows. Best approach is to tap all around the entire circumference of the tree over a period of time. This avoids the cluster-tapping effect. Several studies have shown that on average you will get the same amount of sap from any side, regardless of aspect. Some years might be better on the north, some on the south, but it isn't possible to predict which way to go before the season starts. By tapping all around different sides on different trees, you even out the odds to a large degree.

[saphound]

Dr. Tim, After several years of going around a tree, can you eventually create enough non-functional wood that sap can't flow and the tree dies?

[TerryEspo]

Well Tim, you made me go to the back and check my lines. You said the temp of the branch is more important than air temp, so I went to the back. Sure enough, sap in lines, windy here, cool, just at freezing, not above, not below, 0C, 32F.

I am getting sap, not much ,but some.

Due to the sun being out I feel the branches are above freezing. I just wish the high winds would stop and it would be a nice day here.

I maybe will get 10-15 gallons from my 50 taps today, as a guess from what I saw flowing into the collection barrel. Tomorrow is a better day, a few degrees above freezing, less windy and sunny, below 0C, 32F, later tonight also.

I will remember wood temp is more important that air temp.

Thanks.

Terry

[DrTimPerkins]

Dr. Tim, After several years of going around a tree, can you eventually create enough non-functional wood that sap can't flow and the tree dies?

No, the pipes in the tree (vessel elements) are short, and don't line up precisely all the time, so there is some lateral flow. It is more like a jumble of pipes all dropped down into an area that basically run up/down. So tapping around the tree will create zones of stained, non-conductive wood, but more will be growing on the outside of those old taphole stains, and there is some above and below that zone, so you're OK.....as long as you don't do so many that you do start to build up very high levels of non-conductive wood. That is why we have sustainable tapping guidelines.

[DaveB]

This thread is interesting to me as a meteorologist and one who records daily temperatures. I'm wondering what kind of sensors you use to measure the stem/wood temperature and if there are any graphs showing ideal temperature traces or if you can even predict what the flow will be like based on that.

[TerryEspo]

In all honesty my sensor is puddles of water. First thing in a .m., they have ice on top, if the sun can melt that ice even when its below freezing, it can melt the ice in my lines and warm the tree branches.

Worked today for me, not for long though, but got some sap.

Terry

[Farmer Jim]

Does rising/falling barometric pressure play a role?

[n8hutch]

Sure seems like it does.

[poulin]

Hi all,

And what do you think happens when we hit a 4-5 non freezing days in the season ? Does the run stop for that period and resume when the freeze/thaw cycle starts back ?

It is non even really begun here and that's what is forecasted after this week. Have those non freezing nights the same impact in the beginning of the season than at the end of it ?

Thanks all

A happy beginner

[saphound]

Wondering about that too, Poulin. Tonight low of 30, then 7 days of above freezing. :( Never thought I'd be mad about that! I was just gettin goin...

[Locust Farms]

Records from Southern Indiana. Season really over here. attach jpg of jan feb mar apr records. sugar maple records reds quit 16 mar ,sugar 1 april

Dwight115821158311584

[DrTimPerkins]

In all honesty my sensor is puddles of water. First thing in a .m., they have ice on top, if the sun can melt that ice even when its below freezing, it can melt the ice in my lines and warm the tree branches.

If our gravel driveway has frozen solid, then the trees had a good freeze. Only surface frost and puddles frozen means a light freeze, but not a full recharge. Still mushy roads, no freeze.