What weather will end the sap run?

[johnpjackson]

Here in Western Mass we had a great sap run on Wednesday and Thursday. But the last two nights were well above freezing and the run has pretty much stopped. The forecast for the next several days looks much better for sap running - below freezing nights and warm days. My question is, might the sap start running again though, now that the past couple of warm nights seemed to have stopped it? Does that stop it for the season, or will the sap start running again?

-John

[tcross]

it'll start running again! once you get another freeze/thaw cycle, the trees will start producing. they'll do this basically until there are leaves on the trees, however once the trees bud out, the sap turns sour and your season is done.

[DrTimPerkins]

Here in Western Mass we had a great sap run on Wednesday and Thursday. But the last two nights were well above freezing and the run has pretty much stopped. The forecast for the next several days looks much better for sap running - below freezing nights and warm days. My question is, might the sap start running again though, now that the past couple of warm nights seemed to have stopped it? Does that stop it for the season, or will the sap start running again?

-John

Easiest way to think about it is as if the tree is a balloon. A freeze will blow up (inflate) the balloon (pull sap up into the tree). A thaw will let let the air (sap) out. After a while all the air is out of the balloon until it is inflated again. A tree on gravity sap collection will run for a few days...maybe a bit more depending on the weather, but then needs a freeze to recharge the system.

[berkshires]

Easiest way to think about it is as if the tree is a balloon. A freeze will blow up (inflate) the balloon (pull sap up into the tree). A thaw will let let the air (sap) out. After a while all the air is out of the balloon until it is inflated again. A tree on gravity sap collection will run for a few days...maybe a bit more depending on the weather, but then needs a freeze to recharge the system.

The other piece of it is your taphole. Think of the taphole as a little pinhole in the balloon. When the balloon inflates, some of what's in the balloon comes out your taphole, and when it deflates, the flow stops. But that pinhole has a limited time it stays open before the tree closes it off. A lot of factors go into the question of how long it stays open. These include:

- What you have plugged into your tapholes: A tubing system with all new fittings can, some say, keep up with good runs for three months or more. On the other extreme, taps directly into buckets will probably begin to heal/slow down around four weeks out, and for the next month will continue to produce less and less.

- Sanitation: The reason there's so much difference in the above is that spiles into buckets are completely open to the air, so all the microbes can go right into the holes, causing the tree to react and start the process of closing them. You can accelerate the process of the tree closing up if your fittings, taps, or holes, are dirty.

- Weather: Cold suppresses the growth of the microbes that the tree responds to, so when it's cold, it will take longer for the tree to heal than when it's warm. In some cases a few really warm days might accelerate the shut down your tree early because of an explosive growth in the microbes.

I'm sure Dr Tim could explain it much better than me, but hopefully I haven't screwed it up too much, and the above is close enough for us backyarders to muddle along.

Cheers,

Gabe

[DrTimPerkins]

I'm sure Dr Tim could explain it much better than me, but hopefully I haven't screwed it up too much, and the above is close enough for us backyarders to muddle along.

No need to explain further....you got it.