Tapping High

[Wanabe1972]

What are your feelings on tapping a tree high. I have a dozen nice size maples in my bush that are lower than my main line due to the lay of the land. I have never tapped these because the taps would be 6 feet or so high to get into a saddle T. I've been watching some videos online and see people tapping with a step ladder to get into the main lines. Would it be worth it to do this for another 20 taps. I've heard if you tap high you get more sap but a much lower sugar content. These trees are all hard maples.

[KenWP]

Don't let Theron here you might pass up more sap. Go for it. The extra 20 gallons a day of sap will add up over the season.

[Dave Y]

Wives tales! I have some just like you discribed. Sap is sap and taps are taps. Do what you need to, to get both!

[Dill]

I have a friend that taps his whole sugar bush on between 15 and 25 ft off the ground.

[red maples]

I have a few trees that will be 10+ feet at tap hieght. everthing I have read says height doesn't matter. (just look at wes welker and dustin pedroia) sap flows to the entire tree.

[Toblerone]

I've been wondering this very question. Thanks for asking it.

[peacemaker]

i dont suggest doing anything high ...........maybe one thing

[Amber Gold]

If you can get vac. hooked up, tap them at normal height and the vacuum will suck the sap into the high mainline.

[PerryW]

I had a few trees that I tapped using a ladder (about 10 feet high) and they ran great. Can't see how the sugar content could be any different just because the hole is higher up the tree. It's the same sap that flows up the tree through capillary action.

[DrTimPerkins]

I've heard if you tap high you get more sap but a much lower sugar content. These trees are all hard maples.

Sugar content varies so much that I don't think there's been any good relationship established with height.

If you're tapping with gravity tubing, lower is better. Most of the pressure that causes sap exudation (with gravity tubing) comes from.....gravity, and the sap flows from above the taphole down. So the lower the taphole, the higher your pressure, the more sap. Think of it as a big pipe in the ground filled with water. If you tap higher up on the pipe, water will come out, but it'll stop faster. If you tap low down, it'll run really fast (higher pressure) and you'll get more sap. All that said....it is still important to not cluster tap and kill an area of wood low on the stem. That would be bad.

On vacuum tubing, that difference disappears. Sap comes from all around the taphole, and from a much larger area in the tree, so the difference due to height is negligible.

[Toblerone]

Most of the pressure that causes sap exudation (with gravity tubing) comes from.....gravity, and the sap flows from above the taphole down.

What is the other source of pressure? One year we had a big ice storm that really damaged the crown of some of our big maples and during taping, sap was raining on me from the very top of the tree. I understand the tree, necessarily has to get sap to every part of the tree, and then back down to the roots. I am just curious about the relative difference. And when we tap and get a run does that mean that we are getting the sap on the downward flow?

Also if on gravity tubing, then, taping below the mainline doesn't help any as the pressure at the mainline ought to be the same as if you had tapped at mainline level. In other words if by necessity my mainline is 10ft high at the upper end tree, it shouldn't really matter at what height I tap that last tree as long as it's not above the mainline? Does that make sense?

[DrTimPerkins]

What is the other source of pressure? <snip>...when we tap and get a run does that mean that we are getting the sap on the downward flow?

The primary other source of pressure is due to expansion of gas bubbles in the lumen space of wood fibers. This is a lesser component than gravity. Perhaps also some osmotic pressure, but this is still debated by scientists.

Yes, under GRAVITY flow conditions during the exudation phase, the bulk flow of sap is downward.

If there are intact branches anywhere on the tree ABOVE the broken branches, sap will come out the broken branches. For example....fill a drum with water and attach several hoses to it. Poke a hole in one hose and water will run out as long as there is any pressure (head) of water above the height of the leak. Doesn't much matte where the leak is....it matters that there is a connection and that there is a pressure head.


if by necessity my mainline is 10ft high at the upper end tree, it shouldn't really matter at what height I tap that last tree as long as it's not above the mainline? Does that make sense?

Sorry, I do not believe I understand your question. If I am understanding it correctly....then (sorry) what you say doesn't make sense. Pressure is pressure. In this case (especially at the beginning of the flow period) it derives mainly from the height of the tree. It is relative to where you measure it (unless you're using an absolute gauge...which nobody in the maple industry does). Two examples....a balloon...pressure is everywhere in the contained area. Poke a hole, and the air will come out until the pressure inside is the same as the outside. This is NOT how a tree works (under gravity). Think of it more as a pipe stuck in the ground, filled with water. A hole drilled in the pipe will result in sap coming out. Drill it higher, less sap will come out. Drill it lower, more will come out. But if you drill it low and connect tubing to it going up, sap will still come out, until the pressure falls to match the height of the top end of the tubing.

[Toblerone]

But if you drill it low and connect tubing to it going up, sap will still come out, until the pressure falls to match the height of the top end of the tubing.

This answers my question exactly. Sorry I was not clear. In other words, if my tubing is connected to a mainline that is at 10ft above the ground, the sap pressure there (at the mainline connection) will be similar to that of a tap in the tree at 10ft above the ground... regardless of where the tap actually is in the tree.

Thanks,
Dave

[DrTimPerkins]

if my tubing is connected to a mainline that is at 10ft above the ground, the sap pressure there (at the mainline connection) will be similar to that of a tap in the tree at 10ft above the ground... regardless of where the tap actually is in the tree.

Yes. Correct. However keep in mind that if the sap has to run uphill, it will ferment in the line and will be drawn back into the taphole very readily during the freeze cycles. This will cause the taphole to dry out very quickly.

[Toblerone]

Ah! Thank you! It looks like I need to either bring a ladder with me or buy some spouts with the check valve! Would those work in this uphill dropline scenario?

[DrTimPerkins]

Ah! Thank you! It looks like I need to either bring a ladder with me or buy some spouts with the check valve! Would those work in this uphill dropline scenario?

They may help to keep the sap that's come out from going back into the taphole, but they won't slow fermentation in the line. Since the taphole is going to be filled with sap, they may ferment fairly quickly even with the CV adapter. Tapping below the mainline is probably not the best idea. Better to tap higher than the mainline if possible.