Tapping higher off the ground

[drpausch]

I plan on trying 3/16 tubing this year, but wondering if there is any info on how high in the tree you can tap to get best results? Here is the situation, I have good elevation (30") but have trees near the bottom of the slope and thinking of tapping them higher to get more elevation drop to the discharge of the tubing. How high can I tap with no loss of production?

[Bentley Wood Maple]

Have about 40 taps on end of one line we tap standing on rear rack of wheeler while parked on couple feet of snow. Need to be about 8-10 ft in air to get enough drop. We tap a few trees from tailgate of pickup so line can cross driveway.
Biggest issue I have is pulling taps after snow goes away.

[Maplesapper]

I wonder if there are long term issues with the staining that occurs in the wood above the tap hole if you tap it higher on the trunk?
Maybe if you tap the same tree's in the higher location year after year its ok?

We install some high while wearing snowshoes and occasionally need a ladder to undo them.
Only challenge we have with high taps- is repairing leaks- and having to drag a ladder back out in the snow.

[maplekids]

The old poem
The higher the tap
The more the sap
The lower the tap
The sweeter the sap
Tap were it works the best for you

[pennslytucky]

i was wondering this too. my daughters treehouse is about 10 feet up in a big suger maple. the kids will eventually tear up the lines if its below the treehouse. what would be the difference between the sap at 15-20' and 4'? has there been a study on this? id also like tp run lines throughout the pasture trees, but they would have to be 10' up for obvious reasons

[ennismaple]

I believe Dr Tim and others have responded to this question in the past so I'll give it a go based on my understanding of their response. Under gravity flow, the lower you tap the more sap you will get. The tree acts as a "straw" that is filled with water (sap). If you poke a small hole in the bottom of the straw the entire volume of water is available to flow out through the hole. If you poke a hole in the straw midway up half the volume is not available to flow out of the hole.

Unless you have to tap high, keep it down at waist to chest height.

[DrTimPerkins]

The higher the tap
The more the sap
The lower the tap
The sweeter the sap

Nice poem, but probably wrong. Typically sap is sweeter higher in the stem, but more volume from lower in the stem.

[CampHamp]

I don't believe the straw analogy applies perfectly to cases where you are sucking sap up from below the tap hole (vac and 3/16). If you used a 10-foot drop line of 3/16" tube on those bottom trees would you accomplish the same benefit/loss as running your lateral that high? Will the increase in vacuum gained by an increase in tap height ever make up for the sap not taken from below its reach? One clear benefit: you'll be far less likely of hitting dead wood from an old tap hole!

[DrTimPerkins]

I don't believe the straw analogy applies perfectly to cases where you are sucking sap up from below the tap hole (vac and 3/16).

Several possible scenarios in play here.

Gravity sap collection without a pump or natural vacuum - tapping higher up will reduce the head pressure

Gravity sap collection without a pump, but with 3/16" natural vacuum - tapping higher results in a slight loss of head pressure, but natural vacuum offsets this loss a varying degree depending upon how far your drop is from the taphole to the outlet of the lateral line. Result is considerably more sap due to the contribution of vacuum, but a minute less from tapping at a standard height.

Vacuum sap collection with a pump - same as above.

In essence, anytime you have to "suck" sap upward, there will be some loss of the pressure potential component of the equation. It can range from moderate to small depending on the method and heights involved. However you can never gain quite as much from tapping higher on the stem to get "natural vacuum" than you will lose in head pressure due to the laws of physics.


One clear benefit: you'll be far less likely of hitting dead wood from an old tap hole!

That is absolutely correct. If you are encountering stained wood from an old taphole, there are several possible approaches to solving the problem. One would be to reduce the tapping intensity using shallower tapholes, smaller tapholes, fewer tapholes. Another would be to increase the size of the tapping band (tap higher or lower on the stem, perhaps by increasing dropline length), or encourage faster tree growth (thinning or fertilization -- if indicated). UVM PMRC and UVM Maple Extension are looking at tapping below the lateral line (with both 5/16" and 3/16" tubing) during the 2015 season as an approach to increase the size of the tapping band. At least some of this work was funded by the North American Maple Research Council via the "Penny per Container" voluntary contribution producers can choose to make when buying jugs.

[Leadft]

I have some taps that are quite high at the end of gravity laterals....
I wondered what effect the height might have on production....

[Russell Lampron]

I use a vacuum pump and because of the lay of the land some of my taps are as high as I can reach without a ladder. I get more sap this way than by tapping so that the tap is actually lower than the mainline. The vacuum will pull the sap up the lateral but the vacuum at the end tap is low to non existent.

[maplestudent]

Maplesapper:

"We install some high while wearing snowshoes and occasionally need a ladder to undo them.
Only challenge we have with high taps- is repairing leaks- and having to drag a ladder back out in the snow."

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I've had the same problem. Last year I built an 8' ladder using three 2x4's (not pressure treated - to reduce weight) and just left it in the woods until I was done sugaring. Was a big time/effort saver. Might build another this year and keep them in different areas for use when needed.