Can I lift sap without a mainline?

[MarquisVII]

I currently have two of my five 5/16 lines running 100-200ft into my neighbor's yard and the topography is a downward slope towards the end of each line, so I'm tapping about 8-10ft above ground on the last few trees of each line to keep it level. About 12 taps on each line. I would like to reach further down the slope where I could grab another 15 or so trees, but I have no interest in tapping 12-15ft above ground, nor will I risk running 5/16 downslope. This year my vac at the manifold was consistently 24" minimum but I saw it creep as high as 27" a few times, so I'm pretty happy with the status quo.

1. Could I put a reducer on the end of each existing line and run 3/16 further down the slope, meaning I would be sucking sap uphill in the 3/16? Would this cause enough loss of vacuum/yield on the existing taps that it would negate the sap from the additional trees?

2. Possibly run a single 3/16 all the way to the downslope trees, bypassing any trees closer to/level with the pump? I have a 7-way manifold on the Shurflo (one is recirc), so would having one line on 3/16 screw up the vac on all the other 5/16 lines?

3. Sap ladder. I don't have mainline, so in this scenario I would "plateau tap" the downslope trees with 5/16 and use a 3/16 sap ladder up into the existing 5/16 lines - is this even a thing? And is this basically the same difference as #1?

[Bricklayer]

We have a lot of lateral runs like that. It would have been a pain to get mainline into some of these areas. And instead of dealing with more sap ladders we just ran negative slope laterals and used CV’s on the taps. They work and the sap moves through. A lot slower than the other laterals. But it works. And we are running 26” when it’s tight but generally 24”. So you should be fine. It’s not ideal of course. Your Probley not getting the most sap possible from those trees. But it’s more than you would be if you didn’t tap them.

[MarquisVII]

Thanks, Brick. When you say you have a lot of lateral runs like that, do you mean 5/16 lines reduced down to 3/16 to grab the negative slope?

Curious for anyone else's input as well.

I should also note that next year I will upgrade ALL of my taps to CVs.

Thanks!

[maple flats]

While extending 5/16 reduced to 3/16 will have a slight benefit, it would be far better to run 3/16 the entire distance. Understand that it would work but far less than if you had a collection point at the low end and then a pump that would push the sap uphill as far as needed. Consult a chart for the "head" needed to push that high. The farthest a vacuum could lift is just about 20-21' if the vacuum is perfect and line friction will reduce that.
One fact can help, as I discovered when I had 3 lines in 3/16 tubing collecting sap from a low section across a driveway from my sugarhouse. Trees in times of good sap flow can have up to 30PSI or more in the tree. As I tapped 25 trees in the low area while the sap was flowing, years ago, I tapped the farthest tree and worked my way back towards the sugarhouse. Just before the sugarhouse I put an ell in the line and ran the 3/16 tubing up about 15' (total lift about 19' from the low end to the driveway crossing) to a limb on the side of the driveway, then across driveway to another tree, over a limb and then down at about 30 degree fall to the mainline which was on 27" vacuum. I was surprised how well the pressure in the tapholes pushed the sap up and over the driveway and how wet I got as I added the saddle and tried to connect that line to the saddle. I then did it again and added 24 more taps on red maples and it was the same. The following season I added a third but those were tapped before the sap ran, but during the season I watched the bubbles display the flow in all 3 lines at so close to equal in all 3 I could not determine if they were equal or not.
It has been pointed out to me several times that I was not getting all of the potential had I run downhill, then pump the sap on a return line, but my view was that in the process I had added 75 taps with minimal investment and visually the flow was impressive to watch. In those 3 lines one (25 taps) was all sugars, the other two were all reds (24 +26 taps).
Over the next few years I added about 150 more taps in 6 more 3/16 lines each with 23-27 taps each, so that I had added 226 taps from low areas that I could not reach otherwise without a much larger expense in pumps, saddles and return lines. Each line in 3/16 , besides the lateral tubing, taps and tees only required one saddle each for an average of 25 taps, rather than up to 8 or more saddles each. With all these, I still was getting .41 to .48 gpt over the 6 seasons I did this, maybe had I spent the extra I might have gotten the half gal/tap some others get but I was happy.

[MarquisVII]

I like what I'm hearing, Dave. And I have no interest in the additional labor and expense of collecting downhill and pumping up. So in my case it seems I would be best to do a new line, all 3/16, with the "plateau tapping" method on the lower trees and then have a single lift point where I run the line vertically up to the height of my existing lines (this would be maybe 8-10ft max) and from there to the Shurflo. Basically a sap ladder without being a sap ladder. I'm guessing there's research that shows short vertical lifts produce more sap than longer but slight negative slopes (hence the invention of sap ladders)?

[maple flats]

MarquisVII, I had an old BB4 (piston pump with 27" vacuum that I did it with), I'm not sure if a sureflo will work, just try it and see.