Why not 1/4” Leader Check Valves?

[corrowbasin]

With a lot of producers switching to 1/4” on high vacuum, I figured Leader would have produced the check valve spout and or adapters in 1/4” by now. Especially with the 2021 CDL catalog making reference to tapping 25.5” circumference trees. (That’s a 8” tree)

[DrTimPerkins]

Not really getting at your question, but this is slippery slope material here. Why are people thinking about using 1/4" spouts? Some will say because it produces a smaller wound -- but for sure it will produce 10-11% less than 5/16" spouts. Very few admit it is so they can tap smaller trees. So what about microspouts (5/32")? Why not tap 4" trees with microspouts? I can tell you for certain that a 4"-8" tree is not producing much sap, and the sugar content tends to be low. It really comes down to proper management to allow crop trees to grow properly. If you're doing that, there probaby aren't a lot of 4-8" trees out there, except those that are replacement trees for your current crop trees. If that is the case, you shouldn't be tapping them.

From a carbohydrate perspective, the amount of sugar you're removing from a large tree is miniscule...even under high vacuum it tends to be under 2%. For those smaller trees growing in the understory though, life is a lot harder. They aren't getting a lot of sun, so it turns out the amount of carbohydrate you get from the tree is in the 12-18% range. You can think of that like an annual percentage rate on a loan. Nobody has any problem paying 1-2%, but you'd be quite unhappy about having to pay 12-18%, and having to do that doesn't leave a lot of funds to do other things (like GROW).

Lastly, you'll very quickly run out of good wood for tapping on a small tree with slow growth rates. 1/4" spouts will help delay that to some degree, but won't stop it from happening.

As for why Leader doesn't make a 1/4" spout...you'd have to ask them. The 1/4" spout was developed (back in 2008) NOT to allow tapping of smaller trees, but to allow fall tapping with reaming to 5/16" in the spring. This was when there as NO sap left in warehouses anywhere, and prices spiked. In order to get SOME syrup in the marketing pipeline, some equipment dealers came up with that idea (1/4" fall, 5/16" spring). Didn't work well (fall tapping followed by reaming doesn't produce much sap in the spring and creates a huge wound). Manufacturers had the molds for 1/4" spouts, so they needed to develop a market for it, which is why you see it suggested now that it makes the same amount of sap as a 5/16" spout (it actually produces less), but creates a smaller wound (which it does) so you can tap smaller trees (not a great idea).

[hogisland42]

I have been using 1/4" spouts for a 5 or 6 years and honestly don't notice a difference in my sap totals from when I used 5/16. I know science may say that I will get less but I don't see a difference. I don't use them in order to tap smaller trees but just like the smaller wound. I wish they made cv spouts in 1/4", I would definitley try them

[DrTimPerkins]

Both UVM PMRC and Centre Acer (Qbc) have done controlled studies on this, and found EXACTLY the same results. A 10-11% decrease in yield between 5/16" and 1/4" spouts. In both cases the research was done under vacuum conditions.

22163

It is not surprising that producers wouldn't notice a difference on a change this small. Given the magnitude of seasonal fluctuations in yield, changes in equipment, and different operating parameters, a change of 10-11% gets swamped out in the "noise" pretty quickly. That is why we do studies with controls, multiple replications, and careful measurements. Even so, detecting a change on the order of 5% is about as good as we can get unless we go to very high numbers of sample points and do the study over several years.


I wish they made cv spouts in 1/4", I would definitley try them

You would need to bring this up to the folks at Leader Evaporator Co.

[jrgagne99]

Dear Doctor,
Is there a companion study on the size of the wound area for the various tap-hole diameters shown in the chart above?
Thanks!

[DrTimPerkins]

Yes, but we aren't talking about it much until we get more data, so please don't take these numbers as gospel. In general, 5/16" spouts produce about half the wound VOLUME as a 7/16" spout. 1/4" spouts produce about 25-30% less wound compared to a 5/16" spout.

Wound size can be quite variable from tree to tree. Some are just better at compartmentalizing than others (much the same way that different people respond differently when healing). Small trees in the understory tend to have very tight growth rings, and seem to have smaller wounds.

NOTE that there is NO DIFFERENCE in wound size between gravity sap collection and vacuum sap collection. Said another way, vacuum (and the level of vacuum) sap collection does not increase wound size.

Likewise, it is important to note that the stain that forms in a tree does NOT represent the only area that sap or sugar is coming from. There is some overlap to be sure, but the physiological processes of sap flow and wound response are two very different things physiologically. The only real overlap is that both sap flow and wound response are responses to drilling a taphole.

[corrowbasin]

I only bring up the idea of developing an 1/4" check valve as one of our sugar woods is almost strictly soft maple. We find the staining and wound response using 1/4" to far outweigh the potential loss in yield, over tapping with 5/16". Frost/taphole cracking on young fast growing soft maples is another one we noticed that occurs far less when tapping with 1/4" over 5/16". With Maple equipment distributors recommending tapping 8" trees (we do not), at least 1/4" spouts would prolong the conductive tapping band.

[fred]

in ohio we have several that have used 1/4" since they came out. still around 1/2 gallon per tap. wounds heal- almost undetectable- by end of summer and the stain is greatly reduced. win win as far as i can see.

as for the cv 1/4, i dont see it coming. since they changed the CV spout being made currently it doesnt work like they used to. but their fittings dont as well. hopefully they get it worked out but they do have bigger fires.

[DrTimPerkins]

Frost/taphole cracking on young fast growing soft maples is another one we noticed that occurs far less when tapping with 1/4" over 5/16".

Since you mention it, frost cracking in smooth-barked soft maple is a surface phenomenon that doesn't extend down into the wood. Doesn't seem to cause lasting damage in any case. Sure does look like it'd be bad though. Yes...a smaller hole will close over faster than a larger hole.


With Maple equipment distributors recommending tapping 8" trees (we do not), at least 1/4" spouts would prolong the conductive tapping band.

Yes...equipment dealers have come up with several ways to market the 1/4" spout since the reason they were developed wasn't valid. They already paid to have the molds made, so have to make some money off of them.