Reaming birch holes - any prior work, and proposal

[Snowy Pass Maple]

Building off a discussion in another thread -

It seems that there is pretty broad consensus that reaming a maple hole has a very "short" benefit but it works for some.

What I'm wondering is if anyone has experience doing this on Birch. With a season measured in days rather than weeks, even a short extension could be of significant value in total output. And it's a problem I might be facing after a heat wave in our area during the first week the birch taps were in.

I'm also not sure if it is well known on birch whether holes will slow down more from drying up structure in the tap or biological contamination. And with birch flowing much more prolifically in general, I'm not even sure that the taphole is capable of slowing down in 2-3 weeks as this should have some natural flushing benefit to keep things cleaner. This could be tested as well with and without and alcohol rinse. And then there is the question of how it would impact closing the hole when done.

In the name of science, I'm willing to try it on a few trees if nobody else can point me to any concrete answers on the above.

My thoughts would be to pick a subset of trees and:

- Pull tap
- (optional) - Rinse hole with alcohol to kill any microorganisms creating problems
- Re-drill with sterile bit - I'd probably stick with the same 5/16" - I could try a couple 7/16" for comparison but I wouldn't want to encourage this - I liked a clever idea on another thread of starting with 19/64 and reaming to 5/16...
- (optional) - Possibly rinse again with alcohol
- (optional) - Allow sap to flush any residual alcohol out
- Install new tap/drop tube to bucket

I'd try to measure the performance by comparing the buckets pre-reaming and post-reaming vs. some average of nearby control buckets through the same period.

Any other ideas on how to design the experiment?

[BC Birch Tapper]

I've also heard of retapping in another part of the tree, but we don't typically recommend such actions. Usually 1 tap /tree /year & move around the tree as years progress a few inches away & up or down due to the compartmentalization that occurs in the tree as a result of the wound
Other options, if you have plenty of trees use a new tap for a new tree.
I also like your 2nd option, start small & go bigger.
We will replace taps & or buckets especially in the last week of the season usually on < 5 % of trees that are impacted although we haven't had the summertime temps that have been happening on the east coast.
I've also seen cut tree stumps run more on one side than another, usually the sunny or southern exposure. When warm temps arise though it is good to have your bucket on the shady side or north ish.
A tap & tube can accomplish this.

[DrTimPerkins]

...I liked a clever idea on another thread of starting with 19/64 and reaming to 5/16...

So let's think about this a little. Going from 19/64" to 5/16" is a change of 1/64" total. Split that between either side of the taphole (or top and bottom of the taphole if you prefer) and you're removing 1/128" (or 0.0078 inch) of wood in total on each side. Not enough to do anything, and certainly not enough to remove any microbial growth from the taphole and surrounding wood tissue.

So maybe you go from 1/4" spouts to 5/16". That equates to removing 1/32" (0.03") of wood from each side of the taphole. Still not enough to make much of any difference.

Any study I've seen shows that reaming is marginally effective at best. It might increase flows temporarily, but doesn't usually amount to much real sap gain. It is feasible for smaller producers with 10-200 taps perhaps, but certainly not economically beneficial for larger producers given the labor costs.

I'm not recommending it, but if someone were to ream tapholes, it would make a lot more sense to simply drill the taphole a little deeper.

[Snowy Pass Maple]

So let's think about this a little. Going from 19/64" to 5/16" is a change of 1/64" total. Split that between either side of the taphole (or top and bottom of the taphole if you prefer) and you're removing 1/128" (or 0.0078 inch) of wood in total on each side. Not enough to do anything, and certainly not enough to remove any microbial growth from the taphole and surrounding wood tissue.

So maybe you go from 1/4" spouts to 5/16". That equates to removing 1/32" (0.03") of wood from each side of the taphole. Still not enough to make much of any difference.

Any study I've seen shows that reaming is marginally effective at best. It might increase flows temporarily, but doesn't usually amount to much real sap gain. It is feasible for smaller producers with 10-200 taps perhaps, but certainly not economically beneficial for larger producers given the labor costs.

I'm not recommending it, but if someone were to ream tapholes, it would make a lot more sense to simply drill the taphole a little deeper.

Agreed that the 1/64" is pretty marginal. The fact that it's a hand-held drill will also result in a certain amount of play/movement that may well exceed this in any case - I'd think that the 1/64" difference would only slightly enhance that. How deep into the wood structure does the microbial contamination reach?

If you had to choose between going from 5/16"->7/16" or adding a certain amount of depth to the taphole, which would you consider more damaging and why?

In another thread you had also mentioned that birch does not compartmentalize as well, so then that makes me wonder if you'd be better to explore options like this, then skip the tree an entire year, versus no reaming, but then have to tap trees every year to have enough for production in a given area.

I'm assuming all the reaming studies you mention are maple - but if there are any on birch, I'd love to read them. Do you have any links to studies on reaming or experience in terms of what the "short" period of benefit would be? With birch season being so short and sap production so prolific while it's running, it's important to know if short is 3 hours, 3 days, or a week - I'd consider a few days short for maple, but significant for birch. And in those studies, have people looked at using alcohol to try to avoid contaminating the newly drilled area?

I find the whole birch process interesting because there are so many things different than maple and it's a heck of a challenge in our climate at least. It seems that many assumptions that apply to maple (both technical and economic) don't directly carry over to birch and there seems to be much less consensus on best practices. But it's good to know what's been done in maple and then try to figure out what does and does not apply to birch!

Thanks for the input!

[Snowy Pass Maple]

I've also heard of retapping in another part of the tree, but we don't typically recommend such actions. Usually 1 tap /tree /year & move around the tree as years progress a few inches away & up or down due to the compartmentalization that occurs in the tree as a result of the wound
Other options, if you have plenty of trees use a new tap for a new tree.
I also like your 2nd option, start small & go bigger.
We will replace taps & or buckets especially in the last week of the season usually on < 5 % of trees that are impacted although we haven't had the summertime temps that have been happening on the east coast.
I've also seen cut tree stumps run more on one side than another, usually the sunny or southern exposure. When warm temps arise though it is good to have your bucket on the shady side or north ish.
A tap & tube can accomplish this.

Yea, I definitely don't want to do a new hole in the same tree - it's hard to imagine that's not far worse than even reaming the existing hole up to 7/16".

I did think ahead on the bucket placement - but that hot weather last week was so bad that it didn't protect me! Also finding that the RO filter gets nasty a lot faster with birch - even when processing in 40 deg temps.

When you replace taps, do you do any other cleanup on the taphole as part of replacing them?

As for trees, we have a lot, but not an infinite supply, so I'm not sure if it's better to do some sort of second reaming and skip a year, or just tap more once every year. Gets back to the question of what % increase in sap one could get with this approach, and relative damage vs. two unique holes.

[MillbrookMaple]

I just went into my woods to check my maple taps. They are not running so I decided to drill one of my yard trees and it was running well. So I went up into the woods with a 5/16 pulled out my check valve adaptor and reemed the hole making it slightly bigger around and slightly deeper. Sap started to come out of the tree instantly at a good rate. I put the CV back in and the vac is really making them run. Since we had such a horrible year we are going to reem all 500 taps that we still have left on line and try to make some more syrup this week. If it had been a normal year and I had all 1500 taps to reem I wouldn't. 2 weeks of no sap and warm weather was too much for the CVs. If your tap hole is dried up on the birch then reeming might be a good Idea if it is a problem of sap quality I'm not sure if that is do to microbes or just the sign of the end.

[Snowy Pass Maple]

MillbrookMaple -

You are more of a man than I if you can handle birch and maple simultaneously! :-) Holy cow birch run like crazy... they didn't even stop for the freeze we had. How are they doing up your way?

The sap quality I'm getting now seems really good post-bucket-washing - I'm not letting anything sit more than 12 hours, and if things keep running well, I'll do another preventative bucket powerwash this weekend to keep it that way.

No sign of any slowdown or microbial issues yet but I'm just thinking ahead if/when I see any issues - I'm pleasantly surprised that the nastiness in the buckets seems to had not found its way up to the drop lines and taps!

[MillbrookMaple]

The birch started to run again today some but not a whole lot yet. Yesterday they were just blocks of ice and the spouts still have some ice build up on them. It got down to 14 the other night so I'm not surprised.

[BC Birch Tapper]

The only other thing may be compass orientation, north vs south side of the tree

[Snowy Pass Maple]

I forgot to update on this - being a bit overwhelmed this year, I did not have time to setup a proper controlled experiment. But I did find one pair of trees where I had some crud starting in the lines and taps. As soon as I saw it, I did a fresh install of a sterilized tap, new tubing, and recleaned the hole a couple times using an alcohol soaked 5/16" bit - same size as the original hole. I didn't take much wood out at all like this. After re-installing, the pair of trees that got this ran really well for the rest of the season - over 5 gallons per day, and very clean/clear sap - it was one of the last buckets I pulled. Getting an extra week is pretty significant for the short birch season.

I was also very surprised how few of the droplines to the buckets ever had any contamination in them after 3 weeks - particularly given the week of extreme heat we had the first week. Only ~10% of the trees ever showed any evidence of growth in the lines. I did use an alcohol sterilized bit on each hole and perhaps those cases were evidence of my being sloppy. For now, it makes me more of a believer that the drill bit sterilization and extreme cleanliness on the initial installation is a very worthwhile step to take.

It also makes me think that it would not be crazy to have some longer tubing runs to a larger collection container - for example, 10-20 trees feeding a 55 gal drum. The tubing appears to have stayed so much cleaner than the buckets, that I think it would be advantageous to have more tubes feed one central collection drum that would be washed daily vs. wash so many buckets at each tree on a 3-5 day rotation. I have read that tubing installations are not used as much with birch, but I'm not sure if that is referring to permanent tubing networks vs. runs up to ~50 feet that are seasonal. I also wonder if the higher flowrate of birch sap helps flush the lines more effectively - there is not as much stagnation as with maple that starts and stops a lot.

[BC Birch Tapper]

Interesting about the reaming out of the holes. Makes sense & the alcohol cleaning is always a good idea.
As birch grows in clumps, many times we will tap multiple stems & have them flowing into a larger pail. It is important to keep the lines as vertical as possible so you aviod sap sitting in a trough in the line. I do know another tapper which has multiple trees on a hill going into a larger tank which they drain daily. We'll trade pails mid season as well if things get a bit yeasty but usually a clean pail will do the trick but we haven't had to deal with the extreme warm temps. I havent tried reaming ou the holes, but will give it a go. We're tapping today aout 300 trees. Game on!