Need Opinion on Tapping Big Old Trees Previously Tapped by Others

[TapTapTap]

My new sugarbush expansion is on leased land. It has about 700 taps with many large hard maples. My challenge is that it has been used on and off as a sugarbush for a long time - I can spot the old sugarhouse on a 1942 aerial photo.

So my question is how to structure my tapping protocol. It's not clear that the prior operations used any method. Most trees seem to have old tap holes in concentrated areas and not systematically located. Since they're mostly large diameter trees, I could work the areas that appear to be mostly free of old tap holes and offset horizontally and vertically each future year. My other option would be to tap below the lateral since all of the visible old holes are up high. This below-the-lateral program would allow me to start fresh in hopefully clean wood, better identify my old tapholes during future seasons, and may be healthier for the tree.

Any thoughts?

Other info:
- I'm on high vac
- The trees are generally very healthy, tall, with large canopies. Many are 30" plus diameter.

Thanks for any advice. I feel like I have a team of professional maple consultants!

Ken

[Pdiamond]

I'd start low and only put in two taps per tree and no more.

[TapTapTap]

I only do two taps per tree in accordance with good tapping practices for high vacuum.

[BAP]

For trees that big, I would make sure to put on longer drops than you normally would so that you can reach all the way around the tree.

[DrTimPerkins]

Excellent application for tapping below the lateral. Just be sure your spout/dropline sanitation practices are very good.

[ddociam]

Would you elaborate on what are best practices for tap and dropline sanitation protocals?
Are you speaking mainly of changing spouts every year, and droplines every three? Cleaning every spring with Sodium Hypochlorite.
Drilling a clean circular taphole? Is there anything else?
I am beginning to switch over to cv spouts.
Is there any value to wiping off with alcohol before tapping.

[ennismaple]

If they cluster tapped the lines you should still be able to find lots of good sapwood. I'd go 2 taps per tree for the big ones with a minimum 36" droplines but you may even want to go longer so you can reach the back side of some trees. We have some monster maples that have "custom" droplines we used that are up to 5 feet long to allow us to tap the entire circumference.

[TapTapTap]

This is my first year on this woods so they're all new drops. I bought half/half 36" and 40" drops - after installing a 100 or so I wish I'd gotten all 40s. For this first year, I'm using CDL clear 5/16" signature spouts and plan to switch over to cv taps next year and for the following year, or two. Then I'll change out the drops and start again.
Ken

[TapTapTap]

If they cluster tapped the lines you should still be able to find lots of good sapwood. I'd go 2 taps per tree for the big ones

The old taps are kind of clustered but that makes it challenging to have a consistent pattern. For number of taps I'm doing 2 maximum since we're on high vacuum.

Ken

[TapTapTap]

Excellent application for tapping below the lateral. Just be sure your spout/dropline sanitation practices are very good.

Dr. Tim - you make an excellent point and made me rethink my strategy. Since the drops are new, and I already bought my non-cv spouts, maybe I'll do this first year on the drop above the lateral in areas that look best for tapping. Then next year, I'll do the cv spouts below the lateral. When I cycle out my drops I can go back to the non-cv spouts above the lateral and back below afterwards.

Ken

[blissville maples]

I would simply look for a somewhat lively healthy spot, if you can identify old wounds try tapping 4-8 inches either side and higher or lower in hopes of not hitting dead wood since you know a taphole was close but not close enough for dead wood. I would like to assume there would be an untapped area of wood capable of receiving a viable taphole in this scenario.

Also on these larger trees I usually add a third tap for two reasons. 1 if one tap does hit less than par wood you hopefully have 2 others on a 30" tree and not one. 2. 2 taps on a tree this size is simply not enough (unless your simply trying to impress everyone with your high gpt numbers) if you have a short run of 4-6 hrs you at times won't exhaust all of the sap potential for that day. I like the example of a bucket of water one with one hole and one with three holes under a given amount of time the one with a single hole may not completely empty whereas the other would. This can apply to a tree.
So say 500- 30" trees of 2 taps a piece yields .6 gpt that's 600 gallons of syrup. Add a third tap and now your up to 1500 taps however you may only achieve .45 gpt but that's still an overall gain 75 gallons- but you lose your bragging rights of high gpt figures lol!! The numbers may not be exact but the idea is there!!

I have a 930 tap Sugarbush in one area mostly say 80% old trees 30 inch plus, and at one point it was tapped years ago as I found an old metal spout left in. This is my most remote site on generator and many times when I get there I am too late and the sap is already running in on gravity. Last year I collected 32k gallons of sap from this site. I use 60 gallons of sap average through the season to make a gallon of syrup. So this sugar bush produces well, I have a few trees closer to 40" with four taps......I do not overtap like many who would have 5-6 taps in these trees, my second tap tree is atleast 16-18". but I know these older 30"+ trees have alot of sugar to offer!!

[TapTapTap]

Blissville - Thanks for the ideas. I agree it won't hurt anything to be a little liberal on the tapping of the largest trees. And, i'm looking forward to getting alot of sugar from them. Have a good season.
Ken

[DrTimPerkins]

... my second tap tree is atleast 16-18". but I know these older 30"+ trees have alot of sugar to offer!!

It all depends on how much vacuum you are pulling. If you're on gravity, a second tap will yield a varying amount of sap, approaching double that of one tap on larger trees. Most of the sap flow during the exudation period is downward. Lateral (sideways) movement is fairly limited.

On high vacuum the situation is considerably different. Sap can (and does) initially flow downward (the pressure gradient is initially down due to gravity), but over time, can also flow sideways across the stem, so you're collecting sap and sugar from a much broader area. This is why vacuum produces more yield than gravity. During a really long flow, sap can also move upward in the stem from below the taphole upward.

Therefore, a second spout in a 16-18" tree on high vacuum is not normally going to give you much additional syrup yield. Now on a 30" tree it might produce 1/3 - 2/3 more sap. A 16-18" tree on high vacuum will give you 0-20% more sap depending on how the year plays out. The problem with adding those second (or third) taps only exacerbates the problem because it means there is even less good wood to tap into in future years. Those big trees will put on the same amount of wood growth on a total area basis as smaller diameter trees, but because they are so large the rings are narrower because that new wood is being put on over a much larger circumference. This reduces tapping sustainability in those really large trees with many tapholes.

Figure below shows the amount of sap collected with one or two taps under high vacuum (red maple). In 2019 there was a bit more with the 2nd tap. In 2020 there was almost an identical amount collected with one or with two tapholes.

21875

[TapTapTap]

Figure below shows the amount of sap collected with one or two taps under high vacuum (red maple). In 2019 there was a bit more with the 2nd tap. In 2020 there was almost an identical amount collected with one or with two tapholes.

21875

Dr. Tim - was the figure from a study on a certain size of tree?

Do you have a recommendation for what size tree to go with the 2nd tap? It sounds like the 30" trees are worth the extra tap.

Ken

[DrTimPerkins]

Dr. Tim - was the figure from a study on a certain size of tree?

Do you have a recommendation for what size tree to go with the 2nd tap? It sounds like the 30" trees are worth the extra tap.

The range was from about 13.5" to 20" dbh. We were trying to determine if there was a breakpoint somewhere around where the recommended (15-18") second tap size, so we didn't go really high. Within that range the gain from the second tap was low or negligible. Doing larger trees on the list for future studies, but is logistically difficult because it means we have to move 30 chambers and vacuum lines to a whole new section of woods (with large trees). We're now about to start the 3rd year of a 2 yr study on 1 vs 2 taps :confused: , and will repeat it again in the 2022 season, so as you can tell, the answer hasn't been as clear cut as we'd like. There is no doubt that putting in a second tap at some point becomes economically worth doing, but if you're using high vacuum, it clearly is not anywhere down in the range commonly cited. There might end up being 2 or 3 recommendations depending upon whether you're on gravity, vacuum, or high vacuum. To make it even more complicated...that is coming at it simply from a total sugar yield. If we consider wounding and tree growth in those really large trees, the answer gets even more confusing.

All that said, I'd put 2 taps in those 30" trees. Put one up high and the other on the opposite side down low (below the lateral) to get them as spatially far apart as you can. Also be sure to check the wood when you're tapping to make sure you're hitting good white wood.

[blissville maples]

Every 10" of tree girth has an amount of tapping band. A 30"+ tree has alot of tapping band.... then figure in the fact all you have to do is change the height of your ladder line by a foot or two to gain a whole new tapping band!

I do believe on the long runs that third tap may not help a whole heck of a lot but I can tell you on the shorter runs that only happen for a few hour. s up to 6-8 hrs this third tap will help your yield but it won't help your numbers.

I can't remember which study it was, I've read probably every one of them, may have even been from Proctor maple that showed on short runs an extra tap will help empty that tree before it freezes back up.

At any rate I don't think you're going to hurt that tree much given the size of the tapping band. I am still deciding if I like quarter inch or 5/16 spouts but with the quarter inch your not going to hurt that tree any!

[DrTimPerkins]

Every 10" of tree girth has an amount of tapping band. A 30"+ tree has alot of tapping band.... then figure in the fact all you have to do is change the height of your ladder line by a foot or two to gain a whole new tapping band!

Not sure that math works out (10" of additional circumference is only 3.1" greater diameter, it takes 31" of circumference to equal a 10" diameter tree), but the general concept is correct. Larger tree = more tapping band. The complicating issue is that as a tree gets larger, its growth rings get smaller, so it takes more time for fresh wood to grow over a previously tapped spot on a large tree than it does on a smaller tree.


I do believe on the long runs that third tap may not help a whole heck of a lot but I can tell you on the shorter runs that only happen for a few hour. s up to 6-8 hrs this third tap will help your yield but it won't help your numbers.

Yes, with shorter sap flow periods, a second tap will access more sap. The issue is not simple. So whether you get no additional sap from a 2nd or 3rd tap is dependent to some degree upon how the season plays out. A lot of very short runs = larger increase in sap yield from a 2nd (or 3rd) tap. Fewer long runs means no difference. The aspect that you tap on also plays some role in the yield and how any one sap run plays out. The problem is knowing what the season will be like.


I can't remember which study it was, I've read probably every one of them, may have even been from Proctor maple that showed on short runs an extra tap will help empty that tree before it freezes back up.

Correct, but also influenced by aspect. If the north side never thaws in a run, a second tap there won't help. If it does thaw, then it can help.


At any rate I don't think you're going to hurt that tree much given the size of the tapping band. I am still deciding if I like quarter inch or 5/16 spouts but with the quarter inch your not going to hurt that tree any!

Depends on a lot of factors, including prior tapping history. If several 7/16" taps were used for several decades, finding good wood above the lateral line can be problematic, especially if the trees are growing slowly. Best to check the wood shavings when tapping these large trees (yield is reduced proportionally to the amount of stained wood that is hit) and tap below the lateral if there is a problem finding good wood.

We found several yrs ago that 1/4" spouts yield about 10-11% LESS sap than a 5/16" spout at the same depth (this was later verified by Centre Acer), although the wound is a bit smaller also. Can be a useful approach for some folks, as long as they recognize that yield is lower.

Perhaps of interest to some folks, but 1/4" spouts are now marketed as producing the same (or near) the amount of sap as a 5/16" spout. Not quite true (they produce 10-11% less), but in any case, this is NOT why they were introduced into the market. Back in 2008 when syrup was scarce and prices spiked (to $4.00/lb) due to back-back poor seasons in Quebec, maple manufacturers introduced these spouts with the thought that people could tap in the fall to make syrup, then ream the hole to 5/16" in the spring and make more syrup. That approach didn't pan out, but the manufacturers had already invested in the molds, so they came up with another marketing approach...same amount of sap but smaller wound. The first part (same amount of sap) is not quite true. Slightly smaller wound is.

Overall though...good discussion and nice to hear that you folks think about such things in deciding on your tapping decisions. That is exactly what should be done...educate yourself on the factors involved and the consequences of certain decisions, then go with what you determine to be the best course of action in your woods.

[TapTapTap]

Overall though...good discussion and nice to hear that you folks think about such things in deciding on your tapping decisions. That is exactly what should be done...educate yourself on the factors involved and the consequences of certain decisions, then go with what you determine to be the best course of action in your woods.

Thank you Dr. Tim, and others. I got a lot out of the discussion.

[blissville maples]

Never ceases to amaze me how many variables are involved......many things to ponder

Interesting about the 1/4 taps. I did see the results on a video from pmrc. I was told from my dealer on high vac there is no difference now I don't know who to believe- I'll have to ask if he uses the 1/4"!!.......I have fairly accurate records from all my tanks. One has always been 5/16 this year they are all 1/4 " - I'll be looking forward to the totals at the end of this season.

I will say I was skeptical in using them because yes your puncturing less vessels, on the other hand if we pull sap upwards out of the ground i would have thought that this 1/4 spout would sufficiently vaccumize the area to extract that sap. ... some things are extremely hard to recognize I suppose

[DrTimPerkins]

Interesting about the 1/4 taps. I did see the results on a video from pmrc. I was told from my dealer on high vac there is no difference now I don't know who to believe.

We've measured it over a couple of years and found a 10-11% drop in sap yield from 5/16" to 1/4" spouts. Centre Acer did the same thing and found -- a 10-11% reduction in sap yield.


I will say I was skeptical in using them because yes your puncturing less vessels, on the other hand if we pull sap upwards out of the ground i would have thought that this 1/4 spout would sufficiently vaccumize the area to extract that sap. ... some things are extremely hard to recognize I suppose

It goes back to the thing we were talking about earlier -- the RATE at which you can pull sap from the tree is also important. With high vacuum you can pull plenty of sap out of a tree even with a tiny taphole and a hypodermic needle (we've done it), but you just can't get it out fast enough before (most of the time) the tree freezes up again. Some sort of thing with 1/4", 3/16" or smaller (microspouts) tapholes/spouts. In the right year with lots of long thaws maybe you would find the same sap yield, but in most seasons, you're going to get (on average) 10-11% less.

Going back to the "pipe" model of a tree. If we have a pipe filled with water, whether we drill a big hole or a tiny pinhole, given enough time all the water would flow out down to the level of the hole. But if we only have a certain amount of time for the water to drip out, the pipe would empty would a big hole, but not with the pinhole. Same concept.

10-20% is pretty much on the order of where most maple producers might begin to notice a difference given the season/season changes. That's why we always do lots of replication with control treatments to provide a baseline to compare to and do experiments over several years in order to get good results.

[GeneralStark]

Also on these larger trees I usually add a third tap for two reasons. 1 if one tap does hit less than par wood you hopefully have 2 others on a 30" tree and not one. 2. 2 taps on a tree this size is simply not enough (unless your simply trying to impress everyone with your high gpt numbers) if you have a short run of 4-6 hrs you at times won't exhaust all of the sap potential for that day. I like the example of a bucket of water one with one hole and one with three holes under a given amount of time the one with a single hole may not completely empty whereas the other would. This can apply to a tree.

By this logic shouldn't you be putting at least two taps in every tree? And given that trees are not buckets, I fail to see how your analogy is relevant here...

[johnallin]

By this logic shouldn't you be putting at least two taps in every tree? And given that trees are not buckets, I fail to see how your analogy is relevant here...

Don’t think that was needed...Dr Perkins covered it very well already... do hope sap starts pretty soon.

[blissville maples]

By this logic shouldn't you be putting at least two taps in every tree? And given that trees are not buckets, I fail to see how your analogy is relevant here...

Not if you understand that a tree of larger diameter will have more liquid to extract, with that said a smaller tree does t require more taps to evacuate all the sap. If you've ever looked at the analysis, and frankly use common sense, larger trees have a lot more liquid in them obviously because of their size. But yea dr Tim explained it well.

It's like a keg of beer takes a lot more people to empty one versus a bottle!!

Trees are not buckets you are right, it represents a column of water....I suppose if I said a Culver that would of made it clear!! More or less every hole in a tree, bucket, column of water, gas tank, swimming pool whatever analogy you'd like to use will empty whatever reservoir it punctures more quickly than less holes. It's a fairly simple analogy.

Same as Doctor Tim explained between quarter and 5/16 taps there is I believe around a 40% difference in hole size between the two. Obviously one will evacuate liquid quicker than the other, which I didn't think would make a big impact but im about to find out!

[DrTimPerkins]

Analogies are never perfect, but just simple ways to get the main concepts across. Obviously trees are a lot more complicated than hollow pipes stuck in the ground, but the example works fairly well for a lot of things.

[TapTapTap]

I ended up doing 2 taps on trees at about 22 inches and up. I used a mathematical analysis rather than scientific.
I'm using 40" drops and assuming a 30 deg shallowest angle, you get a reach of about 35" around the tree. So it can reach 35" in either direction, or 70" circumference which is a 22" dia tree. A single drop on larger trees would not reach the entire tree.

Even run flat, a 40" drop would only cover a 25" tree.

[DrTimPerkins]

I used a mathematical analysis rather than scientific.

You used both...math is a science. :lol: Either way you look at it, the reasoning is sound.

[TapTapTap]

You used both...math is a science. :lol: Either way you look at it, the reasoning is sound.

You're right. But I'll take it one step further - It's engineering. A combination of math, science, economics, practical experience, and common sense.

Ken

[DrTimPerkins]

You're right. But I'll take it one step further - It's engineering. A combination of math, science, economics, practical experience, and common sense.

Ken

tou·ché sir...

[TapTapTap]

I did about 20 percent taps below the lateral. It takes a little getting used to when you're scanning the woods. First glance looks like it's not plugged in and needs to get fixed.

[DrTimPerkins]

Yes...it does look odd at first, but I bet you didn't hit a bit of stain during tapping...which is exactly the reason to do it. Let me know what you think of the approach after the season is over Ken.