maple research

[DrTimPerkins]

Looking for input....

Keeping in mind that depending upon the question, the funding, the time we have available, and interest...

What types of questions do you have that you think we might be able to address via doing a research project?

No promises, and it can take years before we get through the process (in many cases we like to have 2-3 seasons of results before we talk about it), but just interested in hearing some ideas. The bigger the question, the harder and longer it can take...and not all questions are readily answerable. NO promises that we'll actually do these, but something might work out. Note that if you ask something that has already been done I may just point you to the resource with the answer.

[Biz]

I would be interested in data regarding the operation of vacuum on sap production, for the case where the pump is running continuously, versus pump turned off when sap stops running (lines frozen). My specific question is related to small diaphragm pumps such as Shurflo or the Bosworth Guzzler, but this could also apply to larger pumps. With the larger vacuum systems, folks typically leave the vacuum running 24/7 during the season, except when there is an extended freeze. Diaphragm vacuum pumps are typically turned off when sap is not running (at night), to conserve battery power and/or to avoid damage to the diaphragm during extended running dry or running with potential ice buildup internally. Manufacturers often recommend that the pumps should be turned off and drained in freezing temps. I would be curious to know if there is a sap yield penalty if the pumps are turned off at night, if so how much. It is often not possible to keep the pump warm at night. Perhaps this has been studied before, if so a link would be appreciated. Thanks.

Dave

[DrTimPerkins]

Funny that Dr. Abby and I were just talking about this earlier today.

[berkshires]

This is probably a very basic question, because I'm a total novice. What are the factors that you can use to guess relative sugar content of a tree. I have way more trees on my property than I have time or boiling capacity for. So I want to pick the best ones. The most obvious factor is:

- Crown size.

But what else? Is there any relation to things like:

- On a steep hill, the direction the hill is facing? Like, will a north-facing tree have lower sugar than a south-facing tree?
- Size of the trunk?
- Color of the leaves? Will a tree that always has brown leaves perform better or worse than one with bright orange leaves?
- How late the tree holds onto its leaves? Some trees seem to drop their leaves at the first sign of frost, while others still have bright green leaves.
- Anything else?

Thanks!

Gabe

[DrTimPerkins]

What are the factors that you can use to guess relative sugar content of a tree?

It is difficult to predict the SSC of a tree. Big trees with wide crowns growing on good soils are best, but there isn't a good way to distinguish one tree from another growing side-by-side. Best approach is to test them with a refractometer (using appropriate technique). Just know that SSC can vary a lot over a season, so best to measure groups of trees all on the same day (and within a few hrs of each other) if possible.


- Crown size.

Slight relationship, but difficult to measure, so diameter (dbh) is used more frequently. In general though, canopy trees will tend to have a slightly larger SSC than understory trees.

- On a steep hill, the direction the hill is facing? Like, will a north-facing tree have lower sugar than a south-facing tree?

No relationship has been demonstrated.

- Size of the trunk?

Only in terms of whether it is a canopy tree or not. Larger trees tend to be canopy (dominant or codominant) trees, so SSC tends to be higher.

- Color of the leaves? Will a tree that always has brown leaves perform better or worse than one with bright orange leaves?

There has been some research showing that trees that tend to be more "red" tend to have somewhat higher SSC.

- How late the tree holds onto its leaves? Some trees seem to drop their leaves at the first sign of frost, while others still have bright green leaves.

Green leaves lower, yellow moderate, red higher, but the relationship is fairly low.

- Anything else?

Nutrition. Good nutrition, particularly calcium (maples really like calcium) tends to produce more chlorophyll, more photosynthesis, more growth, higher SSC and more sap. But keep in mind that too much is not good either.

We do have some data and have been doing some analysis for a few years on what environmental or biological variables tend to be associated with higher SSC. Lots more work to do on this, but in general, there is a genetic maximum potential SSC trees can attain (which is quite variable from tree to tree). Once you stray outside the "norm" for weather or stress factors (drought, hot weather, etc), then you tend to drive SSC downward from the genetic potential.

An "oldie but goodie" on SSC can be found here http://www.uvm.edu/~uvmaple/sapsugar...tvariation.pdf Work by Dr. Fred Taylor (deceased), one of the founders of the UVM Proctor Maple Res Ctr.

[eagle lake sugar]

I was giving a sugaring class in adult ed and the guy monitoring the classes was from the cooperative extension I believe. He asked a good question that would be a great study. He mentioned how they use fertilizer spikes for various trees they plant and the amazing difference it makes in tree health, crown etc. He asked if I considered doing that for my maple trees. It seems like you could fertilize trees close by to others and tell very easily if there's a difference in crown size, sugar content, etc.

[berkshires]

Thanks Dr Tim, this is really great info!

Cheers,

Gabe

[Aaron Stack]

Great to hear on the PFAS compounds - I won't have to change my plans for next year.

[DrTimPerkins]

Great to hear on the PFAS compounds - I won't have to change my plans for next year.

Note that I cannot certify that there is no PFAS in your or any particular syrup without it being tested, however in the testing that the Vermont Department of Environmental Testing did of maple syrup made from trees within the area of concern, PFAS was below the detection limit.

https://vtdigger.org/2016/04/13/mapl...on-tests-show/

https://dec.vermont.gov/sites/dec/fi...ts.N.Benn_.pdf

[Aaron Stack]

Has there been any research on the effects of localized water quality issues on sugaring? Some examples like a high sulfur content in the water (like in the Moosehead Lake Maine area - filters required for drinking water at the cabin we rent in the summer) , having a property next to but uphill from a transfer station (nice piece of land for sale), or in areas where perfluorinated carbons, better known as PFAS had been used in firefighting foam (this is a local issue impacting fresh water drinking wells surrounding our National Guard Airbase now), or even former farming pastures.

I've Googled a bit and can't seem to find anything about that sort of thing. I assume the impact would be a negative to sugaring, but with all the boiling perhaps that removes the issues normally associated with drinking it straight.