Not Just Sugar Maples – Part II

Ohio Maple Days 2022 did not disappoint.  The food was fantastic, the vendor room crowded, and the presenters shared a wealth of knowledge of expertise across a wide range of subjects.  I was among those speakers, and Abby van den Berg and I presented a pair of talks that focused on those other maples.  Last week I shared a quick rundown of 20 short statements that summarize the Ohio work we have done from a high bird’s-eye viewpoint.  This week, we’ll check out Abby’s perspective from Vermont which focused on 4 central questions regarding red maples.  Before we get into it, be sure to mark your calendars for next year’s conference December 8th and 9th!

Abby van den Berg asked and attempted to answer 4 main questions of red maple.

  • Red maple, Are you as sweet as sugar maples?
  • Red maple, Do you have lower yields than sugar maples?
  • Red maple, Do you slow or stop running earlier than sugar maples?
  • Red maple, Does your sap make inferior or different-tasting syrup than sugar maples?

My main disclaimer, and one that I know Abby would echo, is that the answers she provided are pertinent and specific to a single research study in Vermont.  All of the answers should not be directly applied to Ohio, but there is certainly LOTS to learn and consider.  Why?  Well, Vermont is not Ohio, and this research is on reds and we have mystery maples.  So for a host of reasons – please learn from this incredibly interesting study, but do not directly project these results into your own woods.

FirstRed Maple, Are you as sweet as sugar maples?  The answer here is not a surprise, the answer is “no.”  Abby’s data was “very crude” by her own words, but Brix analysis shows that red maples track 0.2-03 Brix beneath sugar maples most of the season.  This is supported by our Ohio study and consistent with patterns we have observed.

SecondRed Maple, Do you have lower yields than sugar maples?  From the perspective of statistical difference, no – red maples do NOT have lower production potential than sugar maples.  In the Vermont studies, heavy sap flow counterbalanced the slightly lower Brix levels to result in similar production outputs between red and sugar maples.  Does this mean they are identical or equal?  Not necessarily, but per the study design, they are not different.

ThirdRed Maple, Do you slow or stop running earlier than sugar maples?   No.  The Vermont study produced no evidence that red maples slow down earlier than sugar maples.  Is this consistent with our Ohio results?  No.  Why?  We have some guesses and some hypotheses we’ve discussed, but this potential difference will be one to focus on as we learn more and more about these systems.

FourthRed Maple, Does your sap make inferior or different-tasting syrup than sugar maples?  A tasting experiment pitted red maple syrup (top row) against sugar maple syrup (bottom row) that was produced by trees in the same woods with the same methods at the same time under similar conditions as tightly controlled and identical as humanly possible.  Late-season syrup was deemed similar with respondents not able to differentiate between the 2 syrups.  Early-season syrup however did produce detectable differences in taste and profile.  Further research is ongoing to trace potential differences back to a source – was it a difference  in carbohydrates or invert levels, volatile aroma or flavor compounds?  Abby was not totally sure just yet, but I am sure we will find out what she discovers.  The most important finding here is that red maple syrup did not produce detectable late-season off-flavors as that is a common suspicion among maple producers.

You can read more about these results in the following article and recorded webinar:

Red Maple as Crop Trees for Maple Syrup Production

 

Not Just Sugar Maples – Part I

Ohio Maple Days 2022 did not disappoint.  The food was fantastic, the vendor room crowded, and the presenters shared a wealth of knowledge of expertise across a wide range of subjects.  I was among those speakers, and Abby van den Berg and I presented a pair of talks that focused on those other maples.  Abby’s perspective from Vermont and focused mainly on pure red maples (come back for Part II next week for those highlights), and my perspective sharing from the basis of our ACER-funded research on Acer freemanii, Freeman’s maple, or just “rilver” for short.  Before we get into it, be sure to mark your calendars for next year’s conference December 8th and 9th!

Let’s try this recap in a series of short statements.

1) Sugar maples are the gold standard for maple syrup production – there is no disputing that.

2) But other maple species probably deserve more love than they have traditionally been given.

3) Mounting pressures from climate change, forest pests, and a host of other reasons make other maple species more important to consider than ever before.

4) Because of the above, it makes sense to learn more about other maple species production potential.

5) We thought we had simple (red x silver) hybrid maples in the OSU Mansfield research sugarbush where we have our single-tree research stations.

6) We thought wrong.  Turns out the hybrid maples are more mysterious than that – stay tuned for further genetic testing!

7) Regardless of what other variety of maple we are working with it still made sense to compare their production potential and other characteristics to sugar maple.

8) Research began in the 2021 as we pulled over 20 sugar maples and 50 of the mystery maples into single-tree sap collection chambers that measured daily performance.

9) Research techs and research PI quickly learned that maple research can be icy cold!

10) The 2021 season was historically bad and we had 5 roller coaster runs total.

11) During the 2021 season, our mystery maples maintained Brix levels better than sugar maples albeit not quite as sweet overall as sugar maples.

12) Mystery maples lost ground to sugar maples in terms of sap production volume as the season got later and later.

13) Surprised yet?  Maybe not.  But consider this – the best half of our mystery maples OUTPERFORMED the worst half of our sugar maples in terms of syrup production potential.  Would that also hold true for 2022?

14) Fast forward 11 months to yet another choppy, wild, and erratic 2022 sap season.  When will we have another “normal” sap season?

15) Note to self, might have to add another 10 degrees to y-axis of Sap Run graph in 2023.  I surely hope not!!

16) More in line with studies elsewhere, our 2022 mystery maple trial trees matched or outpaced sugar maple’s sap volume production up until the final sap run of the year.

17) Brix consistently tracked 0.2-0.4 points below for mystery maples as compared to sugar maples.

18) Ultimately, we’re excited and hopeful for a “normal” 2023 season to collect data from a more representatively average season.

19) In the interim, both years suggest that mystery maples are not to be overlooked especially if you are an operator using reverse osmosis in your sugarhouse looking to expand your number of taps.

20) Stay tuned for 2023 – our 3rd year of ACER-funded research investigating alternative maple species production potential.

UVM Proctor Red Maple Research

There is plenty to learn from this video focused on Proctor’s red maple research.  How much sap is produced?  How sweet is the sap?  What sort of quality can be achieved with the syrup?  This research has a similar set of questions to the USDA ACER grant we are working on here in Ohio comparing sugar maples to the red x silver hybrids on The Ohio State University-Mansfield campus.

Time Lapse ACER Research

Watch this time lapse video of maple research taking place at the Ohio State Sugarbush located on the OSU Mansfield Campus.

Across 13 racks with 5, 6, or 7 canisters each, the OSU maple team emptied sap to monitor individual tree yield and sap sugar content…daily! The 75 research canisters will help us answer questions about how red x silver hybrid trees (Acer freemanii or “rilver” for short) compare to sugar maple production standards. The PVC canisters are a new design engineered by the team, and vacuum consistently achieved levels in the 22-25 pounds range. A drill pump mounted on a standard cordless drill boosted our sampling efficiency, and a digital Misco refractometer handled sugar readings.

While the data won’t be formally analyzed for a bit, we were surprised just how variable individual trees performed based on sap volume as well as sap sweetness. A couple trees achieved sugar content readings over 3 even at the end of the season. While other trees struggled to break 1.2 or 1.3% all season. For yield, 2-3 gallons a day was average for some trees. Normal for others amounted to just 1 or 2 quarts. The team is pulling down the research equipment now for off-season storage.

Stay tuned for updates.

Author: Gabe Karns, OSU Mansfield & SENR