Sycamore Syrup: Generating Farm Income and Protecting Riparian Zones in West Virginia

Year 1: (2021 - 2022 sapflow season) 

The project began in late summer with the development of a detailed work plan for the fall through sap season. These plans included scheduling wood lot assessments, ordering equipment for each partner site and the University research site. 

Six sycamore trees were tapped in November 2021 at the Future Generations University Sycamore Research Site and collection was set up using sap bags (rather than collection tubing lines). There were several small sap runs when the temperatures fluctuated appropriately, however the sugar content in the sap collected was negligible. Weather data also shows that it was an especially warm fall and early winter which may have impacted both the quantity of sap collected in the limited runs as well as any potential for measurable sugar content. 

In late October, the specific sycamore stand analysis (collecting DBH, GPS Location, etc) for each tree to be tapped. All of the required equipment, including site-specific needs such as solar power for pump setups, was ordered and during the months of November and December, equipment was delivered and set up with partner farmers. 

With the limited sap flow in the fall season, supported by previous research looking at the internal pressure generated by a sycamore, and the lower to negligible sugar content, it appears that a fall season would not be worth pursuing for sycamore. This conclusion is also supported by work done in the maple season as well, indicating that trying for a fall season is not necessarily beneficial to a sugaring operation because of lower production numbers and increased tree damage (van den Berg, 2020).

Year 2: 2022 Sap Flow Season

Production Data:

The first season of this project was focusing on the feasibility of the small vacuum system for sycamore, as well as testing the feasibility of producers making both maple syrup and sycamore syrup simultaneously. The data points collected were focused predominantly on sap production and how sap production responds to temperature fluctuations. Specifically, we asked producers to record, sap volume, sugar content, vacuum readings on their pump controllers each day. The weather stations at each site recorded temperature data over the course of the season. Some of this data was also augmented with information from local weather stations accessed through Weather Underground (wunderground.com) because of technical difficulties with the weather stations.

The first season of data collection focused on looking for indicators of sap flow and developing baseline data for each research site. Overall, there are few definitive conclusions we can draw from this initial data, but it is good descriptive data to look at what commercial sycamore syrup production entails. Future Generations University never received data from the Noonan research site, and the partner farmer stopped all contact.

Table 1. Sap production at each site compared to the number of taps and basal area across the research sites.

As indicated in Table 1, Hillsboro Maple Works greatly out performed both the FGU Research Site and Ronk Family Farm in sap production even when analyzed by tap. Looking at the next column, the sap production data has been analyzed to account for tree size discrepancies across the research sites using basal area. Tree size is a known indicator of potential sap output in maple (Isslehardt, et al., 2018). Focusing specifically on Hillsboro Maple Works and Ronk Family Farm, sap production per foot of basal area is far closer than sap production per tap. Indicating that the trees at each site were producing similarly, but the trees at Hillsboro were much larger than the trees at Ronk, accounting for more than double the sap production per tap. The FGU research site still lagged behind in sap production, which could be attributed to climatic or site specific factors. The FGU research site also had a shorter season than the Hillsboro and Ronk sites.

Table 2. Other production data from the three research sites.

Looking at possible production discrepancies between the FGU research site and the other two reporting sites, it is important to analyze the vacuum system. Higher vacuum is directly correlated to greater sap production in maple (UVM Proctor, 2019). However, as seen in Table 2, there is not a significant difference in the average vacuum between the Hillsboro site and the FGU site over the course of the season, ruling this out as a possible explanation. This leads the researchers to believe that it was an unknown site difference or local weather difference that accounts for the difference in sap production at the FGU research site. The reason Ronk Family Farm is being excluded from this data is because only one vacuum reading was recorded, making it an unreliable data point because the other two research sites saw fluctuations in vacuum over the course of the season. Fluctuations in vacuum, especially with a diaphragm pump, are to be expected over the season.

Another important factor in syrup production is the sugar content of the sap, which is measured in Brix. From preliminary sycamore studies, it is known that the average brix for sycamore sap is lower than that of maple. This factors into the feasibility of sycamore syrup production because it determines the amount of sap it takes to make one gallon of syrup and has already been accounted for in the research design by providing RO buckets to all sites. The FGU Research Site had higher average Brix than the other two sites, which can be explained by tree and site differences. Genetic differences in individual trees, their canopy health and size, exposure to sun, and length of growing season can all cause Brix to be higher in certain trees even if they are of the same species (Taylor, 1956).

 Using the average Brix from each site and the Jones Rule of 86, the amount of syrup that each site could have produced was calculated. The FGU research team looked at potential syrup production to standardize for operator error and inherit volume loss in syrup processing. For confirmation that the calculations were accurate, Hillsboro Maple Works reported making 3 gallons and the FGU research site reported making 0.5 gallons of syrup. It is important to note that Ronk Family Farm was unable to make any sycamore syrup. Ronk Family Farm is at a lower altitude and further south than the other two sites and had on average warmer daily temperatures in 2022. In warm weather, sap spoils quickly, and Ronk Family Farms’ sap spoiled before they were able to process it. This does point to the possible added labor ask of processing both sycamore and maple sap at the same time. In terms of informing sycamore syrup production potential, the amount of syrup per tap was analyzed, and both Ronk Family Farms and FGU research site produced 0.02 gallons of syrup per tap and Hillsboro Maple Works produced 0.05 gallons of syrup per tap.

Table 3. Cumulative data from the three research sites from 2022.

It is important to note that these averages are only from a single season and three sites. However, these numbers begin to be a possible predictor for the production potential of a sycamore sugar bush. For example, from this data, a 100-tap sycamore sugarbush would be expected to produce approximately 3 gallons of syrup. Combine this information with the best estimates for the market value of sycamore syrup, approximately $325.00 bulk, it's predicted that a 100-tap operation would make about $975.00 worth of syrup.

Weather:

Using the weather stations purchased for the project, temperature data was analyzed for each of the three sites to look at climatic factors that may impact sycamore sap flow. As in maple, sycamore relies on freezing temperatures at night and warm during the day to trigger a sap flow event. A few separate metrics were looked at to see if weather accounted for some of the differences in sap flow between the research sites. Looking at the data presented in Table 4, it becomes apparent that a possible explanation for the Hillsboro site out producing the FGU and Ronk sites is the fact that it had better sap flow weather.

Table 4. Run days and average temperatures for each site. Note: “Possible Run Days” indicate days where the maximum temperature was above freezing and the minimum temperature was below freezing. “Ideal Run Days” indicate days where the minimum temperature was below 25 ºF and the maximum temperature was above 40 ºF.

ONE21-404 Data-tables
Figure 1. Daily temperature fluctuation paired with sap flow in gallons of sap per tap over the course of the season at FGU Research Site.
Figure 2. Daily temperature fluctuation paired with sap flow in gallons of sap per tap over the course of the season at Hillsboro Maple Works.
Figure 3. Daily temperature fluctuation paired with sap flow in gallons of sap per tap over the course of the season at Ronk Family Farm.

The figures above illustrate that Table 4 showed that Hillsboro Maple Works had more runs than both the FGU site and Ronk Family Farms. Looking beyond just sap flow days, there is a trend of more gallons of sap per tap after extended cold spells. Though a similar statement could be made about maple sap, this is partnered with observations from the partner farmers that sycamore trees appeared to prefer colder temperatures than maples, and the suggestion to tap earlier the following year.

Feasibility:

Two of the research sites were able to make syrup in the first season as mentioned previously. This allowed for some preliminary observations about the possibility of a sycamore syrup market. Thus far, all data used to inform about sycamore syrup sales has come from research on the newly emerging walnut syrup industry and the birch syrup industry. This was the first opportunity to see any true consumer data points. The FGU research site does not commercially sell any products, but the syrup produced at the research site was used to drum up interest about sycamore syrup through tasting events and small bottles sent to specific groups. It was also used to experiment with a new product called “Maplemore,” which is a mixture of maple syrup and sycamore syrup. This mirrors what walnut syrup producers are doing to bring down the price point of their walnut syrup and increase the price point of their maple syrup.

Hillsboro Maple Works did sell some of their sycamore syrup commercially, finding that they had more demand than they had product at their initial price point. They also experimented with making sycamore syrup straws. These small, individually packaged sample straws seemed to be a hit and sold well for them. With the initial success of sycamore sales and the initial taste testing of both sycamore syrup and “maplemore,” it looks promising that sycamore syrup could have similar success as the other alternative syrups.

Gravity and Tap Height:

In the first full season of this study, two research sites looked at height of tapping and the viability of gravity collection systems for sycamore. Gravity collection systems in maple hold an important role for small scale producers because it is cheaper and easier to maintain than a vacuum system. In early experimental tappings of sycamore, no significant sap flow was observed in buckets, however one of the partner farmers, who had some previous experience tapping sycamores, said that when he tapped lower on the tree, he saw significant sap flow into a bucket. In field trials, the FGU research site and Hillsboro Maple tapped five sycamores each on bags. Each tree had two taps, one in the normal maple tapping zone and one lower on the tree. Neither site saw any significant sap flow into the bags, resulting in no data. However, the lack of data allows for the conclusion that commercial sycamore syrup production requires a vacuum system to be viable.

Year 3:

Production Data:

Moving into the third year of the study, the second full sap season, the FGU research team held a meeting with the partner farmers to discuss what areas of the study needed to be looked into further or altered and what research they were interested in. All research sites voiced their desire to tap earlier, as they had noticed that sycamores seemed to produce better in colder weather. It was also decided that it was important to continue collecting the same data as last year with the same collection methods because the yield data from the three sites varied greatly. Again, we asked producers to record, sap volume, sugar content, vacuum readings on their pump controllers each day. The weather stations at each site recorded temperature data over the course of the season. Some of this data was also augmented with information from local weather stations accessed through Weather Underground (wunderground.com) because of technical difficulties with the weather stations.

Table 5. Sap production at each site compared to the number of taps and basal area across the research sites.

The first thing of interest is that the Ronk Family Fam research site did not see any sap over the course of the season (Table 6). Though some sap may have run, it was never enough to collect any data off of, leaving us with little information in terms of sap yield. The lack of data from the Ronk family research site and its greater implications will be discussed later. Hillsboro Maple Works had a less productive year than they had in 2022, producing 134 gallons of sap less. Meanwhile, The FGU research site produced 61.3 gallons of sap more, almost doubling last years runs. Even though the FGU site greatly increased their sap yield, and Hillsboro saw a reduction in sap output, the trees at both sites were producing about the same amount of sap per foot of basal area.

 It is important to note that the FGU site was retapped part way through the season to test experimental taps, which could have accounted for the bumper crop. 53.75 gallons of sap were collected after they were retapped. Retapping has become popular amongst southern maple syrup producers because of the possibility of an extended season. For the sake of looking at season long data, the sap collected before and after the retapping will be included in the descriptive statistics.

Table 6. Other production data from the three research sites.

Continuing to look at other descriptive statistics about the season, the FGU pulled less vacuum on the system over the course of the season, explained by a few serious leaks were found in the system throughout the season. Hillsboro Maple Works also saw a slight decline in vacuum, which is to be expected in a systems second year. Hillsboro Maple Works and the FGU research site both saw a decline in sap sugar content, which could be caused by a variety of factors described earlier (Taylor, 1956). Using the Jones Rule of 86, possible syrup production was calculated and syrup per tap was estimated to be the same between the two research sites. Though this number is influenced by so many possible factors, it is of note because this may indicate that this study has been able to develop some predictive data.

Table 7. Cumulative data from the three research sites from 2022 and 20233.

Looking at averages of the production data over the two seasons supports that this study did produce predictive data. Though the Brix varied some, based on this data, it can be assumed that on average a sycamore tap will produce around 5.7 gallons of sap, at approximately 0.5 Brix to make 0.03 gallons of syrup over the course of the season, leading to roughly $1,000.00 worth of product per 100 taps. It is worth noting that this is all still heavily influenced both by local climate and yearly weather patterns.

Weather:

Table 8. Run days and average temperatures for each site. Note: “Possible Run Days” indicate days where the maximum temperature was above freezing and the minimum temperature was below freezing. “Ideal Run Days” indicate days where the minimum temperature was below 25 ºF and the maximum temperature was above 40 ºF.

To try to determine why the FGU site had a much better year, while the other two sites had worse years, it is important to look at the weather data. The FGU research site had a much better, longer season with more possible run days and ideal run days, as well as colder temperatures overall. These better climatic conditions, longer season, and the retap could explain the large jump in production at the FGU research site. In Hillsboro, the season looked about the same as the previous year when examining run days and the average high of each day. The main difference is it was not as cold. The average low was three degrees higher than in 2022.

As mentioned previously, Ronk Family Farms did not produce any usable sap data. As reported by the partner farmer, it never ran enough to collect data. He also struggled with the small diaphragm pump as its smaller, cheaper parts did not hold up well in the off season. It was also not a particularly good maple year for him either, indicating that there may be some climactic cause for the lack of sap flow on top of the collection system issues. Looking at possible run days and ideal run days, his season looked about similar or slightly better than 2022. The average high was also similar to 2022. The main difference was the average low was 2 degrees higher than the previous year. With both Ronk Family Farm  and Hillsboro Maple Works having worse years and higher average lows, it may indicate that sycamore do prefer colder temperatures during sap season. Figure 1 and 2 analyze sap flow along with the daily maximum and minimum temperatures. As in 2022, it appears that higher production follows colder temperatures.

ONE21-404 Data-tables
Figure 4. Daily temperature fluctuation paired with sap flow in gallons of sap per tap over the course of the season at FGU Research Site.
Figure 5. Daily temperature fluctuation paired with sap flow in gallons of sap per tap over the course of the season at Hillsboro Maple Works.

Feasibility:

Feedback was taken from all research sites on the feasibility of making both maple and sycamore syrup. In the first season, Hillsboro Maple Works was successful at making a usable amount of sycamore syrup, and was positive about the experience even though it did add a significant amount of extra work. In the second season, they were less positive about the experience because they felt that the amount of syrup made was not worth the extra effort. However, they have shown interest in trying for another season, but are wary of being able to sustain the added labor if the syrup yield is not enough.

The Ronk Family Farm experienced more technical difficulties than the other site. Some of the difficulties were due to the location of the pump set up and lack of sun exposure for the solar array, which could be improved had the study not needed to order the same equipment for each site. In the future the research site can change the collection system as needed to work with their site specific requirements. Another issue seen was the same as Hillsboro which was the amount of extra time it took. One particular note is that at Ronk Family Farm the sycamore were separate from the maple trees and where sap was processed was separate as well, which seemed to add difficulty to juggling the two. Despite the difficulty, the Ronk Family Farm is still interested in trying to produce sycamore syrup because they have seen an increase in interest in their operation with the newest product.

Lastly, the FGU research site only produced sycamore syrup, negating most of the issues the other two sites saw. However, they continued to work on the blended syrup “maplemore,” which may hold the key to making both. The “maplemore” that was finalized as the best ratio is approximately 20% sycamore syrup and 80% maple syrup. This means that a single gallon of sycamore syrup can make a lot of maplemore. Why this could be the key to success is because a maple producer could tap just a few sycamore trees and make enough product to have a substantial stock of maplemore, which could make the added time worth it.

Vacuum:

Though this study initially wanted to look at what differing levels of vacuum would do to sycamore sap production, it quickly became clear that there was not enough baseline data to adequately assess the effects of medium to low vacuum. What this study was successful in doing is establishing a baseline for sycamore tree sap production under low to medium vacuum. This baseline can now be used to assess the possible production potential of sycamore sugarbushes and be used as a comparison point when other collection systems are tried. If this study had attempted to fluctuate vacuum throughout the season it would have not gathered enough definitive data to draw any conclusions from. However, it can now be confidently said that a sycamore tap on medium to low vacuum will produce approximately 5.7 gallons of sap per season, while a sycamore with no vacuum will not produce any.

Alternative Taps:

An experimental tap was used at the Future Generations University research site when it was retapped. The tap is designed to seat less deeply in the tap hole leading to higher sap production (Perkins, et. al., 2019). Looking at the data, the traditional maple tap did collect more sap than the experimental tap, but it was also in the tree longer (Table 9). The traditional maple taps were in the trees for thirty four days before they were retapped. The experimental taps collected sap for twenty days until the season was over. Looking at gallons of sap per day, it does appear that the experimental tap outperforms the traditional tap. It is worth noting that some of this spike in productivity could be attributed to the freshening of tap holes mid season. Fresh sap wood will produce more sap than wood that has been exposed to air for a few weeks. Another point of interest is the average vacuum for the line was 1inHg higher with the experimental taps than with the traditional maple tap, which may indicate that they seal better in the sycamore tree.

At the Ronk Family Farm research site, 5/16ths v. 7/16ths taps were tested using vacuum chambers for sap collection. However, due to the over all poor season this research site had no reportable data.

Table 9. Production data on traditional maple tap v. experimental maple tap in sycamore.

Isselhardt, M., Perkins, T., & van den Berg, A. (2018). Tree Size and Maple Production: Forest

Science Theme. NESAF News Quarterly, 79(2), 5-6. https://mapleresearch.org/pub/treesize-2/

Perkins, T. D., Bosely, W., & van den Berg, A. (2019, September 19). The Goldilocks Touch:

Overdriving spouts reduces sap yield. The Maple News. https://mapleresearch.org/pub/overdrive2020/

Taylor, F. H. (1956). Variation in Sugar Content of Maple Sap. Agricultural Experiment Station

University of Vermont and State Agricultural College Bulletin, 587, 3-39. https://mapleresearch.org/pub/variationsugar/

UVM Proctor Maple Research Center. (2019, September 19). Vacuum and Yield in Maple

Production [Video]. Youtube. https://www.youtube.com/watch?v=XxC0JVsNOyc

Van den Berg, A. K. (2020, October 3). Researches downplay fall tapping: Experts ‘Probably not

worthwhile.’ The Maple News. https://mapleresearch.org/pub/mn2020fall/