Explore January: Sweet and Chilly - Syrups and Sugary Veggies Participants are given the chance to taste the difference between real and artificial syrup. This is an opportunity to understand the simplicity and superiority of pure maple syrup and to explore other syrups that are lesser known. Syrups are derived from tree produced naturally within trees, but these plants aren’t the only ones that get sweeter as the temperature gets chillier!

All trees and many other plants produce sap - it is universally used as a transport system within their entire structure, much like the blood in an animal’s body. Consisting mostly of water, the sap flows throughout the plant through tubes called xylem and phloem and carries nutrients and waste. Perhaps the most famous sap is that of the sugar maple tree (Acer saccharum) which is the only ingredient found in pure maple syrup. This sap does what all sap does, but it does it with a sweeter flair because it happens to range between 1- Image via Wikipedia 5% sugar content.1 What is this sugar? It is as simple as sugar can get - glucose! Through photosynthesis, plants absorb sunlight and use that along with carbon dioxide and water absorbed from both the air and soil to create energy-dense glucose molecules that are used by all the plant’s cells for basic metabolic processes. Glucose is water soluble so in a tree it is easily transported by sap, but it is also important to have stores of this energy source for when photosynthesis is no longer possible, such as during the cold winter months when most plants lose their leaves. To do this, many plants convert their glucose molecules into starch granules and then store these within Starch granules in a potato. their ; starch is not water-soluble, so they tend to stay right Image via Wikipedia where the plant puts them.

This fun video from University of California Los Angeles Image by Sarmis explains all about sweet adaptations! We already mentioned the sweet sap from the sugar maple tree, but there are many other trees that produce sap that contains enough sugar content to be converted into a delicious food, such as trees (yes, the flavor of birch beer!) and hickory trees. And they are not alone, but their fellow sweet plants might surprise you! Have you ever bitten into a carrot and found it sweeter than you remember carrots being? How about beets or turnips? These root vegetables (which you can learn more about in

1 https://www.uvm.edu/~uvmaple/sapsugarcontentvariation.pdf

1 the I Spy the Root of it All video lesson and accompanying activities) are designed to be centers of energy storage for plants, which means they are full of glucose and starch. The amount of sugar within these roots vary with the temperatures surrounding the plant, the most important of which is the cold; after the first frost of the season, these plants kick into preparation mode and begin packing their roots with these energy sources, thus resulting in sweeter food for you and whatever animals may munch on them in the wild!

The cold is also vital for trees, such as the Sugar Maple, because it is important that they experience a fluctuation in temperature from just below freezing at night to just above freezing during the day. This change in temperature causes a change in pressure within the trunk of the trees so that during the night time the sap and sugars are held tight within the roots system beneath the soil, but that pressure releases during the warmer daytime temperatures and causes the sap to flow freely. This pumping action allows us to tap the trees and collect the sap much more easily than trying to do so while it is barely flowing. Unfortunately, due to the warming global climate, this fluctuation is in jeopardy, and without these regular cycle of temperatures trees such as the sugar maple produce less sap, which presents dangers for their survival and for the survival of the animals that rely on them for food and shelter. According to the Proctor Maple Research Center at the University of Vermont, “the maple sugaring season on average begins 8.3 days earlier and ends 11.6 days earlier than it did just 50 years ago”2 (source) Though it may just seem like a threat to maple syrup supplies, the dangers posed by the current climate crisis are so much more than that! These sugary sweet plants are just one aspect of the natural world that is relying on us to help reverse the damage done.

According to the USDA, this is the projected number of maple tree taps required to produce just the amount of sap produced in 2012 if Climate Change persists! (source)

Check out the following video from the Proctor Maple Research Center about how researchers are studying the possibilities of tapping into birch trees in much the same way that they do maple trees, and then challenge yourself to answer the questions afterwards! You can find some of the answers on the following page.

2 https://www.uvm.edu/cals/proctor-maple-research-center

2 Fill out this Venn Diagram with the similarities and differences between the production of maple syrup and the production of .

1. When do birch trees begin to “run” or produce more sap, compared to the usual sugar maple tree?

2. What are the two important values that the researchers are recording every day while tapping these birch trees? Why are these numbers important to the research in the first place?

3. What is the main difference between the sap flow mechanisms of maple trees and birch trees?

4. How does pressurization determines how maples and can each react to a changing climate?

5. How high can the pressure within a birch tree’s trunk be? What don’t the researchers know about the tree trunk’s pressure capabilities?

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Answer Key Venn Diagram: Similarities include: Both are derived from trees, both are sap, both are boiled down to produce a thicker and sugary syrup, the syrups are about the same texture.

Differences include: Tree species are different, maple sap is on average 2% sugar while birch is about 1% or less, birch is darker than maple syrup.

Question 1: Birch trees tend to produce more sap after sugar maples have slowed down production.

Question 2: Researchers are studying the volume of sap produced and sap sugar content. They can understand the average amount of sap needed to collect and boil down to make syrup like maple syrup.

Question 3: Maple trees have a pressure system in their trunks that moves the sap up and down, but a birch tree’s pressure system starts in their roots.

Question 4: Depending on the change in air temperature vs. the change in soil temperature, the trees may experience a different level of change in their habitat. If the air is experiencing more of an erratic change while the soil remains slightly more stable, then the birch trees may not be as affected.

Question 5: 30 psi (pounds per square inch) and researchers are not sure how high or low the pressure within a tapped trunk can be, and this is important to understand how collection can occur.

Extensions Climate Change Consider the larger picture of climate change beginning with one sugar maple tree and expanding to a global view of food webs and the timing necessary for organisms to access various natural resources.

How it aligns to your lessons… New Jersey is the first state in the US to mandate a K-12 climate change curriculum in public schools. As stated in the NJDOE announcement: These standards truly represent a foundation from which districts will build coherent curriculum and instruction that prepares each New Jersey student with the knowledge and skills to succeed in our rapidly changing world. They will put New Jersey again at the forefront of national education by including the following:

Climate Change across all content areas, leveraging the passion students have shown for this critical issue and providing them opportunities to develop a deep understanding of the science behind the changes and to explore the solutions our world desperately needs.

Data For all learners, lessons that incorporate record keeping, data, graphs/charts and opportunities to analyze data to draw conclusions are important to most content areas including math, science, PE/Health, social studies, as well as others. To do so using information found in this article: Create a chart that includes the favorite fruits and vegetables of each student. Analyze the data to determine if there are trends and if these foods are those with the most sugar content. For more environmental education and interdisciplinary ideas contact Kate Reilly, Manager of Education, Duke Farms. [email protected].

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