In order to make maple syrup, you have to tape maple trees, but have you ever wondered, why do we get maple sap from maple trees?  How did someone figure out that something so delicious was hiding inside a tree?  And where did the maple sap come from anyway?

We Collect Sap Because…Sap Is Delicious!

Have you ever tasted maple sap?  You will be disappointed if you plan on tasting syrup, but it still has a slightly sweet taste that you can sense with your taste buds.   Try it out at home with this taste test activity.

Step 1: Prepare your maple sap.

There are two ways to do this. Option 1: Tap a maple tree and collect sap. You can learn more about how to do this here.  Option 2: May your own sap solution that has the same amount of sweetness as maple sap.  Here’s the recipe:

• Add 2 teaspoons of sugar to 1 cup of water and stir until it dissolves.  It may help to use hot water or to heat the mixture (with the help of a grown-up).

Step 2: Prepare your taste test.

You will taste test your sap and compare it to water.  Pour yourself a small glass of water and a small glass of sap.  You only need about 1 tablespoon of liquid to drink, so you should have plenty of sap solution for many people to try.

Step 3: Make a data table to record the things you notice.

First, think about what you might want to notice and remember about your test.  You might notice the color, smell, and taste of the sap and water.  You could even make a prediction.  Do you think they will smell and taste the same?

Next, draw up a data table that will help you keep track of your results. Here is an example:

Step 4: Put your senses to the test.

Start by looking at both of your samples.  What color are they?  Write this in your data table.

Next, smell the water sample. Does it have a smell? Record the smell in your data table.  It’s okay to say “no smell” if you do not smell anything.  Now, smell the sap sample and record this smell in your data table.

Next, taste the water sample.  What does it taste like? Record this in the data table.

Finally, taste the sap sample.  What does it taste like?  Is it the same or different from the water?  Record this in your data table. Did it taste like you were expecting it to?

Animals and Maple Sap

In the next chapter, you’ll learn why maple sap (or your sap solution) tastes so different than maple syrup.  However, you probably noticed that the sap also tastes different than water.  Indigenous Americans noticed this too, and they realized they could make a delicious treat from maple sap.  Many American Indian tribes have stories about animals helping people notice maple sap.

The Lenne Lenape people from what is now the eastern United States tell a story about a woodpecker:

Long ago, Sugar Maple, was suffering from an intense itching caused by beetles burrowing beneath his bark, but he could not scratch himself.  The itching became unbearable.  He could do nothing by himself to relieve his suffering.

So, he called out the the squirrels, porcupines, and beavers to help them, but they were busy.  Then, Sugar Maple called out to the birds, and Woodpecker said he could help. He worked very hard and was finally able to pick every pest from Sugar Maple’s bark, and his itching stopped. Sugar Maple thanked Woodpecker for his help and Woodpecker thanked Sugar Maple for the good meal.

Many years later, Woodpecker came to Sugar Maple.  After a long period without rain, Woodpecker was dying of thirst and asked Sugar Maple for help.  Remembering that Woodpecker had helped him in the past, he told him, “Go to my trunk and drill some holes and they will fill with sap.”

Woodpecker drank until he was no longer thirsty, Woodpeckers have been drinking from trees ever since.  It was from the Woodpecker that the Lenne Lenape learned that trees give sap and can be tapped.^[1]

Indigenous people used traditional ecological knowledge and knowledge passed down from elders to understand how to collect and process sap from maple trees into sweet foods. Historically, families and communities would gather in the sugar bush and stay for several months to make maple syrup and maple sugar.  Many Ojibwe and Dakota people continue this tradition today, gathering with their families to make maple syrup and to celebrate their traditions ^[2]

Other tribes have shared stories about squirrels letting people know about

sap.  A scientist named Bernd Heinrich noticed something similar. He noticed that red squirrels would bite holes into maple trees. This made sap drip out of the trees.  The squirrels would not drink the sap right away.  Instead, they would come back later when some of the water had evaporated, making the sap sweeter.^[3]  At the Arboretum, squirrels like to eat sap too.  The often bite holes in our maple tubing and enjoy the sweet treat that drips from inside.

There is Sap to Collect Because…Trees Make Sap For Themselves.

A tree’s sap is kind of like your blood.  It flows through small tubes in the tree’s trunk and carries the things that the tree needs to survive.  These tubes are inside the bark of the tree, so to collect maple sap, you need to put a spile through the bark and into a tree’s sapwood.

The heartwood is the central part of the tree. This part of the tree is dead, but it is still very strong.  It supports the weight of the tree.

The sapwood carries water and minerals in hollow pipes. It is also known as the xylem.  This is where the maple sap flows.

The vascular cambium is the growing part of the trunk.  New cells form here.

The inner bark is also known as living phloem. It passes nutrients and other chemicals to the rest of the tree. These cells live for a short time before becoming part of the outer bark. Then, new phloem cells replace them.

The outer bark is also known as the periderm or cork. It protects tree by keeping it warm and dry.^[4]

Turning Sunlight into Sugar

Sugar is one part of a tree’s sap.  During the summer, trees make sugar in their leaves using the energy of the sun and carbon dioxide from the air.  This process is called photosynthesis. (Photosynthesis means “using light to put things together.”)  Once a tree has has made sugar, the sugar can move to different parts of the tree in the sap.

There are also other things in a tree’s sap like minerals, other nutrients, and the chemicals it makes to defend itself from diseases and bugs. These help the tree to grow and stay healthy.  They can also make the syrup we make from maple sap a healthier for humans than sugar.  The weather in the summer can change how much of these sugars, nutrients, and chemicals are in a tree’s sap.  Cooler July temperatures make sweeter sap the next March.^[5]

Can you make syrup from other kinds of trees?

All trees make sap, not just maples.  You can tap other kinds of trees and collect their sap to make syrup too.  Different trees will have different amounts of sugar, minerals, nutrients, and chemicals in them, so they will make sap that tastes different.

At the Arboretum we tap a few walnut and birch trees too. Birch syrup has a completely different flavor from maple sap. It has a flavor that some have compared to a caramel apple – sour and tart flavors mixed with sweetness. Other people think it tastes like a mix of molasses, balsamic vinegar, and raspberries. It tastes different than maple syrup because birch sap has less sugar and different chemicals in it than maple sap.^[6]

Not all trees have sap that runs in the spring time. You can tap a walnut, hickory, birch, or basswood tree and collect their sap. However, willow, aspen, elm, ash, and oak trees do not have sap that runs. ^[7]

We Can Collect Sap in March Because…Temperature Changes Make It Run.

How To Tap Your Own Maple Tree

1. Head outside to where you’ve added a spile to your maple tree (or to put one in now) with a thermometer and a stopwatch. You can use a phone for a stopwatch, but it’s best if you can take the temperature right where you are instead of using a weather app.
2. Hold the thermometer right next to the place where you’ve tapped your tree and record the temperature.  Make sure it is in the sun if your spile is in the sun.
3. Set your timer for 30 seconds. Count the number of drips from your spile before time is up. Record your data.
4. Enter your data in our survey form (if you’d like).  The form is linked below
5. Repeat at different times of day, different temperatures, different trees, and on shady or sunny days to see how your results compare.

Here are the results:

Maple Sap and Climate Change

Remember how I said that maple sap usually runs in March in Minnesota?  This is not always true. Maple trees do not have sap to collect every day of March.  Sometimes sap starts flowing earlier in February or it continues into April. It all depends on the weather. Our changing climate might make this difficult to predict in the future. It might also mean that Sugar maple trees no longer grow well in Minnesota.

What would a future without Sugar maple trees look like? Some experts suggest that Red maples grow better in warmer and changing climates.  Their sap tastes a little bit different because it has different chemicals and sugars in it.^[8]

The University of Massachusetts has a lot of great information and videos about maples and climate change from indigenous experts.  You can find this information at https://blogs.umass.edu/acernet/

Maple sap is kind of sweet, but maple syrup is even more delicious.  Now that you’ve learned more about why maple trees make sap, you’ll have an even greater appreciation for the maple sap you enjoy.  In the next section, you will learn about all of the hard work that people put into making maple syrup too!