I’d Tap That (Tree): Naturalist Notes
Maple sugaring season is upon us. We are spending our days tapping our sugar maple (Acer saccharum) trees to harvest sap that can be boiled down to syrup. That got me thinking, what other trees can you tap?
Let’s first look at what sap is. Every tree species produces sap. Sap is a watery solution of hormones, minerals, sugar, and other nutrients. Think of sap like the blood in our own bodies. The sap moves these nutrients to the parts of the plant that needs them.
The reason sugar maples are a favorite to tap is that they contain one of the highest sugar contents, about 2%. The higher sugar content along with certain amino acids and other compounds are what provide that unique maple syrup taste once it is boiled down. These trees also have a long tapping season, about 4-6 weeks depending on the weather, allowing a lot of sap to be collected. This is needed because it is about 40 gallons of sap to make 1 gallon of syrup. On average one tap hole can produce between 10-15 gallons of sap over the course of the season.
It's not just the sugar maples that can be tapped, most of the other maple species in Michigan can also be used to make maple syrup. Black Maple (Acer nigrum) is right behind sugar maples for sugar content in their sap. Silver maples (Acer saccharinum), red maples (Acer rubrum,) and box elders (Acer negundo) have a sugar content coming in around 1.7%, but these species produce more “sugar sand” during boiling. Sugar sands are natural sediments in maple syrup that clump together during the heating process. It will take about 60 gallons of sap to make 1 gallon of syrup for these other species of maple trees.
While North America has a rich history of maple tapping, in other parts of the world the Birch tree reigns supreme. The sap itself from the birch tree is sometimes called a springtime tonic, because of its minerals, enzymes, proteins, vitamins, antioxidants, and sugars. Birch juice, as it is called in Slavic regions, has a myriad of traditional medical uses from curing gout to scurvy to lung diseases. But this super drink is not very shelf stable and will start to ferment after 2-5 days in the refrigerator. Now after it ferments it can be used to make wine or birch beer. Also, this sap can be boiled down into syrup, but you will need a whopping 110 gallons of sap for 1 gallon of syrup. That is because it is only .8% -1.3% sugar content. The flavor of the syrup is said to combine flavors found in caramel, honey, and molasses, but with a spicy aftertaste. Not only do you need much more sap to make syrup, but you have a much shorter window where you can collect. Tapping season for birch trees is only 2-3 weeks. It can be hard to tell when to tap a birch tree, but the general rule of thumb is it normally coincides with when the first celandines or early daffodils are in flower. Just like with maple trees, you need to make sure you are picking a tree that is large enough to be tapped, at least 8 inches in diameter. Something else that is noted is that Birch trees are not as hardy as maple trees. Some studies have found that infection and wood decay had spread from more than half of the old tapping holes, and wounds caused by tapping birches consistently lead to dark staining in the wood. The different birch species that can be tapped are sweet birch (Betula lenta), paper birch (Betula papyrifera), and red birch (Betula fontinalis). I have quite a few birch trees on my property, it is now on my sap-bucket list to tap them so I can try their sap and syrup.
A relatively new phenomenon in the tapping world is walnut species, this includes black walnut (Juglans nigra) and butternut (Juglans cineria), both Michigan natives. There is still a lot of research being done on walnut tree tapping. From the research, it looks like tapping can start any time from late autumn to early spring, with the best time possibly being the first week of January. Though the season is longer, the flow is slower. They produce far less sap, only about 1/3 as much per tree as maples. The sugar content changes greatly over the course of the season. Ranging anywhere from 2% to 6 %. The sap-to-syrup ratio varies from the start of the season to the end of the season. The first batches are on par with maples at 40 gallons of sap to 1 gallon of syrup, then by the end of the season it is about 60 to 1. The taste is supposed to be uniquely smooth, light, and refreshing.
These are kind of like the big three in tree tapping for sap and syrup. There are over 27 different tree species that have reports on being tapped. One that caught my eye was Sycamore. It has a very low sugar content but is said to have a butterscotch flavor. Adding that to my sap-bucket list! Because all trees produce sap, they all have the potential of being tapped for sap and/or to make syrup from.
If you are planning on experimenting with tree tapping, a word of caution. There are some trees whose sap is toxic. Also, some trees might be very susceptible to disease if tapped. I would also stick to deciduous trees because on top of producing sap, pine trees also make a resin that is used in glue and turpentine. (Now some resins are used for chewing, but that is a whole other topic). But overall just do your research about the trees before you tap and consume anything.
Happy Tapping Season!
Submitted by: Cathy Wesley, naturalist, March 2023