How Does Climate Change Affect Maple Trees?

The maple leaf is synonymous with Canada, but the syrup which emanates from the tree is also an icon of the north eastern United States. In fact, around 50 years ago, 80% of the world’s maple syrup came from the US with much of it originating in New England with the remaining 20% from Canada — today, those roles are reversed.

Scientists at the University of Massachusetts believe the role reversal is down to climate change and that if the temperature of the planet continues to rise, maple trees (and the highly lucrative maple syrup industry that comes with them) could be eradicated from the US entirely.

An Exact Science of Nature

The production of maple syrup is a highly selective process which only occurs in certain climates and ecosystems. It’s entirely dependent on a rigid cycle of freezing and thawing which can only occur during very cold nights and mild days. When sub-zero temperatures set in during the wee hours, the sap is frozen in the tree’s roots. Then, as the temperature rises through the day, the sap creeps back through the branches of the tree and can be harvested by tapping one of its limbs. This occurs when temperatures reach between 4°C and 5°C.

However, due to the effects of global warming and climate change, harvesters have been forced into commencing their tapping earlier and earlier in the calendar year to take advantage of the cold temperatures while they last. This has resulted in a lower yield of syrup from the trees and a diminishing supply in the United States. The future of the maple syrup industry in the United States could have an expiration date of as early as 2100.

Chromatography Teaches Us More

The study is the product of a $150,000 grant into researching how exactly climate change has affected maple trees over time – and how it will continue to do so in the future. Syrup is mainly made up of sugar and water but also contains phytochemicals, which are the key to giving it its distinctive flavour.

Using high performance liquid chromatography (HPLC) to analyse trees tapped at various sites around North America, the team hope to understand how changing temperatures have affected syrup quality and composition. Its main aim, according to plant ecologist Kristina Stinson, is to “get a handle on how much variation there is in this secondary chemistry, the different concentrations of phytochemicals and the relationship to syrup quality in sugar and red maples across the landscape.”

It’s not the first time that chromatography has been used to analyse phytochemicals. As recently as 2014, the technique was used to investigate why candy cap mushrooms taste like the syrup and this article, Extracts of the Chinese Herbal Remedy Gymnema sylvestre Inhibit the Sodium-Dependent Glucose Transporter 1, looks at HPLC use in Chinese medicine.

Get your maple syrup stockpiled quick.

Image from Pixabay