October 27, 2023
Anne and I aren’t the only ones preparing for the coming winter - our trees have been thinking about it for weeks. Sugar Maples use the final sunny days of fall to manufacture and store the carbohydrates they’ll need in early spring. Those carbs will also provide us with the sap we’ll boil to make maple syrup next year.
As trees sense the colder weather and shorter days of fall, they begin to cut off circulation to their leaves and the chlorophyl, which gives the leaf its green coloring, starts to break down. The yellows and golds of autumn are the true colors of the leaves but as long as they are actively making use of the sun’s light to create energy, the green chlorophyll masks the color. In Sugar Maples, as the green fades, the sugary carbohydrates that get trapped in the leaves create anthocyanin pigments which color the leaves various shades of red.
All the rain we have had the last couple of months, though, has allowed the Anthracnose fungus to thrive. The pathogen causes Maple leaves to develop brown spots and fall off early. The fungus is usually most prevalent in spring when trees can easily recover from any leaf loss. Damp spring weather normally gives way to dry summer heat and the fungus is kept in check, giving the tree plenty of time to regrow its leaves. This year though, we’ve had such a damp fall that the fungus continued to bloom throughout the summer and fall and the leaf loss happened too late in the season for many trees to regrow their leaves. This is part of the reason why our foliage has been so muted this fall - we are missing a lot of the sugary red from the maples.
Last year, Anne and I had the worst maple sugaring season we’ve ever had, and I fear next spring will be the same. Time will tell if this warm wet fall has been the result of weather patterns in the Pacific or is in fact the new normal. Our golden Fall has been breathtakingly gorgeous, but I’m a little bit worried about our trees.