By Gary Salmon
I have the luxury of having a window just above the sight line of my computer. It is my icicle monitor and I have been waiting for it to change structure now for about a month or more. I like icicles. They look nice in the cold reminding me when to turn the furnace up or shovel snow off. But what I like most about them this time of year is the dripping. Drop by drop they shrink and remind me of what is just round the corner – sugaring season.
It has taken a fall and most of a winter to ready a sugar maple (or any maple) for sap flow. Last summer’s growing season left the roots full of starch and ready to transfer that energy once the buds demand it in spring. Roots have been largely dormant layered securely under a blanket of snow although, if soils do not freeze completely, some root activity does occur even during the bleak midwinter. All trees including maples insure that the physical living cells within the above ground portion do not freeze solid and rupture during our winters. They do this by transferring water from inside living wood cells to between the wood cells, making the actual cell wall more flexible, and changing the chemistry of the water stored in trees to make it more impervious to cold.
So what has this to do with icicles? It takes cool nights and warm days to melt icicles and inspire a maple to move sap. The stored root starch is converted to sugars and the movement of sap is, upward not downward, via the xylem.
Once again, the design system of a healthy maple tree is flawless in that the moving sap is in the outside wood of the tree allowing a maple tap about 3” deep to easily access what will become a whole host of maple flavored products.
So while steam from a sugar house is a sure sign sugaring has started, the first sign of this potential is the icicles melting. A sure sign that the season has ended is long after the icicles have departed and the tree buds have begun to swell in preparation for producing leaves. This creates a colored and poorly flavored sap and a mosaic of tree bud colors on our hillsides as the various species all become green with leaves.
As I peek above my computer screen it does not appear that today is going to encourage the icicles to drip, drip, drip. But an entire industry is waiting for just that to happen. And it will be soon.