Why does the snow seem to melt first around the trunks of trees?

After all, the canopy shadow in the woods should theoretically keep everything cold longer, shouldn’t it? The sun doesn’t get down there as much as in fields.

But you can’t help noticing in the old snow those bare-earth circles around the base of trees, whether young or old, in our woods along the side of roads. What’s going on there?

My first thought was: Could trees possibly be warm-blooded (warm-sapped)?

Stop the presses! Ever since I was a kid watching a TV “science special” that suggested trees and other plants feel pain, I have felt an affinity for these sturdy, dignified companions. It caused me immediate guilt for carving the initials of the girl down the street on the backyard maple. I could even hear the groans.

Thinking that now I might have discovered a new reason for kinship with trees, I did the modern thing. I consulted Google. Why does snow seem to melt first around trees? I wrote.

You’re not going to believe this: I got 475,000 results. Apparently, others wondered, too.

I didn’t read all of the answers, of course, but I scanned many. Surprisingly, despite our advanced scientific knowledge in the 21st Century, even expert opinions differed on the question

The most fun replies came from amateurs like me. Yahoo Answers has a website for the likes of us. Here’s a sampling of their answers:

“Trees save energy from the sun and give it off as heat.”

“Water drips from the tree branches.”

“The branches overhead make it so there is less snow to begin with. Next to the tree there is a good water supply and this could make the ground slightly more moist which could cause the snow to melt faster.”

“Trees cut the wind and force turbulent air around the tree; warm or cold air carries the moisture away.”

“Cause guys usually pee behind a tree.”

“I don’t know. I live in Florida.”

Interestingly, none that I could find agreed with my idea that trees contain their own warmth.

So, back to the experts Unbelievably, I could find no definitive answer to what I regard as a very basic question. I mean we’re not talking Big Bang here.

The preferred explanation is that dark tree bark absorbs the heat of the sun and thus thaws the snow around the base. Others said water drips down the tree during thaws and thus melts the snow around the base. Very reasonable.

But then you have the it-all-depends crowd that just confuses the situation, such as the following from a study by the University of Washington (State): “… trees in warmer, maritime forests radiate heat in the form of long-wave radiation to a greater degree than the sky does. Heat radiating from the trees contributes to snow melting under the canopy first.” Useless.

Finally, I found a 2011 article in the New York Times that posed the question to the science director of the Brooklyn Botanical Garden. Now, we were getting somewhere. Dr. Susan Pell cited the prevalent opinion about heat-absorbing tree bark, and then the article added:

“Another possibility,” she said, “is that many plants — in the Northeast, especially those that bloom early in the spring — generate their own heat for various reasons. Some emerging herbaceous plants, like those growing from bulbs, produce heat to melt snow in order to more easily break through it in the springtime,” she said. “This is most famously true of skunk cabbage …”

Skunk cabbage? I’m talking about maple, oak, hickory, ash, beech and birch, not swamp plants.

I give up. You’re just going to have to accept my theory: Trees give off their own body heat. Period.

– GAK 03/21/14