For the past few mornings, I’ve seen something very interesting in a big hardwood tree in the backyard. (Note: The photos here were taken over the course of two or three different days.)
See those white things hanging from the tree?
Here's a closer look:
These are “sapsicles.” A sapsicle forms when sap freezes into an icicle as it drips from a branch of a tree.
There's clearly a little break or crack in the branch at that point; it might have happened during a high wind, or from the weight of snow, or from the actions of a woodpecker, or perhaps from the the weight of a squirrel that jumped on to that branch when it was frozen and brittle, such as during the really cold spell that we had some weeks ago.
When the sun warms the tree, the sap expands and rises through the trunk and branckes, and is pushed out wherever there is a crack or other opening. If the air temperature is below freezing, the sap will freeze.
The sapsicles can get fairly long; the one shown here was almost two feet long:
Sapsicles are evidence that the sap is rising, and that's a sure sign of spring.
Next time the sun is warm and the air is cold, look for sapsicles in the hardwood trees.
Another sign of spring, also dependent on rising sap, is of course, the tapping of sugar maple trees. When I was visiting K yesterday, we took a little drive around the farms and fields. We noted that many maple trees have been tapped already. It was nice to see the old-fashioned galvanized buckets instead of the plastic line system that uses no buckets at all.
From the Journal of Henry David Thoreau, February 23, 1857:
I have seen the signs of spring. I have seen a frog swiftly sinking in a pool, or where he dimpled the surface as he leapt in. I have seen the brilliant spotted tortoises stirring at the bottom of the ditches. I have seen the clear sap trickling from the red maple.