March 6th, 2011 - Witchy Willows

Our snow has been 'come and go' lately, but I have been out snowshoeing in it as much as possible when it's around.
The other day we got a fresh six inches and I went over to 'Calhoun Park' in New Berlin, WI.
Calhoun is about the hilliest close wild place we have, which isn't saying all that much, this is southern Wisconsin and isn't exactly the Alps, but the place does have three sledding hills.
Anyway it's more than enough to get my heart rate pinned after about ten minutes when I'm wearing the big (28") Sherpas and using poles and wrist weights.
Here is a view from the upper trail. As you can see, the snow came from the north. Exclusively. A bit of a one-sided storm. 
This is not a black and white photograph by the way, that's the way it looked. 
Kind of the "bas-relief forest".
The next day much of the snow had melted off, but I put the Sherpas back on and walked out our patio and down along our little "creek".
It's been fun exploring along the creek, and this is about the only time of year it's easy to do. 
It gets really muddy and marshy in the spring, buggy in the summer, and really overgrown most of the year. The snowshoes get me around the seeps and over the prickly black locust. 
Well, most of it.

Yes, there is a creek there. Well, a flowage.
Is it a 'navigable waterway?
Depends upon the size of your boat, I guess. The beaver consider
it enough to try and dam up, so that to me, makes it official.

If you follow the creek far enough to get behind the neighboring apartment complexes, you come upon the scrubby willows full of "Witches Brooms."
These are weird growths that  make the twiggy branches look like, well, old besom brooms. 
A bit Harry Potterish. 
We also see them fairly frequently in evergreens when inspecting Christmas tree farms.
There are numerous things that can cause these strange growths. Often they are thought of as being "galls", but don't always fit that definition in the strictest sense of the term.

According to Paula Flynn from the Iowa Department of Plant Pathology, "In medieval times, mysterious and unexplainable occurrences were often blamed on witchcraft. Brooms during this time were made of bundles of twigs. 
The term witches' broom comes from the German word Hexenbesen, which means "to bewitch (hex) a bundle of twigs" (besom).
Witches' brooms occur on many different woody plant species, including deciduous trees such as hackberry, maple, and willow, and conifers such as pine and spruce. 

Here's a double.

There may be only one broom per tree, or they may be many scattered throughout the tree. In some cases, the brooms are quite large in size and are easily spotted. In others, they are small and well-hidden.
A number of stresses, both biological and environmental, can lead to the formation of brooms. Organisms such as fungi, phytoplasmas (bacterial-like organisms), mites, aphids, and mistletoe plants can cause abnormal growth when they attack a host tree. 
Environmental stresses that injure the growing points of branches can also trigger the formation of brooms. 
Some brooms appear to be caused by genetic mutations in the buds of the branches. Unlike brooms caused by living organisms, there is usually just one broom per tree when the cause is a genetic mutation. Pinpointing the cause of a witches' broom can be difficult, especially if the formation is related to an (abiotic) environmental factor."
Cool stuff. Mutant plants. And there is so much of this when you really start looking closely at growing things.
Cultural history, natural history, genetics, physics, botany, ecology, environmental science, and aesthetics all twisted up in some scrubby little branches. And these are the things that we can actually see. 
Imagine what is there that we cannot see...