The ice storm picture paints a real snapshot of the devastation of nature and lets us know who is really in control.
Part of this is due to the dreary sky, the pale palette and the lack of contrast even between the snowy background and the dark bark of the trees.
I agree Cathy this is a real challenge.
I will not say it cant be done, but I wonder, like you, how usable a pattern will be.
We have to define the trees, some are erect and some have fallen.
One defining feature is the placement of the ice on the limbs. A problem with that is the ice is the same colour and texture of the background
The ground is smooth and white so it shows no detail, the sky is virtually the same. This part is easy we don't have to do anything here.
There are 4 distinct layers in the photo, foreground, middle, middle back and distance.
We could cut 4 layers and build the pattern up from that. Each one would be a physical layer depicting a different depth in the image. Something like paper tole.
This would have to be done manually.
We could scan the photo based on tonal value, each tone being a different layer to the puzzle. There is an example of a three tonal scan image done with inkscape.
We could adjust the overall tonal value and reduce this to 2 colours and we get the start of a fretwork stencil. This was done with Serif PhotoPlus.
Personally I would use a layered method, I think it would be extremely difficult to cut an effective fretwork pattern, given the subject matter is all tones in a monochrome palette and increasing contrast only leads to decreasing the ability to recognize the image.
Someone else jump in and rescue me and prove me wrong now

Thats whay this thread is about