So common but why exactly?

Wrapping trees, especially evergreens, is an Ontario tradition. I did it one year, myself. I saw little benefit and haven't done it since.

So, why do so many folk wrapped their trees as winter approaches and do it without fail? First, this grouping of evergreens represents a fair investment. Each one of those wrapped trees would cost many hundreds of dollars to replace.

The trees are close to a busy road and therefore may suffer damage from salt spray drifting over from the road. Also, considering where these tree are located, near a large cemetery frequented by deer, the wrapping protects the trees from being nibbled by the neighbourhood pests. 

And evergreen trees are prone to suffering ice damage. A heavy build-up of ice can deform tree limbs or even break them. Many evergreens never fully recover from such damage. The burlap wrap prevents this.

Now, what is with the grey, squarish individual fence panels? I can offer no explanation.