What do the markings on the tree stumps mean?

Perhaps there is one or two foresters, forest workers or head foresters around here who can answer my curious question: Trees were cut down in our favorite wooded area for walking the dog. And of course, the stumps are still in the ground with their roots. Now I've noticed that a "pattern" has been sawn…

Is it not a problem in terms of noise to cut down a tree with an electric saw in a city on a Sunday?

In my area, trees have to be felled that do not require a permit in our city. It is not currently the bird protection period either. The person who would carry out the felling in exchange for the wood can currently only do so on Sundays. He wants to do this with an electric chainsaw,…