Mankind in control

TAs I walked through the forest, I saw all these lines on the trees. I thought it was a beautiful sight. The contrast between the bright color and the calm, natural colors of nature. But why are those stripes on the trees? The trees will have to be cut down. Does man think that the tree is sick and should go? Did they reject the tree? Do people think that it is better to use the tree for something else?
Why do they want to keep control like this? Let the tree die, let the tree bring new life to fungi and bugs. Let the tree become a new city.