Trees Trimmed

I went home early yesterday and it was still bright when I walked by the park. There used to be a short trail from the bottom right corner to the left that I took every day as a shortcut. Now I just have to walk a bit longer (20 feet more at most, but far enough for me to complain) around the corner. And the trees had been trimmed! This is the second time I have seen such a thing in my neighborhood. I don't know how long it takes the trees to grow back, but are they not supposed to cover and give shade? Why did people not trim all the trees there, but just some instead? It looks so ugly now. It is like shaving few spots on the head, and leaving hair grow everywhere else on the head.