Interestingly, many forest stands are actually overpopulated with trees. Removal of organic matter helps the existing trees grow taller and more healthy, improves the habitat for other species and animals, and can result in a more biodiverse, healthier forest less vulnerable to parasites and invasives. It can also reduce the severity of forest fires.

Source: I manage forestland in the PNW for the purpose of habitat restoration, and was surprised to learn how removing tree mass from a system can actually improve the overall health and biomass of a system.

Nobody is suggesting doing this to every tree.