If you don’t prune a tree, it can become overgrown and disfigured. Without proper pruning, the tree branches may grow in random directions, leading to an unbalanced growth pattern. This can cause them to become too heavy for the trunk, making them prone to breakage during storms or windy conditions. Additionally, branches that grow too close together can be more vulnerable to disease and pests. Overgrown trees also tend to become less attractive aesthetically and take up more space than necessary.

Without regular pruning, trees may not reach their full potential in terms of shape and size. The lack of regular maintenance will mean that it will be difficult to keep them looking neat and tidy as time goes on. 

This could lead to a reduction in their value aesthetically, as well as decreasing the amount of light they receive if they are too densely packed with foliage. Not only that, but unpruned trees are likely to require more maintenance later on if they do need intervention due to overgrowth – this means that this kind of work could be significantly more difficult and costly than necessary.

Overgrown trees can also cause damage to nearby buildings or vehicles by blocking out sunlight or by having their branches come into contact with such structures – often times the weight of these branches is enough for them to break through weak materials such as glass or thin metal sheets. 

Furthermore, large trees with numerous trunks growing together are much more unstable than a single central trunk – meaning that when storms strike, they pose a great danger due to the increased probability of collapse or severe swaying motions creating dangerous debris which can harm people nearby.