The Dangers of Root Disturbance
One of the biggest causes of tree death or felling is root disturbance. Construction for example almost always includes some type of damage to a tree’s roots. You have to understand that 90% of a tree’s roots are located in the first 12 to 18 inches of soil.
Root disturbance can screw up the entire structural integrity of a tree putting it at risk to fall. Remember that roots are the main source of nutrients for a tree, it’s how they eat and drink. If there is damage, they won’t be able to absorb nutrients to survive and grow.
You should pay attention to city ordinances regarding landscaping guidelines and trees as to avoid issues.