Trees can be damaged or killed by a wide variety of construction activities.Some practices lead to obvious injuries such as broken branches or torn bark.Open wounds of this type deplete a plant's energy resources and provide entry points for insects,or for diseases such as oak wilt.The worst damage,however,often remains hidden underground.Roots are one of the most vital parts of a tree.They are responsible for nutrient and water uptake,store energy,and anchor the plant.Because they are so important,it is critical that you protect roots that lie in the path of construction.Trees are never the same shape below ground as they are above,so it is difficult to predict the length or location of their roots.Typically,however,approximately 90-95 percent of a tree's root system is in the top three feet of soil,and more than half is in the top one foot.The part of this root system in which construction damage should be avoided is called the Protected Root Zone