Arborists specialize in tree care, they are trained and equipped to provide proper tree care. Your urban ecosystem is as complex as any forest or wooded area, although they are not natural. Urban ecosystem's generally have low species diversity, isolated trees, poor rooting space, poor nutrient cycling, compacted soils, de-icing salts, pesticides and a lack of water. Our trees and plants need help to survive and flourish naturally.
If you cannot recognize and prescribe a course of action for the following, you should hire an Arborist.