Maintain and promote the health and vigor of your trees and shrubs by providing them with the necessary nutrients for growth. In a forest environment, trees benefit from the recycling of organic matter, but urban sites are often lacking nutrients. Sites containing back-fill soil and sites with limited rooting area may also lead to nutrient problems. Additionally, high pH levels can cause some nutrients to be unavailable for uptake. Although some situations do not warrant fertilization, most trees in the urban setting will benefit greatly from this service.