Fertilizer will benefit such soils and improve the growth of trees planted on these areas. Trees growing on good soils will also benefit from fertilization. This is especially true if the soil is compacted or if normal root growth is restricted by sidewalks, driveways or building foundations. Fertilizer also helps develop good leaf color, recovery from insect, disease or other injury, and stimulates general tree vigor. There is no single indicator that trees need fertilization.
Some nutrient deficiencies cause specific discoloration in the foliage.
Chlorosis is the most common condition of this type. It results in the development of a light, yellow-green color, especially in the areas between the veins. It is most often associated with a lack of available iron. Many kinds of materials can be added to the soil to improve fertility, however, some are more effective than others. Organic residues such as peat moss, manure, wood chips, etc. are beneficial in improving the physical properties of the soil, but they will not greatly increase the nutrient content of the soil unless added in large amounts over a number of years.