Trees in the forest recycle their nutrients from the leaves, twigs and litter that fall to the forest floor. This is seldom the case in our urban landscapes, where our roots are often covered by lawns or pavement and all the natural nutrients may be cleaned up. Often the essential elements needed for our urban trees may be depleted or unavailable, especially in construction modified soils. Our prescription tree care method of meeting the plants needs are best determined by a soil and/or a leaf analysis. Importantly, elements and amendments needlessly or improperly applied may negatively impact the environment or have an adverse affect on your trees and shrubs.