Tree root systems are shallow and wide spreading. [Figure 1] Based on nursery standards, a field-grown, balled and burlapped (B&B) tree or container-grown tree has less than 5-20% of the fine absorbing roots of the same size tree in a landscape setting. This creates stress when the tree moves from the daily care in the nursery setting to the landscape. The Science of Planting Trees is promoting rapid root growth to reduce the water stress imposed by the limited root system. Postplanting stress (transplant shock) describes the stress factors induced by the limited root system.