Corrective Pruning Corrective pruning can be done to improve the overall health and of a tree. Chlorosis Chlorosis is a micro-nutrient deficiency where the tree lacks iron or manganese. Compacted Soil When soil becomes too tightly compacted, plants and trees are not able to properly grow their roots. Girdling Roots Girdling roots occur when the roots of a tree wrap around the base of the tree. This causes the flow of water and nutrients to be choked off from the rest of the tree. Plant Growth Regulator Plant growth regulators are substances that profoundly influence the growth and development of plant cells.