Citrus tree growth is upright in most varieties. During the first years, there is no need to prune, since research has shown that any cut to a young tree reduces root growth. This is due to the equilibrium between foliage and root system. A citrus tree is a biological unit. Heavy cuts on a young tree discourages canopy growth and delays the tree to come into bearing. After a few years, depending on the speed of the growth a selective canopy THINNING may be carried out. The choice of branches to eliminate is based on the concept that any space within the canopy must be covered by only ONE branch. It is not wise to let surplus branches occupy the same aerial space. It is important that thinning does not deplete any canopy sector. A harmonious citrus tree grows to an almost round shape. Vegetation free canopy spaces must be avoided since they reduce yield. In citrus areas such as the United States, Brazil, etc. pruning is either practiced rarely or not at all. Unpruned trees come into bearing quickly and yield crops for many years. After many years of growth crops are reduced and fruits become smaller. This is the time to make heavy cuts and renew growth.