canopy management in fruit crops - Department of Agriculture & Co ...

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Canopy Management in Fruit Crops
Citrus
Citrus trees typically have 3-5 growth flushes a year depending on growing
conditions. Each new growth flush is added onto the previous growth flush,
resulting in a drift of young bearing wood to outsides of tree canopy. Over the time,
this results in larger trees with increased shading inside the canopy, developing
most of the fruits on the tops and outsides of trees.
Most of the fruits in Citrus are born on foliage about 90 cm along from centre
where light is adequate for fruit bud formation, while inside area is occupied mainly
by supporting structure without fruits.
Growth rates are highly variable depending on climate, cultural practices, tree
spacing, scion, and rootstock. Younger trees (approximately 5–10 years old) have
higher growth rate in relation to tree size. Once the tree reaches desired height,
annual pruning may be required to maintain the height, thin the growth, and
promote prolific fruiting. Maximum fruits are set on wood that is less than 2 years
old. Pruning is least damaging to tree yields when done on a regular basis to wood
on the outside of the canopy.
Pruning is done when trees are young to establish their basic shape and continues
as trees mature. In commercial orchards, pruning facilitates normal daily operations,
increasing the yield. Where trees have outgrown their allotted space, pruning can
increase the bearing surface. Trees that grow too close together shade out the lower
canopy portions and, in return, decrease fruit setting. If pruned to allow light to
reach the top and lower sides of tree, the increased bearing surface results in fruit
setting. Any sprouts arising from rootstock (i.e. from below the graft union) should
be removed.