Watering trees after planting would help in their survival and growth, as compared to not watering at all. Trees with a lack of watering would lead to higher mortality rate, and are more susceptible to pests and diseases. As roots spread out and make contact with more soil volume, the frequency of watering could be reduced. Establishment of trees could be assessed visually by observing twig elongation.
The volume of water required is minimally 1.5 to 3 liters per cm of tree diameter, though irrigation frequency is important, and ultimately determines whether the tree is being maintained for survival or vigour (Table 1). Please note that this guideline does not apply to trees in a tropical climate, as it is warmer and that promotes transpiration in plants.
Reference
1. Boldly Planting for the Next Generation, Oct 2021, Arborist News
