Treat that tree like a... tree. Evenly distribute the water between the plant's trunk and the outer circumference of its canopy. You want to encourage root growth - not discourage it.
IMHO.
And be aware that plants use transpiration in order to self-cool, and that they'll use much more water on really hot days. You might type "how much water can a plant transpire?" (without the quotation marks) into your favorite web-search engine. I've had large - but certainly not as large as yours, lol - indoor plants go through seven, even 13 gallons of water each on really hot days when I had to boost the airflow and depend on the plants' transpiration abilities to keep them healthy. A large root system makes this more feasible, as the plant can draw moisture from a larger area. The only thing that constantly pouring water into a concentrated area right at the plant's trunk (again, "IMHO")... is rot.