We generally place tubes like these next to trees when planting as they allow you to water deep down into the plant's root ball. They prevent excess evaporation of surface water and make sure all of it is directed to where it's needed. Simply place your hose in the tube for 10mins for deep watering of the plant. You'll often find councils use this agricultural pipe method on trees they plant on the nature strip. Whilst establishing the plant, a council water truck with a boom arm will come along and water them through the pipe.