Air pipes for newly planted trees?

Hi, I recently moved to LA from Chicago, and so I've encountered an incredible difference in planting trees. I don't know which forum handles this question...

One nursery we bought trees from suggested putting in AIR PIPES, 2-3, filled with gravel around tree ball. Yesterday, a transplanting company transferred a 20' Norfolk Island tree from daughter's house to ours (4 blocks). They installed a PCV, empty, except for gravel around pipe, going to the bottom just for checking to see if water is at bottom before adding more water.
I have tried to get info off Google regarding these AIR PIPES or PCV pipes. What really are they for? Since I've had trouble finding any further info on Internet, are they important to have?

Thank you
Vince

 

not sure but it sounds like a possible solution to very compacted soils for air/gas exchange?

 

Myth: Low-oxygen Root Zones Can Be Aerated by Installing Vertical Aeration Tubes (.pdf).

 

Are you sure they are not pipes for watering. This is done a lot here for street trees that are newly planted. A truck comes along about once a week and fills the 2 or 3 pipes to get the water right down under the mulch. Many people use a similar method with old inverted bottes during our water restricitions.

Liz

 

No, the one who planted the large Norfolk tree told me to check the water level by putting a stick into the PCV pipe to see if there's water. If there's a lot of water, to pump it out...probably bad drainage? Also, it was a way of knowing if the new tree needed slow trinkle.

 

thanks to Junglekeeper. That article seems definitive! I can see now why I have trouble finding this sort of procedure difficult while googling.
Thanks again
Vince