@HDMI1 thats common knowledge... but those are WorldTrees and on top of that, two spirits inside..... thats little different situation
you can see how big was the fully grow one... and what about two ... wouldnt they suck too much energy?, could survive when so close?.....
Trees usualy not grow so close, because they killin each other, coexistence is very rare, it need lot of natural resources to mantain life.
So when you consider their sizes, and reguired energy to mantain... its too close