odd aerial root mass on trunk of Washingtonia robusta

[Eric in Orlando]

I saw this Washingtonia robusta near the Ft. Lauderdale Convention Center last week. It has an odd aerial root mass on the trunk about 5ft up the trunk. What causes this? Injury ?

[redant]

I have seen this on coconuts as well, no idea what causes it.

[Eric in Orlando]

"Its not a tumor!!!"

[Palms1984]

These adventitious roots are pretty common on Washingtonia robusta in California. Though, I'm not sure what causes them.

Edited January 26, 2011 by Palms1984

[Jerry@TreeZoo]

It's a pretty common thing on a lot of palms. I don't know the exact mechanism that triggers it but it looks obvious to me that trees in habitats with shifting sands like deserts (Wasingtonia) and beaches (Coconuts) use this adaptation to root out into a higher soil grade. Even Royals do this occasionally, to deal with either swampy conditions or heavy leaf litter.

[DavidLee]

My thoery is that it was cause by some kind of injury. Like a trunk bumping into it or lightining. I have a 35 foot Washingtonian robustas at my mom's place in Florida. One of them has a large mass of aerial roots from the ground to about a 2 foot up. My theory is it caused by to much water intake during the summer rain season. One time when it rained day after day I notice some splitting to the trunk. Few weeks later more aerial roots coming out. I guess the aerial roots is away it repairs itself since palms are monocots and dont have the ability to heal an injuried trunk.

[Enzo]

Usually this behavior is caused by the tearing premature of the old leaves(is surely due to trauma), creating fissures on the trunk, after exits the roots.