Treated With Perimeter Solutions LC95 Fire Retardant
The lower Portion that you see actively burning has not been treated.
The upper portion not burning has been treated with Perimeter-Solutions LC95 Fire Retardant
To give you an idea of how much embers can be given off by palm trees. This is one palm tree that is putting off a significant amount of embers on a non-windy day.
How do embers spread? Watch this animated video.
This video explains how ember cast can explode and start additional fires.