Having just seen the footage again on the news I am wondering if it was birds. Possibly debris from a blade strike with the tree?
The eye witness report reports loud noises which could have been a blade strike.
The natural reaction would have been a rapid move away from the strike which would have taken it directly into the other aircraft.
A tragic accident no doubt partially attributed to the pressure of the TV role and wanting it to "Look Good"!
Having just watched DR link I now don't think it was a blade strike.
The far a/c seems to be turning right as the near one veers left.
Let's hope more information will be forthcoming so that a similar incident can be avoided!