Oliver Tree's Girlfriend Breaks Silence After He Dies in Helicopter Crash

Oliver Tree's girlfriend is speaking out for the first time since he died in a helicopter crash in Brazil ... and she says folks need to shut up about "any other women that Oliver may have been seeing."

Fiona Chernavskaya hopped on social media Wednesday morning and set some boundaries, saying the last thing she needs right now is gossip about Oliver's love life ... claiming they were monogamous and kept their relationship "very intimate."

She thanked those who have been sending kind words and support ... and encouraged folks to show love to others affected by the tragedy as well.

Fiona added ... "right now im mourning my partner and best friend, anything else is unimportant. please have some respect."

She also posted an IG carousel and said of Oliver ... "You'd always tell me when we argued, if things don't work out in this lifetime, you will find me in the next.

One of the top comments is ... "God damn how many girlfriends did he have" ... and it seems that's what Fiona may be referencing here.

Oliver's ex, Melanie Martinez, had a quicker reaction the crash ... when reports first came out, she posted about being "an absolute wreck."

As you know, Oliver and 5 others were killed after two helicopters collided above an electric vehicle yard in Rio de Janeiro, Brazil ... with both choppers immediately bursting into flames and crashing to the ground.

In addition to Oliver, Argentine producer Lucas Vignale, YouTuber Gaspi, Lucas Brito Chaves, and the pilots of both crafts, Alexandre Souza and Charles Marsillac, died.