Thanks for all the positive feedback.
You probably need to select “use with instances” in material details. Just open your material and in details panel type “instance” in the search box, and the option should be right there.
All trees i used for testing were, if I remember correctly, from vehicle game desert map. The material of palm tree is quite heavy, so if i got tree in my spawn pool I try not to go over 5k objects. If I only spawn cactuses I can easily spawn over 10k+. I did some testing with 40k+ objects on the map but the performance hit was too big.