When a tree is surrounded by many similar individuals, its mortality increases, which is probably caused by specialized pathogens or herbivores. This effect occurs in forests all over the world, but is more pronounced in rare tropical tree species, which could contribute to the astonishing tree species diversity of tropical forests.
This is important and good research, but I can’t help but laugh desperately at how this is yet another piece of research that can be summarised as “biodiversity good”.