Human activities and natural disasters are the major contributors to the decline of M. sieversii natural population. Fungal pathogens, such as Phytophthora plurivora and Alternaria alternata, also play a major role in the decline of M. sieversii populations, by degrading vegetative parts such as the fine root systems. This immune vulnerability makes M. sieversii become susceptible to more parasites, such as pathogenic insects Agrilus mali, to further destroy the population.
