*4.2. E*ff*ects of Natural Environment on S.* × *hainanensis Seed Germination*

In the wild environment, in addition to abiotic factors (light, temperature, salinity), seed germination was also affected by biological factors (animals, diseases) [36]. The study of *Taxus chinensis var. mairi* has showed that only very small portions of the seed rain supplied the seed bank, and most of the falling seed did not replenish the soil seed bank due to predation, human disturbance, and environmental factors [37]. Seeds of *Phoebe bournei* were not only susceptible to soil pathogens, but to high predation beneath parent trees' canopy as well, which resulted in poor field seed germination [38].

In this experiment, the fruit drop of *S.* × *hainanensis* was serious during fruiting stages, and only the seeds of mature stage had higher germination rate (about 40%), and the seed germination rate in other periods was very low (less than 10%), so most of the fruits were wasted. Because the fruit of *S.* × *hainanensis* was sweet, it was welcomed by animals such as squirrels and Fiddler crabs. Most of the seeds were destroyed and could not be germinated. Therefore, seed predation by animals was also one of the reasons that the seed germination of *S.* × *hainanensis* was limited.
