Seed coating experiment
We observed an increase of 9.33% in seed germination rate when seeds were treated with the biochar-dominant seed coat in comparison with the control at all three sites (SE=0.04, p< 0.05; Figure. 3). The clay-dominant seed coat did not significantly improve germination rate (p=0.38; Figure 3), and there was no significant difference in seed germination rates between the seed coat treatments (p=0.15; Figure 3). Exploring the seed germination and seed treatment relationships further, we found that different species had different effect sizes for the different seed treatments. 14.35% of Celtis sinensis seeds (SE=0.07, p< 0.05) and 10.65% of Sterculia lanceolataseeds (SE= 0.05, p< 0.05) germinated more when treated with a biochar-dominant seed coat than the control seeds (Figure 4). However,Reevesia thyrsoidea and Ormosia semicastrata did not have significantly different germination rates between the three treatments. We noted that heavy rain washed away a substantial amount of seeds, leading to a small remaining sample size of these two species.