Abstract:[Objective]The effects of soil physical properties on preferential flow vary significantly across regions. This study aimed to clarify the mechanisms to provide practical implications for assessing forest hydrological effects and guiding sustainable forest resource management.[Methods]Three forest stands(oak forest,pine forest,and bamboo forest)in Kongqingshan,Jiangsu Province,were selected. Dye-tracing experiments under simulated rainfall(50 mm/h)were conducted,and soil preferential flow patterns were analyzed using soil physical property measurements and image processing techniques.[Results]1)Significant preferential flow phenomena were observed in the soils of all forest stands(p<0.05). The dyeing area ratios in different soil layers were 41.54%-90.00%,9.27%-90.11% and 18.19%-93.93% for oak forest,pine forest,and bamboo forest, respectively. The fractal dimensions of dye-stained patches were 1.23-1.59,1.62-1.96 and 1.68-1.97, respectively. The number of dye-stained patches were 2-12,13-160 and 22-360,respectively,with significant differences (p<0.05). The widths of dye-stained patches were 2.50-3.27, 0.47-3.24 and 0.37-2.59 cm, respectively,with significant differences(p<0.05). The preferential flow ratios were 91%±3%,27%±7% and 51%±7%,respectively,with significant differences(p<0.05). The matrix flow depths were(14.5±7.3), (17.9±3.9)and(16.8±3.8)cm,respectively. 2)In all three forest stands,the dyeing area ratio was negatively correlated with soil bulk density(p<0.001)and positively correlated with total porosity(p<0.05). The fractal dimension of dye-stained patches was positively correlated with soil moisture content(p<0.001). The number of dye-stained patches was positively correlated with clay content(p<0.05),while the width of dye-stained patches was negatively correlated with soil moisture content. 3)The dyeing area ratio and the fractal dimension of dyestained patches,as key parameters of preferential flow,showed high goodness-of-fit when modeled with soil physical properties using multiple linear regression equations. These two parameters were relatively more important in their correlations with soil bulk density and porosity.[Conclusion]The soil infiltration properties at different depths of oak forest,pine forest,and bamboo forest exhibited significant differences. Soil bulk density and total porosity are key drivers of preferential flow development.