3 Results
3.1 Rooting depthwith different RFC treatments
The fine root depth of the three woody species increased with the increase in RFC gradient, and these species exhibited the deepest distribution at 75% RFC over the 3 years (Fig. 1 and 2). However, the rooting pattern of fine roots in A. vestita was contrary to that of the other woody species along the RFC gradient (P < 0.01, Table S1). The fine root depth coefficient (β ) ofA. vestita decreased with increasing RFC and was the largest in rock-free soil over the 3 years (Fig. 1 and 2 a). With the increase in age, the variation range of fine root depth along the RFC gradient showed an increasing trend in A. vestita (Fig. 2 a–d), but showed a decreasing pattern for the three woody species (Fig. 2)