The study looked at litter production and nutrient return in three types of plantations in Guangyuan City. They found that the amount of litter produced varied between the plantations, with Robinia pseudoacacia having the highest leaf litter production. Nutrient return was highest in the Robinia pseudoacacia stand and lowest in the Pinus eliottii stand. Overall, broad-leaved forests like Robinia pseudoacacia are better at maintaining soil fertility compared to needle-leaved forests like Pinus eliottii.