Abstract

Infiltration is one of the most important hydrological processes in ecosystems, having important influence on soil erosion control and runoff, soil moisture content and groundwater recharge. This is particularly important considering the recent growing number of restoration initiatives worldwide encouraging forest cover expansion, mainly by tree planting. Here, we conducted a systematic review of scientific literature reporting infiltration measurements in forests restored by tree planting in the tropics and subtropics. We found 11 studies representing 67 data comparisons in eight countries. Overall results indicate that infiltration increases but is not fully recovered to reference conditions in forests restored by tree planting. Recovery of infiltration varied depending on land-use, soil texture and restoration age. Recovery of infiltration was higher for cultivated than for pastures and bare soils. Clayey soils had higher infiltration recovery than sandy soils. Our findings identified some knowledge gaps that should be addressed to improve our understanding of when and why tree planting to restore forests may promote the recovery of infiltration in tropical and subtropical soils. First, information about recovery of infiltration capacities when using tree planting for forest restoration results are scarce. Second, infiltration in restored forests should be monitored over time, including long-term studies and measurements on water movement through the soil profile and evaluating potential interactions between infiltration and soil attributes. Details on the effects that different forest restoration techniques (e.g., soil preparation, tree species diversity and densities) could have on infiltration is virtually unknown. Information on the influence of disturbance level on infiltration prior to tree planting is also severely lacking.