Runoff and sediment yield from forested catchments under varying management intensities: Insights from a subtropical region of Brazil

Abstract

Streams have tolerance limits to certain environmental conditions, high levels of sediment can influence water quality and, consequently, aquatic life and human health. Considerable research in temperate forest ecosystems has elucidated the dynamics of suspended sediment export and the role of forest management on changing sediment yields, but fewer studies for subtropical regions exist. The objective of this study was to evaluate the effects of forest management on suspended sediment export under varying forest cover and management conditions in subtropical Brazil. Three catchments, with different management systems, were evaluated: eucalyptus forest plantation with even‐age stands management (EUC), native forest (NAT), and mosaic of forests plantation with different species and ages (MOS), located in southeastern Brazil. Streamflow, precipitation and turbidity data were collected by pressure transducers, automatic rain gauge and YSI 6136 turbidity sensors, respectively, during the period from November 2016 to October 2017. The suspended sediment yield was estimated through a relationship between turbidity and suspended sediment concentration. The results showed that sediment export ranged from 0.032 Mg ha−1 yr−1 to 0.411 Mg ha−1 yr−1. The catchments studied presented a low sediment export rate, compared to other studies conducted in forested settings worldwide. Our results provide insights into the high‐frequency sediment production dynamics of Brazilian forested catchments and demonstrate that, regardless of the forest management system applied in the area, native or exotic planted forests are capable of protecting the soil and minimizing the effects of sediments export.

The medium‐term effects of forest operations on a mixed broadleaf forest: Changes in soil properties and loss of nutrients

“…Comparing the results with the current literature it can be stated that the obtained findings are in agreement with previous studies on the topic carried out in similar stands but with a shorter time‐span focus (Abari et al, 2017), confirming the direct relationship between management intensity (Ogasawara et al, 2021) and erosion, as well as between machinery‐induced soil compaction and erosion (Nazari et al, 2021).…”

“…The notable amount of literature on the topic of the influence of forest operations on runoff shows that this has been studied extensively. The reason for this is easily understood considering the importance of this topic (Ogasawara et al, 2021).…”

How do management alternatives of fast‐growing forests affect water quantity and quality in southeastern Brazil? Insights from a paired catchment experiment

“…The slight variations observed in the annual mean values demonstrate the natural dynamics that occur in aquatic ecosystems (Vannote et al, 1980). It was possible to note a trend of reduction in the concentrations of suspended sediments and nitrate, which is expected due to the absence of clearcutting in total area and forest management carried out in small portions of the catchment, a result similar to that observed in other studies (Cassiano et al, 2020; Ogasawara et al, 2020; Riekerk, 1983; Tremblay et al, 2009). Thus, despite the maintenance of water use compared to commercial plantations, the results indicate that the benefits of less intensive forest mosaic may be related to the maintenance of the hydrological processes of infiltration and percolation, which are essential for soil and water table recharge and for the control of surface runoff and erosion.…”

Efeito de florestas plantadas de eucalipto sobre os aspectos qualitativos e quantitativos dos corpos hídricos e os nutrientes no solo

“…O artigo mais recente a respeito da exportação de sedimentos por corpos hídricos em bacias com cultivo de eucalipto é o de Ogasawara et al (2020), que estudaram a fase pós corte raso de eucalipto com sete anos no Brasil -São Paulo. Os autores reportaram a maior exportação de sedimentos pelo corpo hídrico que drenava área sem cobertura vegetal pós corte do eucalipto (411 kg ha -1 ano -1 ) quando comparada a outro corpo hídrico que drenava área que também passou por corte raso, mas na qual foi implementado um processo de restauração com plantio de espécies de vegetação nativa (214 kg ha -1 ano -1 ).…”