Paired catchments
The four catchments are on the same geological formation, sandstone from sedimentary rocks. The C1 catchment has 57.5% of its area under Rhodic Hapludox and 42.5% under Typic Hapludox, the same soil found in more than 95% of the area of the C2, C3 and C4 catchments. The catchments have similar physiographic characteristics (Table 1).
The catchments have riparian vegetation [native vegetation] preserved along the watercourses, with canopy of Eucalyptus saligna and understory with native species characteristic of semi-decidual seasonal forest in regeneration (Santos et al., 2019). The area with native vegetation represents 8%, 48%, 13% and 44% of the areas of the C1, C2, C3 and C4 catchments, respectively. The C1 catchment has a mosaic of forest plantations [forest mosaic] in 87% of its area, C2 has 52% of its area in the process of native forest restoration, and C3 and C4 have 80% and 50%, respectively, of their areas with commercial eucalyptus forests [Eucalyptus plantation].
The C1 catchment is under a regrowth cycle that underwent clearcutting in 1997 (Câmara & Lima, 1999). From harvest in 1997, the occupation of the catchment has been diversified with different species ofEucalyptus spp. , at different ages, in addition to planted forests of Pinus spp. , Araucaria angustifolia andAcacia mangium , in a smaller proportion, forming a forest mosaic of species and ages [forest mosaic].
The C2, C3 and C4 catchments were covered by clonal Eucalyptus plantations, under forest management in a short cycle (< 7 years) with conduction of regrowth. This management system was implemented more than 30 years ago in the area, with replanting of the plantations, on average, every 14 years. After the harvest in 2014, there was regrowth of the plantation without conduction, leading to a new clearcut in 2016 in the C2 and C3 catchments. In C2, after the clearcut of 2016, a native forest restoration process began in the area initially occupied by planted forests [eucalyptus plantation]; while in the C3 catchment there was the replanting of eucalyptus plantations. In the C4 catchment there was the conduction of the regrowth [eucalyptus coppice], initiated after the 2014 harvest.
C2 and C3 had their areas replanted in 2016. The forestry practices adopted in the implementation included the monitoring and control of leaf-cutting ants using granulated bait; control of invasive plants with chemical and manual weeding; application of dolomitic limestone in total area; subsoiling with agricultural tractor; manual planting of seedlings; basal and top-dressing fertilization with NPK; manual application of pre-emergent herbicide in the planting row and replanting of gaps.