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

Author(s)

Ferraz, Silvio F. B. ^[1] ; Rodrigues, Carolina B. ^[2] ; Garcia, Lara G. ^[3] ; Pena-Sierra, Diana ^[4] ; Fransozi, Aline ^[4] ; Ogasawara, Matheus E. K. ^[4] ; Vasquez, Katherine ^[4] ; Moreira, Rildo M. ^[1] ; Cassiano, Carla C. ^[5]

Affiliation

^[1] Univ Sao Paulo, Dept Forest Sci, Luiz de Queiroz Coll Agr, Padua Dias Av 11, BR-13400970 Piracicaba, SP - Brazil

^[2] Prat Socioambiental, Guararema - Brazil

^[3] Forest Sci & Res Inst, Piracicaba - Brazil

^[4] Univ Sao Paulo, Luiz de Queiroz Coll Agr, Forest Resources Grad Program, Piracicaba - Brazil

^[5] Univ Fed Mato Grosso, Fac Forestry Engn, Cuiaba - Brazil

• Document type: Journal article
• Source: Hydrological Processes; v. 35, n. 9 SEP 2021.
• Web of Science Citations: 0

Abstract

Fast-growing forest plantations have been expanding in Brazil in the last 50 years, which reach productivities by over 40 m(3) ha(-1) year(-1) in reduced rotation between 5 and 15 years. In the 1990s, environmental warnings about these plantations guided research projects seeking to understand their effects on water and propose forest management actions to minimize them. The assessment of forest management effects on water resources is conducted by long-term experiments in paired catchments. In this paper we present results of some studies conducted at the hydrological monitoring centre of Itatinga Experimental Forest Station, of the University of Sao Paulo, where hydrological monitoring began in 1987, and currently include three catchments (83-98 ha) under different forest management regimes: short-rotation Eucalyptus plantation, long-term forest plantation mosaic and native forest restoration. Results show that at similar conditions observed at study area including deep soils and good natural water regulation, hydrological effects vary according to the forest management regime adopted, increasing water consumption and making the flow regime vulnerable to intra- and inter-annual seasonality. Regarding water quality, weekly sampling results showed suspended sediments and nitrate concentrations below water quality thresholds criteria by silvicultural operations, and the effects were transient but higher concentrations of nutrients were observed in intensive management regime. In the study area, reducing the management intensity of forest plantation by increasing the rotation time, adopting forest age mosaic and avoiding the coppice technique are alternative choices that reduced water use and increased flow regulation. Different adopted forest management schemes directly affected water use, showing that in water-deficit tropical regions, management regime of fast-growing forest plantations controls water availability. (AU)

• FAPESP's process: 16/02877-5 - Impact of climate change on the hydrologic regime of streams in Southeastern Brazil
• Grantee: Silvio Frosini de Barros Ferraz
• Support Opportunities: Research Program on Global Climate Change - Regular Grants
• FAPESP's process: 13/22679-5 - Eco-hidrological functions of riparian forests in intensity gradients of agricultural landscape management
• Grantee: Silvio Frosini de Barros Ferraz
• Support Opportunities: Regular Research Grants
• FAPESP's process: 15/23719-6 - The role of native vegetation on offering water regulation services in agricultural catchments
• Grantee: Aline Aparecida Fransozi
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)