Combining Eucalyptus wood production with the recovery of native tree diversity in mixed plantings: Implications for water use and availability

Author(s)

Amazonas, Nino Tavares ^[1] ; Forrester, David I. ^[2] ; Oliveira, Rafael Silva ^[3] ; Brancalion, Pedro H. S. ^[1]

Affiliation

^[1] Univ Sao Paulo, Escola Super Agr Luiz de Queiroz, Dept Ciencias Florestais, Lab Silvicultura Trop, Ave Padua Dias 11, BR-13418900 Piracicaba, SP - Brazil

^[2] Swiss Fed Inst Forest Snow & Landscape Res WSL, Birmensdorf - Switzerland

^[3] Univ Estadual Campinas, Inst Biol, Dept Plant Biol, Caixa Postal 6109, BR-13083970 Campinas, SP - Brazil

• Document type: Journal article
• Source: FOREST ECOLOGY AND MANAGEMENT; v. 418, n. SI, p. 34-40, JUN 1 2018.
• Web of Science Citations: 4

Abstract

Mixed forest plantations now emerge as an alternative to traditional plantations in the tropics and represent ecological gains associated with production, wood quality and nutrient cycling. Mixed plantations with higher diversity may also be advantageous concerning their use of soil water. To shed light onto water-related issues of mixing Eucalyptus and a high diversity of tropical native trees, we explored the following questions: What is the impact of high diversity mixed plantations of Eucalyptus intercropped with native trees on soil water? How does the mixture affect the physiology of water use in native trees? Firstly, we tested the hypothesis that stands of Eucalyptus mixed with a high diversity of native trees consume less water compared to Eucalyptus monocultures, by measuring the temporal dynamics of soil water. Secondly, we tested how mixing with Eucalyptus affects the hydraulic performance of fast- and slow-growing native species in these forestry systems. This is the first time a large experiment has been implemented to compare the effects of monospecific Eucalyptus plantations, native species mixtures and mixed plantations of Eucalyptus and native species on soil water dynamics under controlled conditions in terms of site, age, soil type, topography and climate. We found that high diversity mixed plantations of Eucalyptus and native trees use less soil water, than Eucalyptus monocultures. However, the soil under the mixtures was drier than in native species stands. The mixing with Eucalyptus affected the hydraulic performance of native species by decreasing the leaf water potential and stomata] conductance of the fast-growing species, suggesting that fast-growing species performance may be especially constrained by competition for water from Eucalyptus. These findings have important implications for forest management and ecological restoration in the tropics. They will help to further develop silvicultural options to adapt to climate change and improve plantation forestry by using mixed plantations for production purposes or rehabilitation of degraded lands. (AU)

• FAPESP's process: 14/02070-9 - Challenges and opportunities of the use of eucalyptus as a commercial pioneer species in forest restoration
• Grantee: Nino Tavares Amazonas
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/50718-5 - Ecological restoration of riparian forests, native forest of economic production and of degraded forest fragments (in APP and RL) based on restoration ecology of reference ecosystems in order to scientifically test the precepts of the New Brazilian Forest Code
• Grantee: Ricardo Ribeiro Rodrigues
• Support type: BIOTA-FAPESP Program - Thematic Grants