Mixing Eucalyptus and Acacia trees leads to fine root over-yielding and vertical segregation between species

Author(s)

Laclau, Jean-Paul ^{[1, 2]} ; Nouvellon, Yann ^{[3, 1]} ; Reine, Caroline ^[4] ; de Moraes Goncalves, Jose Leonardo ^[5] ; Krushe, Alex Vladimir ^[6] ; Jourdan, Christophe ^[1] ; le Maire, Guerric ^[1] ; Bouillet, Jean-Pierre ^{[5, 1]}

Affiliation

^[1] CIRAD, UMR Eco & Sols, F-34060 Montpellier - France

^[2] Univ Estadual Sao Paulo, UNESP, Dept Recursos Nat, BR-18610307 Botucatu, SP - Brazil

^[3] Univ Sao Paulo, IAG, Dept Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil

^[4] Univ Lorraine, INRA, Lab Sols & Environm, F-54505 Vandoeuvre Les Nancy - France

^[5] Univ Sao Paulo, ESALQ, Dept Ciencias Florestais, BR-13418900 Piracicaba, SP - Brazil

^[6] Univ Sao Paulo, CENA, BR-13416000 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: Oecologia; v. 172, n. 3, p. 903-913, JUL 2013.
• Web of Science Citations: 29

Abstract

The consequences of diversity on belowground processes are still poorly known in tropical forests. The distributions of very fine roots (diameter < 1 mm) and fine roots (diameter < 3 mm) were studied in a randomized block design close to the harvest age of fast-growing plantations. A replacement series was set up in Brazil with mono-specific Eucalyptus grandis (100E) and Acacia mangium (100A) stands and a mixture with the same stocking density and 50 % of each species (50A:50E). The total fine root (FR) biomass down to a depth of 2 m was about 27 % higher in 50A:50E than in 100A and 100E. Fine root over-yielding in 50A:50E resulted from a 72 % rise in E. grandis fine root biomass per tree relative to 100E, whereas A. mangium FR biomass per tree was 17 % lower than in 100A. Mixing A. mangium with E. grandis trees led to a drop in A. mangium FR biomass in the upper 50 cm of soil relative to 100A, partially balanced by a rise in deep soil layers. Our results highlight similarities in the effects of directional resources on leaf and FR distributions in the mixture, with A. mangium leaves below the E. grandis canopy and a low density of A. mangium fine roots in the resource-rich soil layers relative to monospecific stands. The vertical segregation of resource-absorbing organs did not lead to niche complementarity expected to increase the total biomass production. (AU)

• FAPESP's process: 10/16623-9 - Ecological intensification of eucalyptus plantations by association of nitrogen fixing leguminous tree species
• Grantee: José Leonardo de Moraes Gonçalves
• Support Opportunities: Research Projects - Thematic Grants