2025-07-02

Recovery of tree species functional composition in eucalypt plantations with natural regeneration differs among canopy strata

Laura H.P. Simões^{a, b, 1}, Marielos Peña-Claros^b, Joannès Guillemot^{a, c, d}, Rens Brouwer^{b, e}, Frans Bongers^b, Lourens Poorter^b, Catherine T. de Almeida^f, Danilo R.A. Almeida^{a, g, h}, Miguel Cooperⁱ, Mathieu Decuyper^b, José G. Fernandes Neto^j, Matheus S. Fuza^a, Renato A.F. Lima^k, Juliano van Melis^a, Paulo G. Molin^l, Angélica F. Resende^a, Ricardo R. Rodrigues^{k, m}, Vinicius C. Souza^k, Ari F. de Toledo Jr^a, Cássio A.P. Toledo^k, Pedro H.S. Brancalion^{a, m, n}

^a Department of Forest Sciences, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Brazil
^b Forest Ecology and Forest Management Group, Wageningen University & Research, Wageningen, the Netherlands
^c CIRAD, UMR Eco&Sols, Montpellier, France
^d Eco&Sols, University of Montpellier, CIRAD, INRAe, Institut Agro, IRD, Montpellier, France
^e Forest and Nature Management, Van Hall Larenstein University of Applied Sciences, the Netherlands
^f Department of Geography, Federal University of Paraná, Brazil
^g Bioflore, Brazil
^h brCarbon, Piracicaba, Brazil
ⁱ Department of Soil Science, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Brazil
^j Applied Ecology Graduate Program, University of São Paulo, São Paulo, Brazil
^k Department of Biological Sciences, “Luiz de Queiroz” College of Agriculture, University of São Paulo, Brazil
^l Center for Natural Sciences, Federal University of São Carlos, Buri, SP, Brazil
^m Re.green, Rio de Janeiro, Brazil
ⁿ Center for Carbon Research in Tropical Agriculture, University of São Paulo, Piracicaba, Brazil

Highlights

Traits were assessed in eucalypt stands with native understory and regrowing forests.
Community traits are affected by canopy strata interacting with restoration method.
Eucalypt trees dominate top stratum of plantations, shaping community trait values.
Lower strata in eucalypt stands and regenerating forests show similar trait values.

Abstract

Tree monocultures have been promoted globally to supply timber; yet, a high diversity of native trees can establish in less intensively managed plantations, allowing to both harvest timber and transition towards a more natural forest. However, little is known about the functional recovery of native trees under plantations, which is critical for biodiversity conservation and ecosystem services. Here, we evaluate how functional composition of tree strata differs between two restoration methods (eucalypt plantations with natural regeneration and naturally regenerating forests) and how this is affected by stand age, climatic water deficit, and soil characteristics. We established 129 plots in two restoration methods and mature forest as reference, in São Paulo state, Brazil. We divided tree stratum in each plot into different canopy strata using perfect plasticity approximation. We measured five key traits that are important for fire resistance (bark thickness), drought tolerance (wood density), productivity (specific leaf area and leaf thickness), and nutrient cycling (nitrogen-fixing ability) for 393 species and calculated for each stratum community-weighted mean trait values. Community traits were mostly affected by canopy strata, the interaction between canopy strata and restoration method, and water availability. Eucalypt trees dominated the upper strata of plantations, presenting higher wood density, tougher leaves, and thicker bark, reflecting the drought and fire adaptation of eucalypts. The lower strata of eucalypt plantations and naturally regenerating forests had similar functional composition. Our results suggest that eucalypt plantations can be used as a tool to facilitate natural regeneration and restore ecosystem functioning in degraded areas.