Neighbourhood-mediated shifts in tree biomass allocation drive overyielding in tropical species mixtures

Guillemot Joannès, Kunz Matthias, Schnabel Florian, Fichtner Andreas, Madsen Christopher P., Gebauer Tobias, Härdtle Werner, von Oheimb Goddert, Potvin Catherine. 2020. Neighbourhood-mediated shifts in tree biomass allocation drive overyielding in tropical species mixtures. New Phytologist, 228 (4) : 1256-1268.

Quartile : Outlier, Sujet : PLANT SCIENCES

Résumé : Variations in crown forms promote canopy space-use and productivity in mixed-species forests. However, we have a limited understanding on how this response is mediated by changes in within-tree biomass allocation. Here, we explored the role of changes in tree allometry, biomass allocation and architecture in shaping diversity–productivity relationships (DPRs) in the oldest tropical tree diversity experiment. We conducted whole-tree destructive biomass measurements and terrestrial laser scanning. Spatially explicit models were built at the tree level to investigate the effects of tree size and local neighbourhood conditions. Results were then upscaled to the stand level, and mixture effects were explored using a bootstrapping procedure. Biomass allocation and architecture substantially changed in mixtures, which resulted from both tree-size effects and neighbourhood-mediated plasticity. Shifts in biomass allocation among branch orders explained substantial shares of the observed overyielding. By contrast, root-to-shoot ratios, as well as the allometric relationships between tree basal area and aboveground biomass, were little affected by the local neighbourhood. Our results suggest that generic allometric equations can be used to estimate forest aboveground biomass overyielding from diameter inventory data. Overall, we demonstrate that shifts in tree biomass allocation are mediated by the local neighbourhood and promote DPRs in tropical forests.

Mots-clés Agrovoc : biomasse aérienne des arbres, allométrie, forêt tropicale, couvert forestier, productivité, biodiversité forestière, anatomie végétale, morphologie végétale, inventaire forestier

Mots-clés géographiques Agrovoc : Panama

Mots-clés libres : Biodiversity, Carbon sequestration, Ecosystem functioning, Forest productivity, Overyielding, Sardinilla experiment, Tree species diversity, Tropical plantation forest

Classification Agris : K10 - Production forestière

Champ stratégique Cirad : CTS 2 (2019-) - Transitions agroécologiques

Auteurs et affiliations

• Guillemot Joannès, CIRAD-PERSYST-UMR Eco&Sols (BRA) ORCID: 0000-0003-4385-7656 - auteur correspondant
• Kunz Matthias, Technische Universität Dresden (DEU)
• Schnabel Florian, University of Leipzig (DEU)
• Fichtner Andreas, University of Lüneburg (DEU)
• Madsen Christopher P., McGill University (CAN)
• Gebauer Tobias, Universität Freiburg (DEU)
• Härdtle Werner, University of Lüneburg (DEU)
• von Oheimb Goddert, Technische Universität Dresden (DEU)
• Potvin Catherine, McGill University (CAN)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/599673/)

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