Characterizing above- and belowground carbon partitioning in forest trees along an altitudinal gradient using area-based indicators

• Published in: Arctic, Antarctic, and Alpine Research
• Main Authors: Mao, Zhun, Wang, Yan, Jourdan, Christophe, Cécillon, Lauric, Nespoulous, Jérome, Rey, Hervé, Saint-André, Laurent, Stokes, Alexia
• Other Authors: Ecosystèmes montagnards (UR EMGR), Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD France-Sud ), Ecologie fonctionnelle et biogéochimie des sols et des agro-écosystèmes (UMR Eco&Sols), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA), Unité de recherche Biogéochimie des Ecosystèmes Forestiers (BEF), Institut National de la Recherche Agronomique (INRA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDV.SA]Life Sciences [q-bio]/Agricultural sciences; [SDV.BV]Life Sciences [q-bio]/Vegetal Biology; Antarctic and Alpine Research; Arctic; Arctic and Alpine Research
• Online Access: https://hal.archives-ouvertes.fr/hal-01268890; https://doi.org/10.1657/AAAR0014-014

Characterizing the above- and belowground carbon stocks of ecosystems is vital for a better understanding of the role of vegetation in carbon cycling. Yet studies on forest ecosystems at high altitudes remain scarce. We examined above- and belowground carbon partitioning in trees growing in mixed montane/upper montane forest ecosystems in the French Alps. Field work was performed in three forests along a gradient of both altitude (1400 m, 1700 m, and 2000 m) and altitude-induced species composition (from lower altitude Abies alba and Fagus sylvatica to higher altitude Picea abies and Pinus uncinata). We performed forest inventories and root sampling along soil wall profiles, so that the stand basal area (SBA, in m2 ha-1) and root cross-sectional area (RCSA, in m2 ha-1) were estimated at each altitude. To characterize the carbon allocation trend between the above-and belowground compartments, the ratio of RCSA to SBA was then calculated. We found that both SBA and RCSA of coarse roots (diameter > 2 mm) were significantly different among the three altitudes. No significant difference in RCSA of fine roots (diameter ≤ 2 mm) was found among altitudes. The ratio of RCSA of fine roots to SBA augmented with increasing elevation, suggesting that forest ecosystems at higher altitudes allocate more carbon from above- to belowground organs. This increased allocation to fine roots would allow trees to scavenge nutrients more efficiently throughout the short growing season. Furthermore, this work highlighted the interest of using easy to measure area-based indicators as proxies of root and stem biomass when investigating carbon partitioning in highly heterogeneous montane/upper montane forests.