Article dans une revue
Tree Physiology
Année : 2021
Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world’s highest elevation tree species
Tree growth is generally considered to be temperature limited at upper elevation treelines, yet climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polylepis tarapacana Philipi, the world’s highest elevation tree species, which is found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4400 m in elevation, along a 500 km latitude aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon sink processes along the gradient. Current growing-season temperature regulated RWI at northern-wetter sites, while prior growing-season precipitation determined RWI at arid southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site water availability. By contrast, warm and dry growing seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes along the gradient. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. This manuscript also highlights a coupling (decoupling) between physiological processes at leaf level and wood formation as a function of similarities (differences) in their climatic sensitivity. This study contributes to a better understanding and prediction of the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.
Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world’s highest elevation tree species
Résumé
en
Tree growth is generally considered to be temperature limited at upper elevation treelines, yet climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polylepis tarapacana Philipi, the world’s highest elevation tree species, which is found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4400 m in elevation, along a 500 km latitude aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon sink processes along the gradient. Current growing-season temperature regulated RWI at northern-wetter sites, while prior growing-season precipitation determined RWI at arid southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site water availability. By contrast, warm and dry growing seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes along the gradient. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. This manuscript also highlights a coupling (decoupling) between physiological processes at leaf level and wood formation as a function of similarities (differences) in their climatic sensitivity. This study contributes to a better understanding and prediction of the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.
Auteur(s)
Milagros Rodriguez-Caton
, Laia Andreu-Hayles
, Mariano S. Morales
, Valérie Daux1
, Duncan A. Christie
, Rafael Eduardo Coopman
, Claudio A. Alvarez
, Mukund Palat Rao
, Diego Aliste
, Felipe Flores
, Ricardo Villalba
1
LSCE -
Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
( 518 )
- Bât. 12,
avenue de la Terrasse,
F-91198 GIF-SUR-YVETTE CEDEX
- France
Université de Versailles Saint-Quentin-en-Yvelines UMR8212 ( 81173 )
;
Institut national des sciences de l'Univers UMR8212 ( 300045 )
;
Université Paris-Saclay ( 419361 )
;
Centre National de la Recherche Scientifique UMR8212 ( 441569 )
;
Direction de Recherche Fondamentale (CEA) ( 465913 )
;
Commissariat à l'énergie atomique et aux énergies alternatives ( 300016 )
Langue du document
Anglais
Nom de la revue
Tree Physiol -
Tree Physiology
(ISSN : 0829-318X, ISSN électronique : 1758-4469)
Publié par Oxford University Press (OUP)
Revue non référencée dans Sherpa-Romeo
Vulgarisation
Non
Comité de lecture
Oui
Audience
Internationale
Date de publication
2021
Volume
41
Numéro
8
Page/Identifiant
1353-1371
Domaine(s)
Sciences du Vivant [q-bio]/Sciences agricoles/Sylviculture, foresterie
Financement
15110009; INV 039-2019; National Science Foundation, NSF: AGS 1903687, AGS-1702789, OISE-1743738, PLR-1504134; Fondo Nacional de Desarrollo Científico y Tecnológico, FONDECYT: 1171640, 1201411; Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET: 11220130100584; Agencia Nacional de Promoción Científica y Tecnológica, ANPCyT: PICT 2013-1880, PICT 2018-03691
This research was supported by the project THEMES funded by Fondation BNP Paribas Climate Initiative program; United States National Science Foundation (OISE-1743738, PLR-1504134, AGS-1702789 and AGS 1903687); Lamont-Doherty Earth Observatory Climate Center; Columbia University?s Center for Climate and Life; Fondo Nacional de Desarrollo Cient?fico y Tecnol?gico (FONDECYT 1201411 and 1171640); Agencia Nacional de Investigaci?n y Desarrollo, Fondo de Financiamiento de Centros de Investigaci?n en ?reas Prioritarias (FONDAP 15110009); Agencia Nacional de Promoci?n Cient?fica y Tecnol?gica (PICT 2013-1880 and PICT 2018-03691); Consejo Nacional de Investigaciones Cient?ficas y T?cnicas de Argentina (PIP CONICET 11220130100584); Proyecto Fondo Nacional de Desarrollo Cient? fico, Tecnol?gico y de Innovaci?n Tecnol?gica a Banco Mundial (FONDECYT-BMINC. INV 039-2019).
Milagros Rodriguez-Caton, Laia Andreu-Hayles, Mariano S. Morales, Valérie Daux, Duncan A. Christie, et al.. Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world’s highest elevation tree species. Tree Physiology, 2021, 41 (8), pp.1353-1371. ⟨10.1093/treephys/tpab021⟩. ⟨hal-03401840⟩