Are leaf, stem and hydraulic traits good predictors of individual tree growth?
Rosas, Teresa (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Mencuccini, Maurizio (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Batlles, Carles (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Regalado, Íngrid (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Saura Mas, Sandra (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Sterck, Frank (Wageningen University and Research Centre)
Martínez Vilalta, Jordi 1975- (Centre de Recerca Ecològica i d'Aplicacions Forestals)

Date:	2021
Abstract:	A major foundation of trait-based ecology is that traits have an impact on individual performance. However, trait-growth relationships have not been extensively assessed in trees, especially outside tropical ecosystems. In addition, measuring traits directly related to physiological processes remains difficult and the differences between inter- and intraspecific relationships are seldom explored. Here, we use individual-level data on a set of hydraulic, leaf and stem traits to assess their ability to predict basal area increment (BAI) and growth efficiency (BAI per unit of tree leaf area, GE) among and within species for six dominant tree species along a water availability gradient under Mediterranean climate (Catalonia, NE Spain). Measured traits include: leaf mass per area (LMA), leaf nitrogen concentration (N), leaf C isotopic composition (δC), the leaf water potential at turgor loss (P), stem wood density (WD) and branch-level estimates of the Huber value (Hv), sapwood- and leaf-specific hydraulic conductivity (K and K) and resistance to xylem embolism (P). Trait-growth associations were generally weak, particularly for BAI and within species. High values of both growth metrics were associated with 'conservative' leaf and hydraulic traits. In particular, BAI was negatively associated with K (and wood density), while GE increased with LMA, allocation to sapwood relative to leaves (Hv) and resistance to xylem embolism (P). Climate effects on BAI and GE were indirectly mediated by changes in traits, stand structure and tree basal area. Overall, these results suggest that maintaining functionality over extended periods of time may be more important than maximum gas exchange or hydraulic capacity to achieve high radial growth under Mediterranean climates. Our study reveals that widely used 'functional traits' may be poor predictors of tree growth variability along environmental gradients. Moreover, trait effects (when present) do not necessarily conform to simple hypotheses based on our understanding of organ-level processes. An improved understanding of trait coordination along common axes of variation together with a revaluation of the variables that better reflect whole-tree performance can greatly improve our understanding of trait-growth relationships. A free Plain Language Summary can be found within the Supporting Information of this article.
Grants:	Ministerio de Economía y Competitividad CGL2013-46808-R Agencia Estatal de Investigación CGL2017-89149-C2-1-R
Note:	Altres ajuts: acords transformatius de la UAB
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Basal area increment ; Functional trait ; Growth efficiency ; Hydraulics ; Intraspecific variability ; Leaf economic spectrum ; Water availability
Published in:	Functional ecology, Vol. 35, Issue 11 (November 2021) , p. 2435-2447, ISSN 1365-2435

DOI: 10.1111/1365-2435.13906

13 p, 2.0 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Articles > Research articles
Articles > Published articles