title: Stem CO2 efflux in six co-occurring tree species: underlying factors and ecological implications.
abstract: Stem respiration plays a role in species coexistence and forest dynamics. Here we examined the intra- and inter-specific variability of stem CO2 efflux (E) in dominant and suppressed trees of six deciduous species in a mixed forest stand: Fagus sylvatica L., Quercus petraea [Matt.] Liebl, Quercus pyrenaica Willd., Prunus avium L., Sorbus aucuparia L. and Crataegus monogyna Jacq. We conducted measurements in late autumn. Within species, dominants had higher E per unit stem surface area (Es ) mainly because sapwood depth was higher than in suppressed trees. Across species, however, differences in Es corresponded with differences in the proportion of living parenchyma in sapwood and concentration of non-structural carbohydrates (NSC). Across species, Es was strongly and NSC marginally positively related with an index of drought tolerance, suggesting that slow growth of drought-tolerant trees is related to higher NSC concentration and Es . We conclude that, during the leafless period, E is indicative of maintenance respiration and is related with some ecological characteristics of the species, such as drought resistance; that sapwood depth is the main factor explaining variability in Es within species; and that the proportion of NSC in the sapwood is the main factor behind variability in Es among species.
authors.affiliation: Forest Genetics and Ecophysiology Research Group, School of Forestry Engineering, Technical University of Madrid, Madrid, 28040, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Rodríguez-Calcerrada
authors.forename: Rosana
authors.initials: R
authors.lastname: López
authors.forename: Roberto
authors.initials: R
authors.lastname: Salomón
authors.forename: Guillermo G
authors.initials: GG
authors.lastname: Gordaliza
authors.forename: María
authors.initials: M
authors.lastname: Valbuena-Carabaña
authors.forename: Jacek
authors.initials: J
authors.lastname: Oleksyn
authors.forename: Luis
authors.initials: L
authors.lastname: Gil
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D027825:Crataegus / Q000378:metabolism / Q000502:physiology; D004463:Ecology; D029964:Fagus / Q000378:metabolism / Q000502:physiology; D018547:Plant Stems / Q000378:metabolism / Q000502:physiology*; D000068220:Prunus avium / Q000378:metabolism / Q000502:physiology; D029963:Quercus / Q000378:metabolism / Q000502:physiology; D031994:Sorbus / Q000378:metabolism / Q000502:physiology; D014197:Trees / Q000378:metabolism / Q000502:physiology*
chemical_list: D002245:Carbon Dioxide
keywords: carbon balance; forest succession; shade tolerance; tree canopy class; tree survival; xylem live cell content