Authors: Gyenge, J.¹; Fernández, M.²; Schlichter, T.³

Source: Trees, Volume 22, Number 4, August 2008 , pp. 483-490(8)

Publisher: Springer

Abstract:

Afforestation with the exotic Pinus ponderosa is currently taking place within the natural distributional area of Austrocedrus chilensis, a native conifer of N.W. Patagonia. Annual productivity of the exotic species is double the productivity of the native one. In order to test the hypothesis that these differences in productivity are, at least in part, due to differences in hydraulic characteristics of both species, we measured or estimated several ecophysiological variables in A. chilensis and P. ponderosa trees growing in the same place. Water use (WU) and diameter growth were lower in A. chilensis than in P. ponderosa. Although predawn water potential was relatively constant during the whole growing season, A. chilensis trees showed lower values of this variable than P. ponderosa in a very dry period, suggesting different water sources. Under field conditions, canopy-stomatal (gs) and whole hydraulic conductances, specific hydraulic conductivity and photosynthetic rate (A) were lower in A. chilensis than P. ponderosa. In contrast, instantaneous WU efficiency was higher in A. chilensis than in P. ponderosa. However, gs and A in A. chilensis significantly increased in cut branches of this species suggesting hydraulic limitations on photosynthesis. We hypothesize that hydraulic characteristics of P. ponderosa permit high stomatal conductance for more hours a day than A. chilensis trees, without reaching threshold values of water potential. This can explain, at least in part, differences in C fixation and thus, in productivity between species. In addition, our results suggested a secondary limitation to C fixation in A. chilensis at the photosynthetic apparatus.

Keywords: Drought avoidance; Forest replacement; Water relations; Stomatal conductance; Patagonia

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s00468-008-0208-9

Affiliations: 1: Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Bariloche, Argentina, Email: jgyenge@bariloche.inta.gov.ar 2: Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Bariloche, Argentina 3: Grupo Ecología Forestal, Estación Experimental Agropecuaria Bariloche INTA, CC 277 (8400), Bariloche, Argentina

Publication date: 2008-08-01

Related content

• In this: publication
• By this: publisher
• In this Subject: Forestry ,  Ecology
• By this author: Gyenge, J. ;  Fernández, M. ;  Schlichter, T.

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers