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Leaf δ 18 O of remaining trees is affected by thinning intensity in a semiarid pine forest
Author(s) -
MORENOGUTIÉRREZ CRISTINA,
BARBERÁ GONZALO G.,
NICOLÁS EMILIO,
DE LUIS MARTÍN,
CASTILLO VÍCTOR M.,
MARTÍNEZFERNÁNDEZ FAUSTINO,
QUEREJETA JOSÉ I.
Publication year - 2011
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2011.02300.x
Subject(s) - thinning , stomatal conductance , photosynthesis , water use efficiency , transpiration , competition (biology) , environmental science , botany , horticulture , agronomy , biology , ecology
Silvicultural thinning usually improves the water status of remaining trees in water‐limited forests. We evaluated the usefulness of a dual stable isotope approach ( δ 13 C, δ 18 O) for comparing the physiological performance of remaining trees between forest stands subjected to two different thinning intensities (moderate versus heavy) in a 60‐year‐old Pinus halepensis Mill. plantation in semiarid southeastern Spain. We measured bulk leaf δ 13 C and δ 18 O, foliar elemental concentrations, stem water content, stem water δ 18 O ( δ 18 O stem water ), tree ring widths and leaf gas exchange rates to assess the influence of forest stand density on tree performance. Remaining trees in low‐density stands (heavily thinned) showed lower leaf δ 18 O, and higher stomatal conductance ( g s ), photosynthetic rate and radial growth than those in moderate‐density stands (moderately thinned). By contrast, leaf δ 13 C, intrinsic water‐use efficiency, foliar elemental concentrations and δ 18 O stem water were unaffected by stand density. Lower foliar δ 18 O in heavily thinned stands reflected higher g s of remaining trees due to decreased inter‐tree competition for water, whereas higher photosynthetic rate was largely attributable to reduced stomatal limitation to CO 2 uptake. The dual isotope approach provided insight into the early (12 months) effects of stand density manipulation on the physiological performance of remaining trees.