Premium
STABLE CARBON ISOTOPES AS INDICATORS OF LIMITATIONS TO FOREST GROWTH IMPOSED BY CLIMATE STRESS
Author(s) -
Panek Jeanne A.,
Waring Richard H.
Publication year - 1997
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1890/1051-0761(1997)007[0854:sciaio]2.0.co;2
Subject(s) - stomatal conductance , environmental science , humidity , atmospheric sciences , δ13c , carbon cycle , climate change , isotopes of carbon , ecology , stable isotope ratio , agronomy , total organic carbon , biology , botany , photosynthesis , ecosystem , geography , physics , quantum mechanics , geology , meteorology
Stable carbon isotopes have the potential to be sensitive indicators of carbon uptake limitations in forest trees. We assessed the ability of climate factors to explain the variation in δ 13 C in foliage and annual rings of Douglas‐fir trees at six sites along a steep climatic gradient in Oregon. To examine the physiological basis of the relationship between climate and δ 13 C, we parameterized a process‐level model (FOREST‐BGC) and used the model to separate the daily limitations on stomatal conductance due to climate factors. We found that, of the climatic constraints that could affect stomatal conductance (freezing temperature, humidity deficit, and soil drought), only the cumulative growing season constraints on stomata imposed by humidity deficit explained the variability in the carbon isotope composition of cellulose in foliage. Over an 8‐yr period at any one site, modelled stomatal limitation due to humidity deficit was significantly correlated with foliar δ 13 C. Over the same period, δ 13 C in annual growth rings was less well correlated with modelled stomatal constraints. This relation between δ 13 C and absolute humidity demonstrated the sensitivity of carbon uptake in Douglas‐fir, a species with a broad range across the intermountain West, to moisture at the leaf–atmosphere interface. Furthermore, the parameters derived from the relationship offer a baseline from which to assess limitations imposed on Douglas‐fir carbon uptake from sources other than climate.