Response of central Siberian Scots pine to soil water deficit and long-term trends in atmospheric CO2 concentration

0206384 - UPB-H 20023028 RIV US eng J - Článek v odborném periodiku
Arneth, A. - Lloyd, J. - Šantrůčková, Hana - Bird, M. - Grigoryev, S. - Kalaschnikov, Y. N. - Gleixner, G. - Schulze, E. D.
Response of central Siberian Scots pine to soil water deficit and long-term trends in atmospheric CO2 concentration.
Global Biogeochemical Cycles. Roč. 16, č. 1 (2002), s. 1-13. ISSN 0886-6236. E-ISSN 1944-9224
Výzkumný záměr: CEZ:AV0Z6066911
Klíčová slova: stable isotopes * boreal forest * carbon cycle
Kód oboru RIV: EH - Ekologie - společenstva
Impakt faktor: 3.957, rok: 2002

Twenty tree ring 13C/12C ratio chronologies from Pinus sylvestris (Scots pine) trees were determined from five locations sampled along the Yenisei River, spaced over a total distance of ~1000 km between the cities of Turuhansk (66°N) and Krasnoyarsk (56°N). The transect covered the major part of the natural distribution of Scots pine in the region with median growing season temperatures and precipitation varying from 12,2°C and 218 mm to 14,0°C and 278 mm for Turuhansk and Krasnoyarsk, respectively. A key focus of the study was to investigate the effects of variations in temperature, precipitation, and atmospheric CO2 concentration on long- and short-term variation in photosynthetic 13C discrimination during photosynthesis and the marginal cost of tree water use, as reflected in the differences in the historical records of the 13C/12C ratio in wood cellulose compared to that of the atmosphere (D13Cc). In 17 of the 20 samples, trees D13Cc has declined during the last 150 years, particularly so during the second half of the twentieth century. Using a model of stomatal behaviour combined with a process-based photosynthesis model, we deduce that this trend indicates a long-term decrease in canopy stomatal conductance, probably in response to increasing atmospheric CO2 concentrations. This response being observed for most trees along the transect is suggestive of widespread decreases in D13Cc and increased water use efficiency for Scots pine in central Siberia over the last century. Overlying short-term variations in D13Cc were also accounted for by the model and were related to variations in growing season soil water deficit and atmospheric humidity.
Trvalý link: http://hdl.handle.net/11104/0101978