Growth and transpiration of Norway spruce trees under atmosphere with elevated CO2 concentration

The measurements were carried out on thirteen-year-old Norway spruce (Picea abies [L.] K a r s t.) trees grown in different stand densities at ambient (A, 350 mu mol(CO2)mol(-1)) and elevated (E, A+350 mu mol(CO2)mol(-1)) CO2 concentrations inside some domes (experimental equipment for simulation of elevated CO2 concentration in atmosphere), and on the control plot (C). Al l measurements were performed at the Experimental Study Site Bily Kriz in t he Beskydy Mts (the Czech Republic) during three growing seasons. The objec tives of this study were to determine the influence of elevated CO, concent ration on growth and transpiration due to differences between variants in: (1) buds germination, (2) height and diameter increments of trees, (3) abov eground biomass increment, (4) specific leaf area, (5) structural character istics of shoots, and (6) specific sap flux and total sap flux. No statistically significant differences were found in bud phenology, heigh t increment and aboveground biomass increment between A and E variants wher e trees were grown at difficult stand densities. positive effect of elevate d CO2 on tree diameter increment arises the 3(rd) year of experiment durati on in the sparse stand. parameters of needles and shoots in elevated treatm ent were close to "shaded type" ones. Sap flux data allowed a high variabil ity among the individual trees and during the growing season independently on location, within the sub-variant. Moreover, no difference was found in t ranspiration data between corresponding ambient and elevated subvariants, e xcept the stand transpiration of dense sub-variants in late summer (Septemb er).