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WHOLE-SEEDLING BIOMASS ALLOCATION, LEAF AREA, AND TISSUE CHEMISTRY FOR DOUGLAS-FIR EXPOSED TO ELEVATED CO2 AND TEMPERATURE FOR 4 YEARS
Citation:
Olszyk, D M., M G. Johnson, D T. Tingey, P T. Rygiewicz, C M. Wise, E. Van Ess, A. Benson, M. Storm, AND R. King. WHOLE-SEEDLING BIOMASS ALLOCATION, LEAF AREA, AND TISSUE CHEMISTRY FOR DOUGLAS-FIR EXPOSED TO ELEVATED CO2 AND TEMPERATURE FOR 4 YEARS. CANADIAN JOURNAL OF FOREST RESEARCH. NRC Research Press, Ottawa, Canada, 33:269-278, (2003).
Description:
Changes in the global climate may impact forests, but data are lacking for climate change effects on whole tree productivity over multiple seasons and conditions representative of the field. To address this critical need, we measured biomass allocation for whole Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir) seedlings treated with ambient or elevated (+180 mol mol-1) CO2 and with ambient or elevated (+3.5 C) temperature. Seedings were grown for four years in outdoor, sun-lit, chambers under a wet-winter/dry-summer soil moisture regime and without added fertilization. At the end of the experiment, whole seedlings were harvested to determine biomass and area of leaves, biomass of fine roots (<1 mm diameter), and biomass of the remaining structural components (buds, branches, stems, main root, lateral roots >1 mm in diameter). Elevated CO2 decreased leaf area relative to leaf biomass or whole plant biomass at p<0.10, but had no other significant effects on either whole tree or individual component biomass, % biomass allocation or leaf area. Elevated temperature reduced the allocation of biomass to leaves relative to the whole plant (p<0.10), but had no other significant effects on whole tree biomass, biomass allocation, or ratios among organ weights and leaf area. No significant interactions occurred between CO2 and temperature for any tree biomass parameters. Therefore, for Pseudotsuga menziesii trees growing under natural soil moisture and nutrition conditions, elevated temperature may have little impact on seedling biomass except for reduced allocation to leaves and elevated CO2 may only increase leaf biomass relative to area.