Characterizing the Respiration of Stems and Roots of Three Hardwood Tree Species in the Great Smoky Mountains
Rakonczay Z. Characterizing the Respiration of Stems and Roots of Three Hardwood Tree Species in the Great Smoky Mountains. Virginia Polytechnic Institute and State University
ABSTRACT: Carbon dioxide efflux rates (CER) of stems and roots of overstory and understory black cherry (Prunus serotina Ehrh., BC), red maple (Acer rubrum L., RM) and northern red oak (Quercus rubra L., RO) trees were monitored over two growing seasons at two contrasting sites in the Great Smoky Mountains to investigate diurnal and seasonal patterns in respiration and to develop prediction models based on environmental and plant parameters. CER of small roots (d 10 cm) and twigs (d ±50%) deviations from the predictions. Deviations were higher in the canopy than in the understory. Mean bole maintenance respiration (at 20°C and d=20 cm) was 0.66, 0.43 and 0.50 μmol m-1, while the volume-based growth coefficient was around 5, 6 and 8 mol cm-3 for BC, RM and RO, respectively. In a controlled study, BC and RM seedlings were fumigated in open-top chambers with sub-ambient, ambient and twice-ambient levels of ozone. The twice-ambient treatment reduced stem CER in BC by 50% (p=0.05) in July, but there was no treatment effect in September or in RM. Ozone reduced root/shoot ratio and diameter growth in BC, and Pmax in both species.
- Type
- Academic
- Authors
- Rakonczay, Zoltán
- Publisher
- Virginia Polytechnic Institute and State University
- Units
- GRSM
- Keywords
- Acer rubrum, APHN, Appalachian Highlands Network, black cherry, Dissertation, Ecophysiology, Fine root respiration, Fractal dimension, Great Smoky Mountains National Park, GRSM, Maintenance coefficient, northern red oak, Prunus serotina, Quercus rubra, red maple, Sap flow, Scaling, SER, Southeast Region, trees, vascular plants