Spatial and temporal variability of soil CO2 efflux in three proximate temperate forest ecosystems

• Published in: Agricultural and forest meteorology 2013-04, Vol.171-172, p.256-269
• Main Authors: Oishi, A. Christopher, Palmroth, Sari, Butnor, John R., Johnsen, Kurt H., Oren, Ram
• Format: Article
• Language: English
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agronomy. Soil science and plant productions; Animal and plant ecology; Animal, plant and microbial ecology; Automated soil respiration chambers; Belowground carbon flux; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Deciduous; Drought; Evergreen; Flux; forest ecosystems; Forest Science; Forests; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; hardwood; leaf area; leaves; Litterfall; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Pinus taeda; Polypropylenes; primary productivity; Productivity; sandy soils; Skogsvetenskap; Soil (material); soil heterogeneity; soil respiration; Soil science; Soil temperature; soil water; Stands; Supports; Synecology; temperate forests; temporal variation
• ISSN: 0168-1923; 1873-2240; 1873-2240
• DOI: 10.1016/j.agrformet.2012.12.007

► Soil CO2 flux (Fsoil) was measured with automated systems over a 10-year period. ► Fsoil varied seasonally with temperature and interannually with soil moisture. ► Among stands, temperature-sensitivity of Fsoil increased with leaf production. ► Within a stand, leaf area affected temperature and carbon allocation. ► Fsoil showed opposing relationships with leaf production among and between stands. The magnitude of CO2 flux from soil (Fsoil) varies with primary productivity and environmental drivers of respiration, soil temperature (Tsoil) and moisture, all of which vary temporally and spatially. To quantify the sources of Fsoil variability, we first compared Fsoil of three proximate forests within 30km of one another, ranging in age, composition, soil, and environment and, thus, productivity. We collected data with automated soil respiration chambers during a 10-year period in a mid-rotation Pinus taeda plantation (PP), for three-years in a mature P. taeda stand (OP), and for five-years in a mature, mixed-species hardwood (HW) stand; PP and HW were on clay-loam soil and OP on a sandy soil. Among stands, Fsoil sensitivity to Tsoil was lowest in OP and highest in PP, reflected in mean annual Fsoil (±standard deviation) of 1033±226 (OP), 1206±99 (HW), and 1383±152 (PP)gCm−2; both Fsoil sensitivity to Tsoil and annual Fsoil increased with leaf litterfall. For the second portion of our study, we established an additional three plots at PP for a six-year period to examine within-stand variability. Within PP, sensitivity of Fsoil to Tsoil was similar, yet higher leaf area was correlated with a combination of lower soil temperature and belowground carbon flux, resulting in lower Fsoil. Temporally, diurnal to seasonal Fsoil followed Tsoil whereas annual values were driven by soil moisture. Spatially, among the three stands Fsoil increased with leaf production, whereas within a stand (PP) Fsoil decreased with increasing leaf production.