Soil CO2 efflux in loblolly pine (Pinus taeda L.) plantations on the Virginia Piedmont and South Carolina Coastal Plain over a rotation-length chronosequence

Abstract

We measured soil surface CO 2 efflux (F s ) in loblolly pine stands (Pinus taeda L.) located on the Virginia Piedmont (VA) and South Carolina Coastal Plain (SC) in efforts to assess the impact climate, productivity, and cultural practices have on F s in the managed loblolly pine ecosystem. The effect of stand age on F s was examined using a replicated chronosequence approach in which stands ranging from 1 to 25 years since planting were investigated. Soil CO 2 efflux was measured on both VA and SC sites for over a year using a closed dynamic system. Multiple linear regression was used to evaluate F s correlates and examine the relationship between candidate explanatory variables and F s . Soil temperature (top 10 cm) was the major correlate with F s on both locations. We observed a positive age effect on F s in VA stands and no relationship between age and F s in SC stands. Annual soil C efflux declined with stand age in SC due to both reductions in soil temperatures as crown closure occurs and a diminishing heterotrophic C substrate pool. Annual estimated efflux ranges from 16.7 to 13.2 Mg C ha À1 for 1 and 20-year-old stands, respectively. In contrast, annual soil C efflux increased with age in VA stands as a result of the positive relationship between stand age and F s , which appears to be related to an increase in the contribution of root respiration to total F s over time. In VA stands, efflux estimates range from 7.6 to 12.3 Mg C ha À1 for 1 and 20-year-old stands, respectively. These results demonstrate the need to further consider the impact forest management and within-region variability have on soil C efflux over time when estimating C budgets.

Long-term effects of site preparation and fertilization on total soil CO2 efflux and heterotrophic respiration in a 33-year-old Pinus taeda L. plantation on the wet flats of the Virginia Lower Coastal Plain

“…Our estimates of total soil CO 2 efflux ranged from 2.1 to 12.1 mmol CO 2 m À2 s À1 and were consistent with rates measured by others for mature loblolly pine stands (Selig, 2003;Wiseman and Seiler, 2004;Butnor et al, 2005;Gough et al, 2005). Perhaps because of the limited range in soil temperature during this study, temperature explained very little of the variation in F S or R H .…”

“…Site preparation (i.e., ditching and bedding) can lead to improved soil aeration, seedling survival, and accelerate early growth (Burger and Pritchett, 1988;Andrews, 1993;Allen and Lein, 1998;Wheeler et al, 2002;Miwa et al, 2004). Short-term site preparation treatments, such as bedding, can provide an enhanced soil environment (aeration, temperature, and moisture) as well as incorporate OM into the mineral soil, leading to increased decomposition of soil OM, and, consequently, increased F S and R H in the years immediately following site preparation (Ewel et al, 1987;Trettin et al, 1996;Gough et al, 2005). www.elsevier.com/locate/foreco Forest Ecology and Management 234 (2006) [363][364][365][366][367][368][369] Pine plantations in the Southeastern United States currently comprise approximately 13 million ha, and are forecasted to increase to about 22 million ha by 2040 (Wear and Greis, 2002).…”

Forest Floor and Mineral Soil Respiration Rates in a Northern Minnesota Red Pine Chronosequence

“…Although theory predicts a possible decline in R S from middle-aged to older forests [12], several studies have reported positive relationships between stand age and soil respiration rates spanning various stages of forest development [6,13,16,17]. We found no evidence of either of these patterns, but we did find that soil respiration rates were often lower in Y31 than in the other stands during the middle of the growing season, particularly in July and August when soil temperatures were highest.…”

Soil CO2 Efflux and Root Productivity in a Switchgrass and Loblolly Pine Intercropping System

“…A study by Gough et al [34] reported seasonal R S rates between 1 and 5 µmol CO 2 m −2 ·s −1 in a four-year-old loblolly pine stand on the Virginia Piedmont. Another study by Wiseman and Seiler [35] reported maximum R S of 4 µmol CO 2 m −2 ·s −1 in 1-to 2-year-old loblolly pine stands and 7 µmol CO 2 m −2 ·s −1 in 20-to 25-year-old loblolly pine stands located on the Virginia Piedmont.…”