Environmental Controls over Net Exchanges of Carbon Dioxide from Contrasting Florida Ecosystems

Clark, Kenneth L.; Gholz, Henry L.; Moncrieff, John; Cropley, Ford; Loescher, Henry W.

doi:10.2307/2641340

Cited by 35 publications

(66 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Annual R eco increased with GEE over the study period at each site. Recently assimilated carbohydrates fuel approximately 50% of the biological activity in soil [67], [68], and in many conifer forest ecosystems, R eco tends to be dominated by soil respiration [43], [69], [70], [71]. In comparison to the xeric site, higher GEE at the mesic and intermediate sites likely resulted in increased R eco .…”

Section: Discussionmentioning

confidence: 99%

“…Flux data screening was applied to eliminate 30-min fluxes resulting from systematic errors such as: i ) rain and condensation in the sampling path, ii ) incomplete 30-min datasets during system calibration or maintenance, iii ) poor coupling of the canopy with the external atmospheric conditions, as defined by the friction velocity, u*, using a threshold <0.20 m s −1 [43], [44], and iv ) excessive variation from the half-hourly mean based on an analysis of standard deviations for u, v , and w wind and CO 2 statistics. Quality assurance of the flux data was also maintained by examining plausibility tests ( i.e ., NEE<−30 and NEE >30 µmol m −2 s −1 ), stationarity criteria, and integral turbulent statistics [45], [46].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Cyclic Occurrence of Fire and Its Role in Carbon Dynamics along an Edaphic Moisture Gradient in Longleaf Pine Ecosystems

et al. 2013

View full text Add to dashboard Cite

Fire regulates the structure and function of savanna ecosystems, yet we lack understanding of how cyclic fire affects savanna carbon dynamics. Furthermore, it is largely unknown how predicted changes in climate may impact the interaction between fire and carbon cycling in these ecosystems. This study utilizes a novel combination of prescribed fire, eddy covariance (EC) and statistical techniques to investigate carbon dynamics in frequently burned longleaf pine savannas along a gradient of soil moisture availability (mesic, intermediate and xeric). This research approach allowed us to investigate the complex interactions between carbon exchange and cyclic fire along the ecological amplitude of longleaf pine. Over three years of EC measurement of net ecosystem exchange (NEE) show that the mesic site was a net carbon sink (NEE = −2.48 tonnes C ha−1), while intermediate and xeric sites were net carbon sources (NEE = 1.57 and 1.46 tonnes C ha−1, respectively), but when carbon losses due to fuel consumption were taken into account, all three sites were carbon sources (10.78, 7.95 and 9.69 tonnes C ha−1 at the mesic, intermediate and xeric sites, respectively). Nonetheless, rates of NEE returned to pre-fire levels 1–2 months following fire. Consumption of leaf area by prescribed fire was associated with reduction in NEE post-fire, and the system quickly recovered its carbon uptake capacity 30–60 days post fire. While losses due to fire affected carbon balances on short time scales (instantaneous to a few months), drought conditions over the final two years of the study were a more important driver of net carbon loss on yearly to multi-year time scales. However, longer-term observations over greater environmental variability and additional fire cycles would help to more precisely examine interactions between fire and climate and make future predictions about carbon dynamics in these systems.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Cyclic Occurrence of Fire and Its Role in Carbon Dynamics along an Edaphic Moisture Gradient in Longleaf Pine Ecosystems

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The two sites used in this study are both commercial slash pine plantations, located ;15 km northeast of Gainesville, Florida, USA, and managed for pulpwood production (Clark et al 1999. The first site (Mize Tract, MT; 29845.888 0 N, 82814.689 0 W) was established following the stem-only harvest in 1998 of a 25-year-old plantation (Clark et al 1999(Clark et al , 2004.…”

Section: Study Sitesmentioning

confidence: 99%

“…The clearcut was bedded (treated with a plow that produces raised planting beds, which improves drainage, reduces competition, and improves seedling survival (VanderSchaaf andSouth 2004, Fox et al 2007), treated with a combination of imazapyr and triclopyr herbicide to reduce competition from both woody and herbaceous weeds, and replanted at ;1800 trees/ha in December 1998-January 1999. The second site (Donaldson Tract, DT; 29845.286 0 N, 82809.797 0 W) was established in a plantation that was eight years old in 1998 (Clark et al 1999(Clark et al , 2004. The second site (Donaldson Tract, DT; 29845.286 0 N, 82809.797 0 W) was established in a plantation that was eight years old in 1998 (Clark et al 1999(Clark et al , 2004.…”

Section: Study Sitesmentioning

confidence: 99%

“…However, much of the earlier research on the carbon dynamics of slash pine plantations was conducted during short (,3 year) periods with abundant precipitation (e.g., Ewel et al 1987a, b, Cropper and Gholz 1993, Fang et al 1998, Clark et al 1999. In fact, Teskey et al (1994) concluded that mature slash pine trees in Florida showed no significant response of canopy conductance to vapor pressure deficits associated with normal seasonal drought, and Neary et al (1990) found that young slash pine and loblolly pine (P. taeda) stands showed no response to irrigation treatments.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Controls on carbon dynamics by ecosystem structure and climate for southeastern U.S. slash pine plantations

Bracho

Starr

Gholz

et al. 2012

Ecological Monographs

Self Cite

View full text Add to dashboard Cite

Planted pine forests (plantations) in the southeastern United States are an important component of the continent's carbon balance. Forest carbon dynamics are affected by a range of factors including climatic variability. Multiyear droughts have affected the region in the past, and an increase in the frequency of drought events has been predicted. How this increased climatic variability will affect the capacity of the region's pine plantations to sequester carbon is not known. We used eddy covariance and biometric approaches to measure carbon dynamics over nine years in two slash pine plantations (Pinus elliottii var elliottii Englm) in north Florida, consisting of a newly planted and a mid-rotation stand. During this time, the region experienced two multiyear droughts (1999-2002 and 2006-2008), separated by a three-year wet period. Net ecosystem carbon accumulation measured using both approaches showed the same trends and magnitudes during plantation development. The newly planted site released 15.6 Mg C/ha during the first three years after planting, before becoming a carbon sink in year 4. Increases in carbon uptake during the early stages of stand development were driven by the aggrading leaf area index (LAI). After canopy closure, both sites were continuous carbon sinks with net carbon uptake (NEE) fluctuating between 4 and ;8 Mg CÁha À1 Áyr À1 , depending on environmental conditions. Drought reduced NEE by ;25% through its negative effects on both LAI and radiation-use efficiency, which resulted in a larger impact on gross ecosystem carbon exchange than on ecosystem respiration. While results indicate that responses to drought involved complex interactions among water availability, LAI, and radiation-use efficiency, these ecosystems remain carbon sinks under current management strategies and climatic variability. Variation within locations is primarily due to major disturbances, such as logging in the current study and, to a much lesser extent, local environmental fluctuations. When data from this study are compared to flux data from a broad range of forests worldwide, these ecosystems fill a data gap in the warm-temperate zone and support a broad maximum NEE (for closed-canopy forests) between 88C and 208C mean annual temperature.

show abstract

Seasonal patterns in energy partitioning of two freshwater marsh ecosystems in the Florida Everglades

Malone

Staudhammer

Loescher

et al. 2014

J. Geophys. Res. Biogeosci.

Self Cite

View full text Add to dashboard Cite

We analyzed energy partitioning in short-and long-hydroperiod freshwater marsh ecosystems in the Florida Everglades by examining energy balance components (eddy covariance derived latent energy (LE) and sensible heat (H) flux). The study period included several wet and dry seasons and variable water levels, allowing us to gain better mechanistic information about the control of and changes in marsh hydroperiods. The annual length of inundation is~5 months at the short-hydroperiod site (25°26′16.5″N, 80°35′40.68″W), whereas the long-hydroperiod site (25°33′6.72″N, 80°46′57.36″W) is inundated for~12 months annually due to differences in elevation and exposure to surface flow. In the Everglades, surface fluxes feed back to wet season precipitation and affect the magnitude of seasonal change in water levels through water loss as LE (evapotranspiration (ET)). At both sites, annual precipitation was higher than ET (1304 versus 1008 at the short-hydroperiod site and 1207 versus 1115 mm yr À1 at the long-hydroperiod site), though there were seasonal differences in the ratio of ET:precipitation. Results also show that energy balance closure was within the range found at other wetland sites (60 to 80%) and was lower when sites were inundated (60 to 70%). Patterns in energy partitioning covaried with hydroperiods and climate, suggesting that shifts in any of these components could disrupt current water and biogeochemical cycles throughout the Everglades region. These results suggest that the complex relationships between hydroperiods, energy exchange, and climate are important for creating conditions sufficient to maintain Everglades ecosystems.

show abstract

Environmental Controls over Net Exchanges of Carbon Dioxide from Contrasting Florida Ecosystems

Cited by 35 publications

References 0 publications

Cyclic Occurrence of Fire and Its Role in Carbon Dynamics along an Edaphic Moisture Gradient in Longleaf Pine Ecosystems

Cyclic Occurrence of Fire and Its Role in Carbon Dynamics along an Edaphic Moisture Gradient in Longleaf Pine Ecosystems

Controls on carbon dynamics by ecosystem structure and climate for southeastern U.S. slash pine plantations

Seasonal patterns in energy partitioning of two freshwater marsh ecosystems in the Florida Everglades

Contact Info

Product

Resources

About