Interaction of ice storms and management practices on current carbon sequestration in forests with potential mitigation under future CO₂ atmosphere

Abstract

[1] Ice storms are disturbance events with potential impacts on carbon sequestration. Common forest management practices, such as fertilization and thinning, can change wood and stand properties and thus may change vulnerability to ice storm damage. At the same time, increasing atmospheric CO 2 levels may also influence ice storm vulnerability. Here we show that a nonintensively managed pine plantation experienced a $250 g C m À2reduction in living biomass during a single storm, equivalent to $30% of the annual net ecosystem carbon exchange of this ecosystem. Drawing on weather and damage survey data from the entire storm cell, the amount of C transferred from the living to the dead biomass pool (26.5 ± 3.3 Tg C), 85% of which will decompose within 25 years, was equivalent to $10% of the estimated annual sequestration in conterminous U.S. forests. Conifer trees were more than twice as likely to be killed as leafless deciduous broadleaf trees. In the Duke Forest case study, nitrogen fertilization had no effect on storm-induced carbon transfer from the living to detrital pool while thinning increased carbon transfer threefold. Elevated CO 2 (administered with the free-air CO 2 enrichment (FACE) system) reduced the storminduced carbon transfer to a third. Because of the lesser leaf area reduction, plots growing under elevated CO 2 also exhibited a smaller reduction in biomass production the following year. These results suggest that forests may suffer less damage during each ice storm event of similar severity in a future with higher atmospheric CO 2 .

Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

“…Our results also show that At the stand or regional level, NEE is significantly affected by disturbances (Law et al, 2004). Disturbances can substantially alter ecosystem carbon fluxes and regional carbon budgets (McCarthy et al, 2006;Chambers et al, 2007), by reducing the aboveground biomass and increase litter, thereby leading to a decrease in GPP and an increase in R h . Our results show that disturbances including wildfires and hurricanes could affect regional annual NEE.…”

Canopy leaf area constrains [CO 2 ]-induced enhancement of productivity and partitioning among aboveground carbon pools

“…1). This variation can be attributed to a number of causes: variations in water availability, the occurrence of a severe ice storm in December 2002 resulting in canopy damage and changes in sink dynamics (31), and changes in L D as the stand progressed to a closed canopy state ( When NPP and L D data were pooled across the four FACE sites [supporting information (SI) Table 1], after excluding the data from drought years and before canopy closure at Duke FACE, NPP was linearly related to L D ( Fig. 3A; n ϭ 40, P Ͻ 0.001 for both current and elevated [CO 2 ]; regression analysis was performed on single treatment-year data points, but we show treatment means and standard errors of each site) and significantly higher under elevated [CO 2 ] (P ϭ 0.039).…”

The Spatial Factor, Rather than Elevated CO 2 , Controls the Soil Bacterial Community in a Temperate Forest Ecosystem

“…Furthermore, it has been reported that slight topographical relief at the experimental site in Duke Forest generated a "treatment-similar" effect on plant productivity and C input to the soil (51,53,62), thus further disturbing the effects of CO 2 and N treatments. In addition, recent weather events contributed to increased spatial heterogeneity through uneven impact across the site (54). The resulting high heterogeneity of soil chemical properties makes it difficult to isolate the signal of the effect of elevated CO 2 or N amendment on soil bacterial diversity and community structure.…”