Carbon stocks across a chronosequence of thinned and unmanaged red pine (Pinus resinosa) stands

Abstract

Forests function as a major global C sink, and forest management strategies that maximize C stocks offer one possible means of mitigating the impacts of increasing anthropogenic CO2 emissions. We studied the effects of thinning, a common management technique in many forest types, on age-related trends in C stocks using a chronosequence of thinned and unmanaged red pine (Pinus resinosa) stands ranging from 9 to 306 years old. Live tree C stocks increased with age to a maximum near the middle of the chronosequence in unmanaged stands, and increased across the entire chronosequence in thinned stands. C in live understory vegetation and C in the mineral soil each declined rapidly with age in young stands but changed relatively little in middle-aged to older stands regardless of management. Forest floor C stocks increased with age in unmanaged stands, but forest floor C decreased with age after the onset of thinning around age 40 in thinned stands. Deadwood C was highly variable, but decreased with age in thinned stands. Total ecosystem C increased with stand age until approaching an asymptote around age 150. The increase in total ecosystem C was paralleled by an age-related increase in total aboveground C, but relatively little change in total belowground C. Thinning had surprisingly little impact on total ecosystem C stocks, but it did modestly alter age-related trends in total ecosystem C allocation between aboveground and belowground pools. In addition to characterizing the subtle differences in C dynamics between thinned and unmanaged stands, these results suggest that C accrual in red pine stands continues well beyond the 60-100 year management rotations typical for this system. Management plans that incorporate longer rotations and thinning in some stands could play an important role in maximizing C stocks in red pine forests while meeting other objectives including timber extraction, biodiversity conservation, restoration, and fuel reduction goals.

Forest Carbon Sequestration: The Impact of Forest Management

“…The Nave et al, (2010) meta-analysis found that harvesting reduced soil carbon stocks in a small but significant way: forest floor carbon stocks decreased markedly and no influence was detected in the mineral soil, though great variation was identified between soil orders. This forest floor carbon stock reduction tendency for thinned stands is corroborated by several studies (e.g., Vesterdal et al, 1995;Jonard et al, 2006;Powers et al, 2012;Ruiz-Peinado et al, 2013), though other authors have reported little or no influence (Novák and Slodicák, 2004;Chatterjee et al, 2009;Jurgensen et al, 2012).…”

“…In a chronosequence study on Pinus resinosa, Powers et al, (2012) found that thinning did not have a significant effect on total ecosystem carbon stock. However, in a previous study of the same species, Powers et al, (2011) found that thinning reduced the total carbon stock when these treatments were applied at 5-10 year interval.…”

Impact of thinning on carbon storage of dead organic matter across larch and oak stands in South Korea

“…Since forests act as the principal C storage system in terrestrial ecosystems and are sensitive to anthropogenic activity, appropriate forest management is considered important for C sequestration (Boerner et al 2008, Powers et al 2012. Thinning treatment, which is selective logging to enhance the value of forests, is known to alter the forest C storage by reducing the standing tree density and stimulating growth of the remaining trees (Zhou et al 2013).…”

“…Dead organic matter, which originates from living organisms, accounts for approximately half of the forest C storage (Boerner et al 2008, Powers et al 2012. Fallen leaves, branches, and coarse woody debris (CWD) are the primary forms of dead organic matter, whose quantity and quality are related to the succession stage and forest management (Powers et al 2012, Ko et al 2014.…”

“…Fallen leaves, branches, and coarse woody debris (CWD) are the primary forms of dead organic matter, whose quantity and quality are related to the succession stage and forest management (Powers et al 2012, Ko et al 2014. Mineral soil stores a large volume of organic C derived from the primary forms of dead organic matters.…”