title: 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.
authors: USDA Forest Service Northern Research Station, 1831 Highway 169 East, Grand Rapids, Minnesota 55744, USA. mdpowers@mtu.edu
authors: Matthew D
authors: MD
authors: Powers
authors: Randall K
authors: RK
authors: Kolka
authors: John B
authors: JB
authors: Bradford
authors: Brian J
authors: BJ
authors: Palik
authors: Shawn
authors: S
authors: Fraver
authors: Martin F
authors: MF
authors: Jurgensen
mesh_terms: D002244:Carbon / Q000737:chemistry / Q000378:metabolism*; D057486:Carbon Cycle; D017753:Ecosystem; D016468:Forestry / Q000379:methods*; D008910:Minnesota; D028223:Pinus / Q000502:physiology*; D012987:Soil / Q000737:chemistry; D013997:Time Factors; D014197:Trees / Q000502:physiology
chemical_list: D012987:Soil; D002244:Carbon