Defense Date

2021

Document Type

Thesis

Degree Name

Master of Science

Department

Biology

First Advisor

Christopher Gough

Abstract

Managing forests for carbon (C) sequestration requires an understanding of how disturbance history shapes C pools and fluxes over successional time. At the University of Michigan Biological Station, we examined how two stand establishing disturbances influenced C pools and fluxes over 100+ years of succession, comparing these secondary forests with “legacy” late-successional stands encompassing ages and compositions that would be present in the absence of region-wide stand-replacing disturbance. Our work utilized measurements taken between 2014 and 2020 from separate experimental forest chronosequences initiated following clear-cut harvesting only or clear-cut harvesting and fire, along with three >130-yr-old late successional stands comprising deciduous broadleaf, evergreen needleleaf, and mixed forest functional types. Net primary production (NPP) was relatively similar regardless of stand age and establishing disturbance, averaging 4.95 Mg C ha-1 yr-1, while heterotrophic soil respiration (Rsh) increased with age in the cut and burn chronosequence. The C pool and flux values of late successional stands varied by plant functional type, while total C pools averaged higher (271.78 Mg C ha-1) than those of chronosequence stands (140.45 Mg C ha-1). Estimates of net ecosystem balance varied depending on the approach used, with high and sometimes unrealistic Rsh values tipping net ecosystem production into C source territory, but temporally smoothed estimates of long-term C increment indicating instead that all chronosequence stands were C sinks. We conclude that late successional and old growth forests should be prioritized for protection and management, as they provide comparable C sequestration and superior storage to earlier successional forests and support a wide variety of other critical ecosystem services.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

7-9-2021

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