Defense Date

2017

Document Type

Thesis

Degree Name

Master of Science

Department

Biology

First Advisor

Dr. Chris Gough

Second Advisor

Dr. Julie Zinnert

Third Advisor

Dr. Paul Bukaveckas

Fourth Advisor

Dr. Derek Johnson

Abstract

Moderate severity disturbances, which only kill a subset of canopy trees (e.g., via insects, pathogens, and windthrow), are increasingly widespread, and can alter forest structure and production. Whether moderate severity disturbance similarly affects the net primary production (NPP) of different forest stands within inherently heterogeneous landscapes, however, is unknown. We experimentally disturbed three, 2-ha stands varying in forest structure and primary production, reducing stand basal area 38 to 66 % by stem girdling all mature early successional aspen (Populus) and birch (Betula). For nearly a decade, we examined how the forest stands restructured and recovered, and linked post-recovery physical and biological structure with light absorption and wood NPP. Disturbance significantly altered the structure of all stands and prompted a similar decade-long pattern of primary production decline and recovery. All stands exhibited an initial reduction in wood NPP, recovering to, or exceeded pre-disturbance levels within eight years. Following the recovery of wood NPP, more biologically diverse forest canopies with higher leaf area indexes captured more light, and, subsequently, had higher rates of wood NPP. We provide limited support that disturbance may enhance long-term primary production through its effects on canopy structural reorganization. We conclude that, while the forests examined responded similarly to disturbance, improved understanding of different forest ecosystems’ response to disturbance remains critical to informing carbon management decisions across diverse landscape mosaics.

Rights

© Benjamin Tai Sagara

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

7-11-2017

Available for download on Wednesday, July 11, 2018

Included in

Biology Commons

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