Temporal changes in forest structure, composition, and carbon storage at Trelease Woods

Old-growth forests in the eastern United States are experiencing widespread structural and compositional shifts driven by the combined effects of biotic invasions, herbivory, and mesophication – characterized by the rise in shade-tolerant species due to fire suppression. Understanding how these drivers influence forest resilience is crucial for predicting long-term ecosystem dynamics. In this thesis, I analyzed historical datasets spanning up to 96 years to examine changes in species composition, structure, and carbon (C) storage in Trelease Woods, a temperate old-growth forest remnant in central Illinois. My findings revealed significant declines in species richness and diversity, particularly in the sapling layer, with increasing dominance of sugar maple (Acer saccharum) and Ohio buckeye (Aesculus glabra) across all size classes. These trends suggest increasing species homogenization driven by pest and pathogen outbreaks, rising deer populations, and fire suppression. Despite substantial losses in ash (Fraxinus spp.) and elm (Ulmus spp.) populations due to the introduction of the emerald ash borer and Dutch elm disease, aboveground biomass and basal area have remained stable over the past 80 years, indicating compensatory dynamics through the increased growth of non-host species. Additionally, small declines in soil C and a modest deadwood pool suggest that increased mortality has not yet substantially altered C storage. These findings reveal the resilience of old-growth forests in maintaining structural and functional stability following biotic disturbances while highlighting how these same processes weaken the species diversity and lead to the homogenization of the landscape. This study emphasizes the value of long-term ecological monitoring for informing forest management strategies in an era of rapid environmental change.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Natural Resources & Environmental Sciences

Grantor

University of Illinois Urbana-Champaign

Year dc:date

2025

Author dc:creator

• Alvarez, Jennifer

Contributors dc:contributor

• Fraterrigo, Jennifer M.
• Dalling, James W.
• Yannarell, Anthony

• Old-growth
• Forest Dynamics
• Species Composition
• Carbon Storage
• Longitudinal Study
• Carbon Budget
• Deadwood
• Coarse Woody Debris
• Soil Carbon
• Aboveground Biomass
• Biodiversity

Statement dc:rights

• Copyright 2025 Jennifer Alvarez

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/129333

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F129333