Date of Award

2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Natural Resources

First Advisor

Anthony W. D'Amato

Abstract

Climate change is predicted to have variable and uncertain effects on forested ecosystems globally. In the northeastern US, natural disturbances have historically been a central driver of forest successional dynamics, but as climate warming is projected to alter the frequency and severity of these events, post-disturbance management strategies to sustain biodiversity and ecosystem services must adaptively change to promote forest resilience. A suite of adaptive silvicultural actions has been proposed to promote forest resilience in the face of uncertainty, but due to the multi-decadal scale of forest management, initial field experiments are only beginning to show results. To address these challenges, this dissertation combines field studies with landscape simulation modeling to examine forest composition and structure in the context of climate change and adaptive management. To accomplish this, we examine three agents of forest change and associated management responses to predict structural and compositional outcomes.

First, we examined short-term forest recovery following a tornado event in southern Massachusetts to understand how post-disturbance management interventions (i.e., salvage logging) impacted regenerating forest composition and function relative to stand-replacing wind. Results demonstrate that the compound disturbance of salvage logging may initially homogenize regeneration in the absence of structural legacies with potentially cascading impacts on future forest function. Next, we used landscape simulation models to examine the impacts of future climate change on forest composition and biomass in northern Vermont and New Hampshire over the next century to determine the potential for adaptive management to compensate for climate-induced declines for several key tree species. Results indicate that long-term successional trajectories play the largest role in driving species composition shifts and aboveground biomass, but higher application rates of adaptive silviculture offsets biomass declines and increases the presence of future-adapted species under moderate levels of warming. Finally, we modeled the impacts of ash (Fraxinus spp.) loss due to Emerald Ash Borer (EAB; Agrilus planipennis) invasion on forest composition and structure to understand future forest dynamics following the loss of this genus. Results demonstrate that while mature ash biomass loss does not impact successional trajectories at the landscape level, loss of ash at the local scale promotes increases in sugar maple biomass, suggesting that dominant hardwoods are likely to replace lost white ash biomass in the future.

Collectively, this work highlights the utility of adaptive silviculture in promoting forest resilience in the face of a warming climate, but underscores that implementing these strategies across a matrix of diverse land ownerships in northern New England and at rates required to affect change may pose challenges to the sustained adaptive management of forests in this region. Despite socioecological constraints, outcomes of this work can inform management planning to promote forest adaptability given projected changes in climate and provide a framework for employing adaptive silvicultural approaches to promote resilience in a changing world.

Language

en

Number of Pages

220 p.

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