Long-Term effects of Chronic Additions of Nitrogen, Sulfur and Lime on the Growth and Development of a Central Appalachian Forest

Abstract

The central Appalachian region has historically received some of the highest levels of nitrogen and sulfur deposition in the eastern United States. Base poor parent material coupled with future increases in more intensive forest management present a scenario of potential base cation depletion and decreased fertility of central Appalachian forest soils. The Fork Mountain Long Term-Soil Productivity (FM LTSP) site was established in 1996 at the Fernow Experimental Forest (FEF) to document the effects of increased nitrogen (N) and sulfur (S) deposition on a young aggrading forest. I utilized data recorded at multiple points in time in this long-term study to characterize the effects of chronic additions of nitrogen, sulfur, and dolomitic lime on the productivity of the overstory trees of the site. I also setup a framework and calibrated a commonly used forest growth model to project of the effects of the treatments on the trees over the next 40 years. v Table of Contents Abstract ………………………………………………………………………………………….ii Dedication ……………………………………………………………………………………….iii Acknowledgements……………………………………………………………………………...iv Table of Contents ………………………………………………………………………………..v List of Figures…………………………………………………………………………………..vii List of Tables …………………………………………………………………………………..viii Chapter 1. General Introduction ……………………………………………………………….1 Chapter 2. Effects of 21 years of increased nitrogen and sulfur on stand growth and species composition in an aggrading Appalachian hardwood forest. ………………………………...5

Long-Term Projection of Species-Specific Responses to Chronic Additions of Nitrogen, Sulfur, and Lime

“…The 40-year volume projections followed patterns that were mostly consistent with trends observed during the first 21 years of treatment [41]. Yellow-poplar, black cherry, red maple, and cucumbertree all showed stable, long-term positive responses to treatments.…”

“…A theoretical mortality function was included that would generally follow the dynamics described by [40]. In the LTSP study, pin cherry dominance had already begun to senesce based on severely declining relative importance values in 2012 and 2017 [41]. Pin cherry tree mortality was modified in the model by removing 50% of each tree record for each time step until the species was no longer present in the overstory.…”