Anthropogenic Actions Trigger the Rise and Fall of Black Cherry

Research Issue

[photo:] Two mature black cherry tree trunks in a forest.In the Allegheny Plateau region of the Eastern United States, the forests were once dominated by old-growth hemlock–beech–maple forests, but the structure and composition of these forests have changed dramatically over time. The early twentieth century saw cutting occurring in phases with the removal of white pine first (ship masts), followed by hemlock removal (tanning industry) and ultimately a complete overstory removal. The resulting conditions of clear-cutting, deer overabundance and rising nitrogen deposition favored greater dominance by the shade-intolerant, unpalatable, and nitrogen-demanding black cherry.

Black cherry subsequently increased in relative abundance at some sites compared to precolonial levels across the Northeast and became more dominant in its distribution on the Allegheny Plateau in Pennsylvania and New York. Regionally, black cherry is a keystone (or, foundational) species providing excellent wildlife habitat and serving as the backbone of a high value timber economy.

More recently, black cherry has not fared so well as evidenced by diminished establishment, growth, and survival. Sustaining the critical values and services provided by black cherry forests has become increasingly challenging and threatens to alter the ecology, economic and even cultural values associated with this iconic species within the heart of its range.

Our Research

Scientists aimed to determine the underlying causes of observed declines in black cherry by using a combination of synthesis of existing work and new analyses. They focused on five factors known or assumed to influence forest health broadly and black cherry dynamics specifically: climate variability, deer browsing, senescence, negative plant–soil microbe feedback loops (i.e., pathogens), and reduced nitrogen availability.

Among all the hypotheses explored, declining nitrogen and increase in pathogens are both consistent with and spatially and temporally coincident with the declines in black cherry over the past quarter century. Declines in nitrogen are associated with decreases in nitrogen deposition which have resulted from the 1990 Clean Air Act Amendments. These deposition reductions are particularly pronounced on the Allegheny Plateau because this region experienced among the highest nitrate deposition rates in the East. Increase in pathogens can occur as forests age and it is reasonable to hypothesize that the high relative abundance of black cherry in the Allegheny hardwood forests may cause higher densities of pathogenic fungi that limit black cherry establishment, growth, and survival.

Expected Outcomes

Given that black cherry responds strongly to fluctuating nitrogen dynamics and negative plant–soil feedback loops, it is possible that observed regional changes to black cherry may signal looming changes to population dynamics of other tree species and overall species composition across the eastern deciduous forests. The hypothesized roles of nutrient availability and pathogen dynamics deserves further investigation in black cherry and other species.

Research Results

Royo, Alejandro A; Vickers, Lance A; Long, Robert P; Ristau, Todd E; Stoleson, Scott H; Stout, Susan L. 2021. The Forest of Unintended Consequences: Anthropogenic Actions Trigger the Rise and Fall of Black Cherry. BioScience. 2021: biab002. 14 p.

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Principal Investigators

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  • Last modified: March 12, 2021