Acidic Deposition and Climate Warming as Drivers of Tree Growth in High-Elevation Spruce-Fir Forests of the Northeastern US

Wason, Jay W.; Beier, Colin M.; Battles, John J.; Dovčiak, Martin

doi:10.3389/ffgc.2019.00063

Cited by 14 publications

(4 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Acid impacted biota such as red spruce (Picea rubens Sarg.) [14,15] and brook trout (Salvelinus fontinalis) [16] have shown signs of recovery. Additionally, SOM concentrations and forest floor thickness have decreased [13], while dissolved organic carbon (DOC) concentrations in soil and surface waters across northeastern U.S. and Europe have increased [12,17].…”

Section: Introductionmentioning

confidence: 99%

Landscape Influence on the Browning of a Lake Watershed in the Adirondack Region of New York, USA

LoRusso

McHale

et al. 2020

Soil Systems

View full text Add to dashboard Cite

Watershed recovery from long-term acidification in the northeastern U.S. has been characterized by an increase in the influx of dissolved organic matter (DOM) into surface waters. Increases in carbon quantity and shifts to more aromatic and “colored” OM has impacted downstream lakes by altering thermal stratification, nutrient cycling and food web dynamics. Here, we used fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC) to model predominant carbon quality fractions and their seasonal changes within surface waters along landscape positions of Arbutus Lake watershed in the Adirondack region of NY, USA. All DOM components were terrestrial in origin, however their relative fractions varied throughout the watershed. DOM in headwater streams contained high fractions of recalcitrant (~43%) and microbial reprocessed humic-like OM (~33%), sourced from upland forest soils. Wetlands above the lake inlet contributed higher fractions of high molecular weight, plant-like organic matter (~30%), increasing dissolved organic carbon (DOC) concentrations observed at the lake inlet (492.5 mg L−1). At the lake outlet, these terrestrial fractions decreased significantly during summer months leading to a subsequent increase in reprocessed OM likely through increased microbial metabolism and photolysis. Comparisons of specific ultraviolet absorbance between this study and previous studies at Arbutus Lake show that OM draining upland streams (3.1 L·mg C−1 m−1) and wetland (4.1 L·mg C−1 m−1) is now more aromatic and thus more highly colored than conditions a decade ago. These findings provide insight into the emerging role that watersheds recovering from acidification play on downstream water quality.

show abstract

Section: Introductionmentioning

confidence: 99%

Landscape Influence on the Browning of a Lake Watershed in the Adirondack Region of New York, USA

LoRusso

McHale

et al. 2020

Soil Systems

View full text Add to dashboard Cite

show abstract

“…Our results, showing that iWUE plateaued and stomata responded strongly to increasing moisture availability and net Ca 2+ leaching from soil since 1975, provided support for observations of increasing ET in northern watersheds. As numerous studies have detected negative effects of acid deposition on NENA tree species (DeHayes et al ., 1999; Schaberg et al ., 2001; Halman et al ., 2011, 2013; Thomas et al ., 2013; Battles et al ., 2014; Engel et al ., 2016; Mathias & Thomas, 2018; Wason et al ., 2019), more thorough investigations of leaf gas exchange response are needed across species and community types before conclusions are drawn. While peak pollution loading has abated since 1990, legacy effects of long‐term net soil base cation depletion will delay soil recovery into the 21 st century (Lawrence et al ., 2012).…”

Section: Discussionmentioning

confidence: 99%

North American temperate conifer (Tsuga canadensis) reveals a complex physiological response to climatic and anthropogenic stressors

et al. 2020

View full text Add to dashboard Cite

Rising atmospheric CO 2 (c a) is expected to promote tree growth and lower water loss via changes in leaf gas exchange. However, uncertainties remain if gas-exchange regulation strategies are homeostatic or dynamical in response to increasing c a , as well as evolving climate and pollution inputs. Using a suite of tree ring-based δ 13 C-derived physiological parameters (Δ 13 C, c i , iWUE) and tree growth from a mesic, low elevation stand of canopy-dominant Tsuga canadensis in northeastern USA, we investigated the influence of rising c a , climate and pollution on, and characterised the dynamical regulation strategy of, leaf gas exchange at multidecadal scales. Isotopic and growth time series revealed an evolving physiological response in which the species shifted its leaf gas-exchange strategy dynamically (constant c i ; constant c i /c a ; constant c a − c i) in response to rising c a , moisture availability and site conditions over 111 yr. Tree iWUE plateaued after 1975, driven by greater moisture availability and a changing soil biogeochemistry that may have impaired a stomatal response. Results suggested that trees may exhibit more complex physiological responses to the changing environmental conditions over multidecadal periods, and complicating the parameterisation of Earth system models and the estimation of future carbon sink capacity and water balance in midlatitude forests and elsewhere.

show abstract

“…An example of a reversible regime shift associated with declining resilience is the switch from a mesotrophic to eutrophic lake with phosphorous loading [6], while an irreversible regime shift is the salinization of surface soils due to intensive agricultural management in semi-arid areas [7]. In forests, reversible transitions include the widespread decline of red spruce (Picea rubens) in the eastern US during the mid-20th century, which changed course and began recovery in the early 2000s following reductions in acid deposition coupled with warming temperatures [8][9][10]. An irreversible transition is the change from canopyto shrub-dominated ecosystems, as in the case of rhododendron (Rhododendron maximum) expansion in southern Appalachian riparian forests following the loss of American chestnut (Castanea dentata) to a fungal pathogen and the decline of eastern hemlock (Tsuga canadensis) due to an invasive insect pest [11].…”

Section: Introductionmentioning

confidence: 99%

Early warning signals of changing resilience in the biogeochemistry and biology of a northern hardwood forest

Contosta,

Battles,

Campbell

et al. 2023

Environ. Res. Lett.

View full text Add to dashboard Cite

Resilience is the ability of ecosystems to maintain function while experiencing perturbation. Globally, forests are experiencing disturbances of unprecedented quantity, type, and magnitude that may diminish resilience. Early warning signals are statistical properties of data whose increase over time may provide insights into decreasing resilience, but there have been few applications to forests. We quantified four early warning signals (standard deviation, lag-1 autocorrelation, skewness, and kurtosis) across detrended time series of multiple ecosystem state variables at the Hubbard Brook Experimental Forest, New Hampshire, USA and analyzed how these signals have changed over time. Variables were collected over periods from 25 to 55 years from both experimentally manipulated and reference areas and were aggregated to annual timesteps for analysis. Long-term (> 50 year) increases in early warning signals of stream calcium, a key biogeochemical variable at the site, illustrated declining resilience after decades of acid deposition, but only in watersheds that had previously been harvested. Trends in early warning signals of stream nitrate, a critical nutrient and water pollutant, likewise exhibited symptoms of declining resilience but in all watersheds. Temporal trends in early warning signals of some of groups of trees, insects, and birds also indicated changing resilience, but this pattern differed among, and even within, groups. Overall, ~60% of early warning signals analyzed indicated decreasing resilience. Most of these signals occurred in skewness and kurtosis, suggesting “flickering” behavior that aligns with emerging evidence of the forest transitioning into an oligotrophic condition. The other ~40% of early warning signals indicated increasing or unchanging resilience. Interpretation of early warning signals in the context of system specific knowledge is therefore essential. They can be useful indicators for some key ecosystem variables; however, uncertainties in other variables highlight the need for further development of these tools in well-studied, long-term research sites.

show abstract

Acidic Deposition and Climate Warming as Drivers of Tree Growth in High-Elevation Spruce-Fir Forests of the Northeastern US

Cited by 14 publications

References 44 publications

Landscape Influence on the Browning of a Lake Watershed in the Adirondack Region of New York, USA

Landscape Influence on the Browning of a Lake Watershed in the Adirondack Region of New York, USA

North American temperate conifer (Tsuga canadensis) reveals a complex physiological response to climatic and anthropogenic stressors

Early warning signals of changing resilience in the biogeochemistry and biology of a northern hardwood forest

Contact Info

Product

Resources

About