Chris E. Johnson

Syracuse University | SU · Department of Civil and Environmental Engineering

Acidic deposition has resulted in the loss of available soil calcium from base-poor soils in the northeastern United States. In 1999, wollastonite (CaSiO3) was experimentally added to a watershed at the Hubbard Brook Experimental Forest in New Hampshire in an attempt to restore the base saturation of the soil to its estimated pre-acidification leve...

Carbon (C) sequestration in forest biomass and soils may help decrease regional C footprints and mitigate future climate change. The efficacy of these practices must be verified by monitoring and by approved calculation methods (i.e., models) to be credible in C markets. Two widely used soil organic matter models - CENTURY and RothC - were used to...

The Catskills forest provides a valuable array of ecosystem services for local and regional populations, including the provision of forest products, wildlife habitats, and high-quality water. These services depend on chemical and biological processes that occur in forest soils. In 2011, we sampled soils in 25 headwater catchments in the Catskills r...

Chemical changes along headwater streams at the Hubbard Brook Experimental Forest in New Hampshire suggest that important differences exist in biogeochemical cycles along an altitudinal gradient within small watershed ecosystems. Using data collected during the period 1982–92, we have constructed element budgets [Ca, Mg, K, Na, Si, Al, dissolved or...

The biogeochemical model, PnET-BGC, was modified and parameterized using field data from an experimental whole-tree harvest of watershed (W5) in 1983–1984 at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA. The model simulated the hydrology, biomass accumulation, and soil solution and stream water chemistry responses to forest cutt...

Chemical weathering of minerals is the principal mechanism by which base cations (Ca ²⁺ , Mg ²⁺ , K ⁺ , and Na ⁺ ) are released and acidity is neutralized in soils, bedrock, and drainage waters. Quantifying the release of base cations from watershed soils is therefore crucial for the calculation of “critical loads” of atmospheric acidity to forest...

Data collected from research networks present opportunities to test theories and develop models about factors responsible for the long-term persistence and vulnerability of soil organic matter (SOM). Synthesizing datasets collected by different research networks presents opportunities to expand the ecological gradients and scientific breadth of inf...

Process ecosystem models are useful tools to provide insight on complex, dynamic ecological systems, and their response to disturbances. The biogeochemical model PnET-BGC was modified and tested using field observations from an experimentally whole-tree harvested northern hardwood watershed (W5) at the Hubbard Brook Experimental Forest (HBEF), New...

Data collected from research networks present opportunities to test theories and develop models about factors responsible for the long-term persistence and vulnerability of soil organic matter (SOM). Synthesizing datasets collected by different research networks presents opportunities to expand the ecological gradients and scientific breadth of inf...

Changes in soil carbon stocks following forest harvest can be an important component of ecosystem and landscape-scale C budgets in systems managed for bioenergy or carbon-trading markets. However, these changes are characterized less often and with less certainty than easier-to-measure aboveground stocks. We sampled soils prior to the whole-tree ha...

Sugar maple decline in eastern North America is caused by a complex combination of factors, with soil nutrition being one of several important determinants. Given the complexity of sugar maple population dynamics and the geographic extent of the species, we support Bailey et al.’s (2019, Can. J. For. Res. 49(7), doi:10.1139/cjfr-2018-0207) argument...

Prescribed fire is an important tool for rangeland management in sage-steppe ecosystems, yet the long-term effects of this practice on soil hydraulic properties are not well known. We explore interactions among site geomorphology, soil organic carbon (SOC) soil N, soil water repellency (SWR), and plant community type on infiltration properties befo...

Understanding the impacts of clear-cutting is critical to inform sustainable forest management associated with net primary productivity and nutrient availability over the long-term. Few studies have rigorously tested model simulations against field measurements which would provide more confidence in efforts to quantify logging impacts over the long...

Harvest residue retention or removal can influence soil carbon (C) sequestration during forest management. Many studies have explored the factors that affect the direction and extent of changes in soil C after different harvest residue management practices. However, the effect of soil properties, especially soil texture, on the difference in minera...

Forest harvesting can impact site quality by removing essential nutrients, exacerbating the effects of historic base cation losses associated with acid deposition. We studied the 30-year trajectory of forest recovery from clearcutting (whole-tree harvest (WTH)) in a forest originally dominated by sugar maple (Acer saccharum Marsh.). At both the wat...

Aluminum concentrations decreased on soil exchange sites and in soil solutions after a whole-watershed wollastonite (CaSiO3) treatment at the Hubbard Brook Experimental Forest in New Hampshire. This study was conducted to determine whether these decreases could be explained by changes in organically bound Al (Alorg) in soils. The concentrations of...

Recent soils research has shown that important chemical soil characteristics can change in less than a decade, often the result of broad environmental changes. Repeated sampling to monitor these changes in forest soils is a relatively new practice that is not well documented in the literature and has only recently been broadly embraced by the scien...

In terrestrial ecosystems, a large portion (20-80%) of the dissolved Si (DSi) in soil solution has passed through vegetation. While the importance of this ‘terrestrial Si filter’ is generally accepted, few data exist on the pools and fluxes of Si in forest vegetation and the rate of release of Si from decomposing plant tissues. We quantified the po...

Significance This research breaks new ground by showing that, contrary to generally accepted theories of ecosystem development, calcium depletion has been occurring for millennia as a natural consequence of long-term ecosystem development. This natural process predisposed forest ecosystems in the region to detrimental responses to acid rain in the...

We investigated the interactions among pH, Al solubility and Al–soil organic matter (SOM) complexation to test the hypothesis that competition between Al and H ions for cation binding sites on soil organic matter (SOM) determines soil pH and Al solubility in acidic forest soils in the northeastern U.S. Samples from five soil horizons in 39 forested...

Forest health deteriorated in eastern North America as a result of depletion of available soil base cations by elevated inputs of acid deposition. We experimentally restored available calcium (Ca) to soils of a forested watershed at Hubbard Brook, New Hampshire, and measured the response of fine root biomass 14 years after treatment. In this northe...

Long-term forest soil monitoring and research often requires a comparison of laboratory data generated at different times and in different laboratories. Quantifying the uncertainty associated with these analyses is necessary to assess temporal changes in soil properties. Forest soil chemical properties, and methods to measure these properties, ofte...

Study region: The Catskills region of New York State is largely forested and dominated hydrologically by stream watersheds with few natural lakes. The area experiences intensive water resources management and ecosystem monitoring due to its strategic role as the principal water supply for New York City. Study focus: We analyzed average daily flows...

Environmental context Calcium silicate was added to a forest watershed in New Hampshire, USA, to accelerate its recovery from acid rain. The acid-base status of soil and stream quality improved over the 12-year study, with the most pronounced response in the upper elevation and the upper soil of the watershed. A total of 95% of the added calcium an...

The decomposition of coarse woody debris contributes to forest nutrient sustainability and carbon (C) balances, yet few field studies have been undertaken to investigate these relationships in northern hardwood forests. We used a paired-sample approach to study the decomposition of sugar maple (Acer saccharum Marsh.), American beech (Fagus grandifo...

Terrestrial soil is a large reservoir of atmospherically deposited mercury (Hg). However, few studies have evaluated the accumulation of Hg in terrestrial ecosystems in the northeastern United States, a region which is sensitive to atmospheric Hg deposition. In this study, we characterize Hg and organic matter in soil profiles from 139 sampling sit...

Calcium amendment is a restorative option for nutrient-depleted, acidic soils in the forests of the northeastern United States. We studied the effects of watershed-scale wollastonite (CaSiO3) application on the structural composition of soil organic matter (SOM) and hot-water-extractable organic matter (HWEOM) at the Hubbard Brook Experiment Forest...

Calcium amendment can help improve forest sustainability in stands that have been impacted by chronic acid deposition. An important component of this improvement is the stimulation of the microbial activity that supports ecosystem nutrient cycling processes. To test the hypothesis that Ca treatment alters the structure and solubility of organic mat...

Forest decline in the northeastern United States has been linked to the effects of acid deposition on soil nutrients. To test this link, we added a calcium silicate mineral to a paired watershed at the Hubbard Brook Experimental Forest, New Hampshire, in an amount designed to gradually replace the estimated amount of calcium lost as a result of hum...

Purpose Residue retention is important for nutrient and water economy in subtropical plantation forests. We examined decomposing hoop pine (Araucaria cunninghamii Ait. Ex D. Don) residues—foliage, branches, and stem wood—to determine the changes in structural chemistry that occur during decomposition. Materials and methods Residues were incubated...

Purpose Microbial decomposition of soil organic matter (SOM) is generally believed to be heterogeneous, resulting in the preferential loss of labile compounds such as carbohydrates and proteins and the accumulation of recalcitrant compounds such as lipids and lignin. However, these fractions are difficult to measure directly in soils. We examined p...

Evaluations of the local effects of global change are often confounded by the interactions of natural and anthropogenic factors that overshadow the effects of climate changes on ecosystems. Long-term watershed and natural elevation gradient studies at the Hubbard Brook Experimental Forest and in the surrounding region show surprising results demons...

Many important questions in ecosystem science require estimates of stocks of soil C and nutrients. Quantitative soil pits provide direct measurements of total soil mass and elemental content in depth-based samples representative of large volumes, bypassing potential errors associated with independently measuring soil bulk density, rock volume, and...

Watershed 1 (W1) at the Hubbard Brook Experimental Forest in New Hampshire, with chronically low pH and acid neutralizing capacity (ANC) in surface water, was experimentally treated with calcium silicate (CaSiO3; wollastonite) in October 1999 to assess the role of calcium (Ca) supply in the structure and function of base-poor forest ecosystems. Wol...

Iron (Fe) is ubiquitous in forest ecosystems and its cycle is thought to influence the development of soil, particularly Spodosols (podsolization), and the biogeochemistry of macronutrients such as carbon (C), nitrogen (N), and phosphorus (P), as well as many trace metals. The cycle of Fe in northern hardwood forests remains poorly understood. To a...

La coupe a blanc des forets feuillues nordiques interrompt le recyclagle des nutriments et augmente souvent l'exportation de nutriments mineraux (Ca, Mg, K) dans les eaux de drainage. Quand ces pertes par lessivage sont ajoutees aux exportations de nutriments dans le bois recolte, le total peut representer une fraction significative des stocks sur...

Liming has been used to mitigate effects of acidic deposition in forest ecosystems. This study was designed to examine the effects of calcium (Ca) supply on the spatial patterns and the relations between soil and soil solution chemistry in a base-poor forest watershed. Watershed 1 at the Hubbard Brook Experimental Forest in New Hampshire, USA was e...

Aluminum (Al) chemistry was studied in soils and waters of two catchments covered by spruce (Picea abies) monocultures in the Czech Republic that represent geochemical end-members of terrestrial and aquatic sensitivity to acidic deposition. The acid-sensitive Lysina catchment, underlain by granite, was compared to the acid-resistant Pluhův Bor catc...

Hot-water-extractable organic matter (HWEOM) has been shown to be highly correlated with microbial biomass in forest soils. We conducted elemental and 13C solid-state nuclear magnetic resonance spectroscopic analyses to assess the composition and structural chemistry of HWEOM and its variations with soil depth within O horizons in a forest site in...

We conducted a resurvey of the O horizon in 2001 in watersheds previously sampled in 1984 under the Direct/Delayed Response Program (DDRP) to evaluate the effects of reductions in acidic deposition in the northeastern United States. In this 17-yr interval, median base saturation in the Oa horizon decreased from 56.2% in 1984 to 33.0% in 2001. Effec...

We surveyed 113 lakes in the northeastern U.S. in 2001 that had previously been sampled in 1986 to evaluate the effects of reductions in acidic deposition on the concentrations and speciation of aluminum (Al). We found ubiquitous decreases in the concentrations of total Al and inorganic monomeric aluminum (Ali) across the region. Median total Al de...

In terrestrial ecosystems, the largest pool of amorphous silica (ASi) is stored in soils and is an important reservoir of biologically active Si for the global biogeochemical cycling of Si. Only limited data are available that quantify the size of this reservoir and often these estimates are made from the physical separation of silt-sized phytolith...

Globally significant increases in the riverine delivery of nutrients and suspended particulate matter have occurred with deforestation. We report here significant increases in streamwater transport of dissolved silicate (DSi) following experimental forest harvesting at the Hubbard Brook Experimental Forest, NH, USA. The magnitude of the streamwater...

The southwestern Adirondack region of New York receives among the highest rates of atmospheric nitrogen (N) deposition in the USA. Atmospheric N deposition to sensitive ecosystems, like the Adirondacks, may increase the acidification of soils through losses of exchangeable nutrient cations, and the acidification of surface waters associated with en...

We quantified the dynamics of the tree stratum at Hubbard Brook Experimental Forest (HBEF), New Hampshire, to examine why live biomass reached a plateau in about 1980. Total aboveground biomass increased from 209Mgha¹ in 1981 to 216 Mgha¹ in 2001. From 1991 to 2001, in-growth of10cm diameter at breast height (DBH) trees averaged 4.7 treesha¹year ¹...

Soil organic matter (SOM) plays an important role in governing soil properties and nutrient cycling in forest ecosystems. Clear-cutting alters the SOM cycle by changing decomposition rates and organic matter (OM) inputs to the forest ecosystem. We studied the 15-year clear-cutting response on the properties and composition of SOM at the Hubbard Bro...

Changes in lake water chemistry between 1984 and 2001 at 130 stratified random sites across the northeastern United States were studied to evaluate the population-level effects of decreases in acidic deposition. Surface-water S04(2-) concentrations decreased across the region at a median rate of -1.53 microequiv L(-1) year(-1). Calcium concentratio...

The biogeochemical behavior of carbon in the forested watersheds of the Hubbard Brook Experimental Forest (HBEF) was analyzed in long-term studies. The largest pools of C in the reference watershed (W6) reside in mineral soil organic matter (43% of total ecosystem C) and living biomass (40.5%), with the remainder in surface detritus (14.5%). Repeat...

Nuclear magnetic resonance (NMR) spectroscopy is a useful tool for examining the structural chemistry of natural organic matter. The use of cross-polarization and magic-angle spinning to study 13C functionality (CPMAS 13C NMR) is convenient, but not always quantitative. We used various 13C NMR techniques to examine the structural chemistry of bark...

Concentrations of both aluminium (Al) and dissolved organic carbon (DOC) in stream waters are likely to be regulated by factors that influence water flowpaths and residence times, and by the nature of the soil horizons through which waters flow. In order to investigate landscape-scale spatial patterns in streamwater Al and DOC, we sampled seven str...

Global positioning system (GPS) technology is rapidly replacing tape, compass, and traditional surveying instruments as the preferred tool for estimating the positions of environmental research sites. One important problem, however, is that it can be difficult to estimate the uncertainty of GPS-derived positions. Sources of error include various sa...

With more and more stringent regulatory requirements being imposed on the drinking water industry, it is increasingly important to ensure that standards are being met. This means that water treatment plants and their managers rely heavily on measurement equipment to ensure that quality standards are being met. With regard to particle removal, it ha...

The spatial variability of long-term chemical weathering in a small watershed was examined to determine the effect of landscape position and vegetation. We sampled soils from forty-five soil pits within an 11.8-hectare watershed at the Hubbard Brook Experimental Forest, New Hampshire. The soil parent material is a relatively homogeneous glacial til...

The use of alkyl-Pb additives in gasoline during the 20th century resulted in widespread Pb pollution. The objective of this study was to determine the relative importance of atmospherically deposited Pb and Pb released through weathering to soil Pb pools at the Hubbard Brook Experimental Forest, New Hampshire. We employed a selective extraction me...

In acid-sensitive watersheds of the northeastern US, decreases in SO2 emissions and atmospheric deposition of sulfur have not been accompanied by marked changes in pH and acid neutralizing capacity (ANC). To better understand this phenomenon, we investigated the long-term trends in soil solution (1984–1998) and stream water (1982–2000) chemistry al...

Mobility of organic matter (OM) in soils is restricted by sorption to mineral surfaces. We investigated the sorption of hydrophilic and Hydrophobic OM fractions on mineral soils of the Hubbard Brook Experimental Forest (HBEF), New Hampshire. Organic matter was extracted with 0.1 M NaOH from O- and Bh-horizons, fractionated into hydrophilic and hydr...

Irrigation with saline water is increasingly practised yet an understanding of plant response to different salt types remains largely elusive. Our study investigated the effects of irrigation with simulated effluent containing three salts on the growth and composition of a common South African pasture grass. We treated pots of kikuyu (Pennisetum cl...

Over the past 50 years,acid deposition in the northeastern USA has leached calcium and other base cations (K, Na, and Mg) from the soil exchange complex, creating a nutrient-poor environment for trees. In order to quantify losses from the soil exchange pool and estimate ecosystem recovery from acid deposition, inputs from atmospheric deposition and...

Soil organic matter plays an important role in soil properties and influences ecosystem cycles of C, N, Al, Fe, and other major and trace elements. We examined spatial variations in the structure and chemistry of soil organic matter at the Hubbard Brook Experimental Forest in New Hampshire, USA. Humic substances were extracted and isolated chromato...

Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/62683/1/423824a.pdf

The depletion of calcium in forest ecosystems of the northeastern USA is thought to be a consequence of acidic deposition and to be at present restricting the recovery of forest and aquatic systems now that acidic deposition itself is declining. This depletion of calcium has been inferred from studies showing that sources of calcium in forest ecosy...

Negative correlations between soil pH and cation exchange capacity (CEC) or base saturation in soils of the northeastern USA and Scandinavia have raised questions regarding the nature of cation exchange in acid forest soils. Using data from three small-catchment studies and an extensive regional survey of soils in the northeastern USA, I examined r...

Forest harvesting alters the organic matter cycle by changing litter inputs and the decomposition regime. We hypothesized that these changes would result in differences in organic matter chemistry between clear-cut and uncut watershed ecosystems. We studied the chemistry of soil organic matter (SOM), and dissolved organic carbon (DOC) in soil solut...

In northern regions, spring snowmelt generally results in an episodic decline of surface water pH. Natural organic acids may be an important factor in this type of pH change. We studied the variations in the acid/base character of aquatic organic acids during spring snowmelt in 1997 at Svartberget, a stream rich in total organic carbon (TOC) that i...

Forest soil Ca depletion through leaching and vegetation uptake may threaten long-term sustainability of forest productivity in the southeastern USA. This study was conducted to assess Ca pools and fluxes in a representative southern Piedmont forest to determine the soil Ca depletion rate. Soil Ca storage, Ca inputs in atmospheric deposition, and o...

ABSTRACT,behavior of forest soils (Krug and Frink, 1983; Driscoll et al., 1988; Johnson and Lindberg, 1992; Likens et al., Knowledge of soil chemistry is useful in assessing the sensitivity 1996). In the northeastern USA, acid-sensitive water- of forested areas to natural and anthropogenic disturbances, but char- sheds,are common,in glaciated regio...

The presence of magnetic species, Fe in particular, decreases the effectiveness of nuclear magnetic resonance (NMR) analysis of soil organic matter (SOM), especially in Spodosols. This study was conducted to evaluate the utility of dithionite, stannous chloride, and hydrofluoric acid (HF) extraction for Fe removal and solid-state 13C NMR spectral e...

Temporal changes in major solute concentrations in six Czech Republic lakes were monitored during the period 1984–1995. Four chronically-acidic lakes had decreasing concentrations of strong-acid anions (CSA = SO4 2- + NO3 - + Cl-), at rates of 3.0 to 9.0 eq L-1 yr-1. Decreases in SO4 2-, NO3 -, and Cl- (at rates up to 5.1 eq L-1 yr-1, 3.2 eq L-1 yr...

A synthesis of the biogeochemistry of Ca was done during 1963–1992in reference and human-manipulated forest ecosystems of the Hubbard BrookExperimental Forest (HBEF), NH. Results showed that there has been a markeddecline in concentration and input of Ca in bulk precipitation, an overalldecline in concentration and output of Ca in stream water, and...

Weathering of minerals in soils provides important plant nutrients and consumes acidity, yet mineral weathering is difficult to observe and quantify. We derived present-day weathering flux estimates for soil minerals in a forested watershed in central New Hampshire using a geochemical mass balance. The Cone Pond watershed is characterized by low-al...