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173
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January 2001 - present
Publications
Publications (173)
In northern hardwood forests, litter decomposition might be affected by nutrient availability, species composition, stand age, or access by decomposers. We investigated these factors at the Bartlett Experimental Forest in New Hampshire. Leaf litter of early and late successional species was collected from four stands that had full factorial nitroge...
Soil respiration is the largest single efflux in the global carbon cycle and varies in complex ways with climate, vegetation, and soils. The suppressive effect of nitrogen (N) addition on soil respiration is well documented, but the extent to which it may be moderated by stand age or the availability of soil phosphorus (P) is not well understood. W...
Background
Reducing Emissions from Deforestation and forest Degradation (REDD+) is a program established under the United Nations Framework Convention on Climate Change (UNFCCC) to reduce carbon emissions from forests in developing countries. REDD+ uses an incentive-based approach whereby participating countries are paid to reduce forest carbon los...
Quantifying uncertainty is important to establishing the significance of comparisons, to making predictions with known confidence, and to identifying priorities for investment. However, uncertainty can be difficult to quantify correctly. While sampling error is commonly reported based on replicate measurements, the uncertainty in regression models...
Stomatal density, stomatal length, and carbon isotope composition can all provide insights into environmental controls on photosynthesis and transpiration. Stomatal measurements can be time-consuming; it is therefore wise to consider efficient sampling schemes. Knowing the variance partitioning at different measurement levels (i.e., among stands, p...
This code demonstrates three ways of propagating the uncertainty of total foliar Ca of forested stands that contain different numbers of individual trees. This code can recreate the analyses of Yanai et al. (2023) in Ecosystems, entitled: Propagating uncertainty in predicting individuals and means illustrated with foliar chemistry and forest biomas...
Successional, second-growth forests dominate much of eastern North America; thus, patterns of biomass accumulation in standing trees and downed wood are of great interest for forest management and carbon accounting. The timing and magnitude of biomass accumulation in later stages of forest development are not fully understood. We applied a “chronos...
Functional balance theory predicts that plants will allocate less carbon belowground when the availability of nutrients is elevated. We tested this prediction in two successional northern hardwood forest stands by quantifying fine root biomass and growth after 5–7 years of treatment in a nitrogen (N) x phosphorus (P) factorial addition experiment....
Stream fluxes are commonly reported without a complete accounting for uncertainty in the estimates, which makes it difficult to evaluate the significance of findings or to identify where to direct efforts to improve monitoring programs. At the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire, USA, stream flow has been monit...
Few previous studies have described patterns of leaf characteristics in response to nutrient availability and depth in the crown. Sugar maple has been studied for both sensitivity to light, as a shade-tolerant species, and sensitivity to soil nutrient availability, as a species in decline due to acid rain. To explore leaf characteristics from the t...
Quantifying uncertainty in forest assessments is challenging because of the number of sources of error and the many possible approaches to quantify and propagate them. The uncertainty in allometric equations has sometimes been represented by propagating uncertainty only in the prediction of individuals, but at large scales with large numbers of tre...
Nitrogen and phosphorus, alone or in combination, are the nutrients most often limiting to plants. Resorption is one way plants conserve nutrients, thereby reducing dependence on nutrient uptake from soil. We investigated foliar nutrient concentrations, ratios, and resorption in three northern hardwood species growing in eight stands across three s...
The influence of nutrient availability on transpiration is not well understood, in spite of the importance of transpiration to forest water budgets. Soil nutrients have the potential to affect tree water use through indirect effects on leaf area or stomatal conductance. For example, following addition of calcium silicate to a watershed at Hubbard B...
Statistical confidence in estimates of timber volume, carbon storage, and other forest attributes depends, in part, on the uncertainty in field measurements. Surprisingly, measurement uncertainty is rarely reported, even though national forest inventories routinely repeat field measurements for quality assurance. We compared measurements made by fi...
We use the Multiple Element Limitation (MEL) model to examine responses of 12 ecosystems to elevated carbon dioxide (CO2), warming, and 20% decreases or increases in precipitation. Ecosystems respond synergistically to elevated CO2, warming, and decreased precipitation combined because higher water‐use efficiency with elevated CO2 and higher fertil...
Foliar chemistry can be useful for diagnosing soil nutrient availability and plant nutrient limitation. In northern hardwood forests, foliar responses to nitrogen (N) addition have been more often studied than phosphorus (P) addition, and the interactive effects of N and P addition have rarely been described. In the White Mountains of central New H...
Ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) fungi are often studied independently, and thus little is known regarding differences in vertical distribution of these two groups in forests where they co-occur. We sampled roots at two soil depths in two northern hardwood stands in Bartlett, New Hampshire, co-dominated by tree species that asso...
Resource allocation theory posits that increased soil nutrient availability results in decreased plant investment in nutrient acquisition. We evaluated this theory by quantifying fine root biomass and growth in a long term, nitrogen (N) × phosphorus (P) fertilization study in three mature northern hardwood forest stands where aboveground growth inc...
Transparency in reporting is essential to scientific progress. No report should be considered complete without a full account of uncertainties, including those due to natural variation and measurement and model error and those incurred by handling problematic data, such as outliers. We randomly selected 132 papers published in 2019 from a list of 1...
Mercury (Hg), a neurotoxic pollutant, can be transported long distances through the atmosphere and deposited in remote areas, threatening aquatic wildlife through methylation and bioaccumulation. Over the last two decades, air quality management has resulted in decreases in Hg emissions from waste incinerators and coal-fired power plants across Nor...
The common loon (Gavia immer), a top predator in the freshwater food web, has been recognized as an important bioindicator of aquatic mercury (Hg) pollution. Because capturing loons can be difficult, statistical approaches are needed to evaluate the efficiency of Hg monitoring. Using data from 1998 to 2016 collected in New York’s Adirondack Park, w...
Reductions in atmospheric concentrations of greenhouse gases are urgently needed to avoid the most catastrophic consequences of warming. Reducing deforestation and forest degradation presents a climate change mitigation opportunity critical to meeting Paris Agreement goals. One strategy for decreasing carbon emissions from forests is to provide dev...
Long-term streamflow datasets inevitably include gaps, which must be filled to allow estimates of runoff and ultimately catchment water budgets. Uncertainty introduced by filling gaps in discharge records is rarely, if ever, reported. We characterized the uncertainty due to streamflow gaps in a reference watershed at the Hubbard Brook Experimental...
Mercury (Hg) in the environment has been receiving considerable attention in recent years, but little is known about Hg accumulation in trees. We analyzed Hg in tree rings from four tree species at the Hubbard Brook Experimental Forest in New Hampshire to determine whether Hg concentrations are more influenced by soil Hg concentrations, which have...
Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research sp...
Soils are the largest terrestrial pool of mercury (Hg), a neurotoxic pollutant. Pathways of Hg accumulation and loss in forest soils include throughfall, litterfall, soil gas fluxes, and leaching in soil solution, all of which will likely be altered under changing climate. We took advantage of three ongoing climate-change manipulation experiments a...
Leaf litterfall nutrient concentrations and their ratios are a common indicator of site nutrient status and a critical component of many ecosystem calculations. Concentrations of nitrogen (N) and phosphorus (P) in leaf litter are related to foliar concentrations, but they are reduced by nutrient resorption during senescence. Although nutrient resor...
Core Ideas
Detecting change depends on soil variability, sampling effort and desired confidence.
We illustrate detectable rates of change using data from the Calhoun Long‐Term Soil‐Ecosystem experiment.
The sampling intensity needed to detect change varied with soil depth and chemical element.
Experience at this LTSE can be used to improve long‐ter...
Resorption, the process of withdrawing foliar nutrients prior to leaf abscission, is one of the most important nutrient conservation mechanisms in trees. Along with foliar nutrient concentrations, foliar resorption can be used to infer nutrient limitation. We collected green and senesced leaves of five species in early successional stands in the Wh...
Downed coarse woody debris, also known as coarse woody detritus or downed dead wood, is challenging to estimate for many reasons, including irregular shapes, multiple stages of decay, and the difficulty of identifying species. In addition, some properties are commonly not measured, such as wood density and carbon concentration. As a result, there h...
Ecosystem budgets of water and elements can be difficult to estimate and are often unreplicated, making it challenging to provide confidence in estimates of ecosystem pools and fluxes. We conducted a survey to learn about current practices in reporting uncertainties in precipitation, streamflow, soils, and vegetation. Uncertainty derives from natur...
The design of a precipitation monitoring network must balance the demand for accurate estimates with the resources needed to build and maintain the network. If there are changes in the objectives of the monitoring or the availability of resources, network designs should be adjusted. At the Hubbard Brook Experimental Forest in New Hampshire, USA, pr...
Biplot of principal components 2 and 3 with the vector for each precipitation gauge.
(PDF)
Distribution of mean absolute error for all gauge-reduction scenarios, grouped by the number of remaining gauges on the south-facing slope.
This is the same as Fig 5A, except it uses Thiessen polygon interpolation.
(PDF)
Principal component analysis.
(PDF)
The distribution of differences between scenarios using IDW (Fig 5A) and Thiessen polygons (S1 Fig) for the south facing slope.
(PDF)
Biplot of principal components 1 and 2 with the vector for each precipitation gauge.
(PDF)
Mercury (Hg) is deposited from the atmosphere to remote areas such as forests, but the amount of Hg in trees is not well known. To determine the importance of Hg in trees, we analyzed foliage, bark and bole wood of eight tree species at four sites in the northeastern USA (Huntington Forest, NY; Sleepers River, VT; Hubbard Brook, NH; Bear Brook, ME)...
Concentrations of Hg in each composited tissue sample in this study.
(DOCX)
Forest productivity on glacially derived soils with weatherable phosphorus (P) is expected to be limited by nitrogen (N), according to theories of long-term ecosystem development. However, recent studies and model simulations based on resource optimization theory indicate that productivity can be co-limited by N and P. We conducted a full factorial...
Designs for litterfall sampling can be improved by understanding the sources of uncertainty in lit-terfall mass and nutrient concentration. We compared the coefficient of variation of leaf litterfall mass and nutrient concentrations (nitrogen, phosphorus, calcium, magnesium, and potassium) at different spatial scales and across years for six northe...
Roots are important to ecosystem nutrient pools and fluxes, but they are difficult to sample for tissue analysis, especially at depth. We analyzed patterns of nutrient concentrations in live roots up to 20 mm in diameter collected from quantitative soil pits in six northern hardwood sites at the Bartlett Experimental Forest, New Hampshire, USA. Roo...
Quantifying root biomass in rocky forest soils is challenging. This report provides practical advice for field sampling and laboratory processing of root biomass in these settings. Manual coring is the most efficient method for sampling fine root biomass in the upper soil profile (we sampled to 30 cm). However, careful correction for coarse fragmen...
Mercury (Hg) in tree wood has been overlooked, in part because concentrations are so low as to be below detection limits of some analytical methods, but it is potentially important to forest ecosystem processes and budgets. We tested methods for the preparation and determination of Hg in tree wood by analysing samples of four tree species at the Hu...
Abstract Estimating streamwater solute loads is a central objective of many water‐quality monitoring and research studies, as loads are used to compare with atmospheric inputs, to infer biogeochemical processes, and to assess whether water quality is improving or degrading. In this study, we evaluate loads and associated errors to determine the bes...
Monitoring solutes in precipitation inputs and stream water exports at small watersheds has greatly advanced our understanding of biogeochemical cycling. Surprisingly, although inputs to and outputs from ecosystems are instrumental to understanding sources and sinks of nutrients and other elements , uncertainty in these fluxes is rarely reported in...
Flux of CO2 from the forest soil surface (\({\text{F}}_{{{\text{CO}}_{ 2} }}\)) reflects the activity of roots and microbes responding to plant and soil properties that are influenced by global changes such as nitrogen deposition and increasing temperature and atmospheric CO2. We added low levels of N (3 g/m2-year), P (1 g/m2-year) or N + P to thir...
Measurements of tree tissue chemistry are influenced by the precision and accuracy of laboratory analyses, sampling position within the tree, variation among replicate trees of the same species, and variation from year to year. We characterized these sources of uncertainty for six northern hardwood species and compared them with observed rates of l...
Background/Questions/Methods
Stoichiometry of the soil microbial biomass could contribute to the regulation by soil microbial activities of the availability and recycling of major nutrients like nitrogen (N) and phosphorus (P). The influence of microbial stoichiometry should depend on how constrained biomass element ratios are relative to their env...
Plant nutrient acquisition in forests requires respiration by roots and mycorrhizae. Belowground carbon allocation and soil respiration should thus reflect plant effort allocated to nutrient uptake, for example in conditions of different nutrient availabilities controlled by site quality or stand history. Soil respiration, belowground C allocation,...
Understanding how plants are constructed—i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals—is essential for modeling plant growth, carbon stocks, and energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among speci...
Understanding how plants are constructed—i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals—is essential for modeling plant growth, carbon stocks, and energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting species and among speci...
Understanding how plants are constructed; i.e., how key size dimensions and the amount of mass invested in different tissues varies among individuals; is essential for modeling plant growth, estimating carbon stocks, and mapping energy fluxes in the terrestrial biosphere. Allocation patterns can differ through ontogeny, but also among coexisting sp...
Previous studies have attempted to link foliar resorption of nitrogen and phosphorus to their respective availabilities in soil, with mixed results. Based on resource optimization theory, we hypothesized that the foliar resorption of one element could be driven by the availability of another element. We tested various measures of soil N and P as pr...
Understanding how soil nutrients affect sap sweetness of sugar maples (Acer saccharum Marsh.) is important for producing maple syrup, an economically important non-timber forest product in the northeastern USA and southeastern Canada. Sugar maples were sampled for sap sweetness in 21 plots distributed across five stands in the White Mountains of Ne...
Uncertainty in the estimation of hydrologic export of solutes has never been fully evaluated at the scale of a small‐watershed ecosystem. We used data from the Gomadansan Experimental Forest, Japan, Hubbard Brook Experimental Forest, USA, and Coweeta Hydrologic Laboratory, USA, to evaluate many sources of uncertainty, including the precision and ac...
The high value of sugar maple logs and lumber depends on the wood being light-colored and clear of defects. Predicting the size of dark hearts in trees before they are harvested is very important to foresters, forest landowners, and sawmills. We investigated many possible predictors of the heart size of sugar maple in 10 sites in New York State. He...
Sugar maple (Acer saccharum Marsh.), a keystone species of northern hardwood forests, is susceptible to decline, especially on sites low in the soil base cations calcium (Ca) and magnesium (Mg). A common stressor of sugar maple is forest tent caterpillar (FTC; Malacosoma disstria Hubner), an indigenous defoliator. The recent outbreak of FTC (2002-2...
Background/Question/Methods
Leaf litterfall constitutes one of the largest annual nutrient fluxes in temperate forests. The calculation of litterfall nutrient fluxes requires estimates of litterfall mass and litterfall chemistry. Both of these properties vary across time and space. Understanding the relative contribution of these sources of varia...
Background/Question/Methods
Although temperate forests have long been thought to be primarily nitrogen limited, resource optimization theory suggests that ecosystem productivity should be co-limited by multiple nutrients. Mechanisms for maintaining stochiometric balance in ecosystems include nutrient resorption in senescing tissues, uptake by pla...
Background/Question/Methods
Nutrient budgets are commonly constructed for forest ecosystems but rarely are they monitored over time with attention to changes in nutrient concentrations. Often, nutrient accumluation rates are estimated based on changes in mass by assuming that nutrient concentrations are constant. Foliage is the tree tissue that i...