Declining nitrogen (N) availability relative to plant demand, known as N oligotrophication, is a widespread phenomenon that has been particularly well documented in northern hardwood forests of the northeast U.S. It is hypothesized that later fall senescence contributes to this trend by increasing tree resorption of N, resulting in higher carbon:nitrogen ratios (C:N) in litterfall and reduced N availability in soil. To examine the effects of litterfall C:N on soil N cycling, we conducted a litter quality manipulation experiment comparing low C:N and high C:N litter with native litter along an elevation and aspect gradient at Hubbard Brook Experimental Forest, NH, USA. We found that potential net ammonification and mineralization rates were positively correlated with litter N and negatively correlated with litter C:N under high C:N litter, but these relationships were not present under native or low C:N litter. Differences in nitrate pools and net mineralization rates between high- and low-quality litter treatments were greater at colder sites where native litterfall tends to have lower C:N than at low elevation sites. Together, these results demonstrate that higher C:N litter and a warming climate may contribute to N oligotrophication through effects on microbially driven N cycling rates in organic soils.

Disturbance creates structural legacies that are important drivers of functional and compositional stabilities in forested ecosystems. We used an experimental ice storm disturbance to evaluate effects of disturbance severity on structural legacies and their functional consequences. We evaluated canopy structural characteristics (height, density, openness, and complexity) before and after disturbance using data from terrestrial LiDAR. We compared trajectories of structural characteristics and functional outcomes (composition, mortality, and productivity) among treatments and relative to controls. We found significant post-disturbance change for all canopy structural characteristics especially at higher severity levels, with persistent legacy effects on mean canopy height and canopy complexity. There were limited changes in biomass, productivity, and composition, and mortality did not vary significantly among treatments. There was limited evidence for linkages between structural and functional responses, but plots that retained greater complexity had higher stability of net primary productivity. Our findings indicate persistent structural legacies associated with ice storm disturbance, but declining structural legacies over time may affect interactions with subsequent disturbance or stressors. Improved understanding of these trajectories could help with predicting outcomes of changing disturbance regimes associated with global change.

Ice storms might sound fascinating, but for forests, they are not as cool as they seem! Ice storms happen when freezing rain coats trees, branches, and the forest floor in a shiny, frozen glaze. These storms can be a big deal because they can affect our forests and the things we care about, like, wood, wildlife, and places for recreation. Despite this, we do not know very much about how ice storms affect forests. Scientists at the Hubbard Brook Experimental Forest, New Hampshire (USA), decided to learn more. They used fire-fighting pumps and hoses to create experimental ice storms in the forest during the winters of 2016 and 2017. They found that these experimental storms caused a lot of short- and long-term damage to trees, including breaking of twigs and branches. In a nutshell, ice storms are not just about frozen beauty—they have real consequences for our forests and species that are not used to ice!

Remote sensing (RS) and Geographic Information Systems (GISs) provide significant opportunities for monitoring and managing natural resources across various temporal, spectral, and spatial resolutions. There is a critical need for natural resource managers to understand the expanding capabilities of image sources, analysis techniques, and in situ validation methods. This article reviews key image analysis tools in natural resource management, highlighting their unique strengths across diverse applications such as agriculture, forestry, water resources, soil management, and natural hazard monitoring. Google Earth Engine (GEE), a cloud-based platform introduced in 2010, stands out for its vast geospatial data catalog and scalability, making it ideal for global-scale analysis and algorithm development. ENVI, known for advanced multi- and hyperspectral image processing, excels in vegetation monitoring, environmental analysis, and feature extraction. ERDAS IMAGINE specializes in radar data analysis and LiDAR processing, offering robust classification and terrain analysis capabilities. Global Mapper is recognized for its versatility, supporting over 300 data formats and excelling in 3D visualization and point cloud processing, especially in UAV applications. eCognition leverages object-based image analysis (OBIA) to enhance classification accuracy by grouping pixels into meaningful objects, making it effective in environmental monitoring and urban planning. Lastly, QGIS integrates these remote sensing tools with powerful spatial analysis functions, supporting decision-making in sustainable resource management. Together, these tools when paired with in situ data provide comprehensive solutions for managing and analyzing natural resources across scales.

Remote sensing (RS) and Geographic Information Systems (GIS) provide significant opportunities for monitoring and managing natural resources across various temporal, spectral, and spatial resolutions. There is a critical need for natural resource managers to understand the expanding capabilities of image sources, analysis techniques, and in-situ validation methods. This article reviews a range of image analysis tools applicable to natural resource management, including agriculture, water, forests, soil, and natural hazards, and compares their functionalities. Our study highlights that Google Earth Engine (GEE) is favored for wide-area analysis due to its extensive coverage and free access. Global Mapper excels in 3D and light detection and ranging (LIDAR) data, environment for visualizing images (ENVI) specializes in multi- and hyperspectral image processing, ERDAS IMAGINE is optimal for radar data, and eCognition is used for object-based image analysis. The article emphasizes the importance of in-situ validation data, which provides essential ground truth information to calibrate and validate RS models, thereby enhancing accuracy. Understanding these tools and integrating them with in-situ validation techniques enables natural resource managers to improve their monitoring and decision-making processes, facilitating effective collaboration with RS researchers.

We evaluated shoot nonstructural carbohydrate (NSC) concentrations, stem wound closure, and radial growth of sugar maple ( Acer saccharum Marsh.) and red maple ( Acer rubrum L.) trees in a novel ice storm experiment in which five storm treatments (0, 6.4, 12.7, and 19.1 mm of radial ice accretion in 1 year and 12.7 mm of ice in two consecutive years) were applied within a mature northern hardwood forest. We tested for changes in physiology at two levels: (1) associated with plot-level ice treatments and (2) with crown damage classes of individual trees. Few differences in NSC or wound closure associated with treatment were found. Growth decreased for red maple in the medium and high treatments and sugar maple in the high treatment but no other treatments. Changes in physiology were more evident when assessed using crown damage classes. Two NSC components were elevated in sugar and red maples with high (≥50%) crown damage. Wound closure was less for red maples with high damage, and separation among damage classes was even greater for sugar maple. Red maples with moderate (<50%) and high crown damage showed gradually declining growth, whereas sugar maples with high damage showed ∼80% reduction in growth the first year after injury.

The increase in the frequency and severity of water crises around the world necessitates maintaining or augmenting investments in the hydrologic sciences, including in a trained, diverse workforce. The USDA Forest Service operates a network of 85 Experimental Forests and Ranges, Experimental Watersheds, and cooperating sites (EFRs), 31 of which include long-term hydrologic studies (HydroEFRs). The HydroEFRs are centers for hydrologic science and education and play a key role informing watershed policy and management. The goals of this study were to understand (1) how, broadly, the women associated with the HydroEFRs (including women in the Forest Service workforce and women with cooperating agencies or universities who have worked at HydroEFRs) have contributed to hydrologic sciences and (2) how, more specifically, the number and roles of women in the Forest Service workforce associated with the HydroEFRs have changed over time. Data were collected from the EFR Data Explorer, the USDA Forest Service Human Resources Management (HRM) Data Metrics and Analysis Team (DMAT), literature reviews, and questionnaires to USDA EFR scientists-in-charge and to women who were or had been involved in hydrologic sciences at EFRs. Results showed that women associated with the HydroEFRs have made significant contributions to the hydrologic sciences, including authoring or co-authoring over 3,000 publications, with over 170,000 citations since 1977 and an H-index of 181. In their own words, the women indicated that they were also active in contributing to hydrologic fieldwork, providing stewardship for long-term data, and contributing to the social capital of the HydroEFRs through teamwork, collaboration, and mentoring. For the Forest Service, trends in employment records from 1992 through 2021 showed a 55% contraction of the entire FS R&D workforce, including a 59% loss in the number of women in the FS R&D workforce, a 50% loss in the number of women associated with HydroEFR duty stations, and a 26% loss in the number of women in hydrology positions. During this period, there was a greater loss of both women and men in lower-graded positions relative to higher-graded positions in the FS R&D workforce, with serial implications for the ability of the workforce to collect data, produce basic science publications, and conduct syntheses. Although the ratio of women:men declined across the Forest Service and FS R&D, the ratio of women:men increased at the HydroEFRs (driven by a higher ratio of women:men at higher grade levels) and for management positions within FS R&D and at the HydroEFRs.When asked, women valued their contributions to the hydrologic sciences and envisioned a more equitable future for women in hydrology. Overall, results show that HydroEFRs have played an important role in advancing the careers of women in the hydrologic sciences, who, in turn, have contributed to the groundbreaking hydrologic research that occurs at these long-term research sites. As water crises around the world continue to escalate, building a strong, diverse workforce in the hydrologic sciences and supporting the places where they can conduct their research is important.

© 2023 American Meteorological Society. This published article is licensed under the terms of the default AMS reuse license. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). Corresponding author: Daniel Chavas, drchavas@gmail.com

Extreme weather events, such as ice storms, are increasing and have potentially large impacts on forests, including belowground structures such as fine roots and mycorrhizal fungi. Many forest trees rely on the mutualistic relationship between mycorrhizal fungi and plants; a relationship that, when disrupted, can negatively impact tree net primary productivity. We took advantage of a large-scale ice storm manipulation in the northeastern United States to test the hypothesis that increasing ice storm intensity and frequency would reduce ectomycorrhizal fungal root tips per unit root length and arbuscular mycorrhizal fungal structures per unit root length, hereafter colonization. We found that ice storm intensity reduced spring ectomycorrhizal fungal and arbuscular mycorrhizal fungal colonization. However, these patterns changed in the fall, where ice storm intensity still reduced ectomycorrhizal fungal root tips, but arbuscular mycorrhizal fungal colonization was higher in ice storm treatments than controls. The amount of ectomycorrhizal fungal root tips and arbuscular mycorrhizal fungal colonization differed seasonally: ectomycorrhizal fungal root tips were 1.7x higher in the spring than in the fall, while arbuscular mycorrhizal fungal colonization was 3x higher in the fall than in the spring. Our results indicate that mycorrhizal fungal colonization responses to ice storm severity vary temporally and by mycorrhizal fungal type. Further, arbuscular mycorrhizal fungi may recover from ice storms relatively quickly, potentially aiding forests in their recovery, whereas ice storms may have a long lasting impact on ectomycorrhizal fungi.

Climate-smart forestry (CSF) is an emerging branch of sustainable adaptive forest management aimed at enhancing the potential of forests to adapt to and mitigate climate change. It relies on much higher data requirements than traditional forestry. These data requirements can be met by new devices that support continuous, in situ monitoring of forest conditions in real time. We propose a comprehensive network of sensors, i.e., a wireless sensor network (WSN), that can be part of a worldwide network of interconnected uniquely addressable objects, an Internet of Things (IoT), which can make data available in near real time to multiple stakeholders, including scientists, foresters, and forest managers, and may partially motivate citizens to participate in big data collection. The use of in situ sources of monitoring data as ground-truthed training data for remotely sensed data can boost forest monitoring by increasing the spatial and temporal scales of the monitoring, leading to a better understanding of forest processes and potential threats. Here, some of the key developments and applications of these sensors are outlined, together with guidelines for data management. Examples are given of their deployment to detect early warning signals (EWS) of ecosystem regime shifts in terms of forest productivity, health, and biodiversity. Analysis of the strategic use of these tools highlights the opportunities for engaging citizens and forest managers in this new generation of forest monitoring.

Long-term, place-based research programs in the National Science Foundation-supported Long Term Ecological Research (LTER) Network have had profound effects on public policies and practices in land use, conservation, and the environment. While less well known than their contributions to fundamental ecological science, LTER programs’ commitment to serving broad public interests has been key to helping achieve their mission to advance basic science that supports society’s need to address major environmental challenges. Several attributes of all LTER programs are critical to these accomplishments: highly credible science, strong site-level leadership, long-term environmental measurements of ecosystem attributes that are relevant to the public and to resource managers, and effective and accessible information that supports sound management practices. Less recognized attributes of three case study LTER sites (Andrews Forest, Harvard Forest, Hubbard Brook) which have contributed to major impacts include strong interdisciplinary research communities with cultures of openness, dispersed leadership within those communities, a commitment to carry science perspectives to society through multiple governance processes, strong public-private partnerships, and communications programs that facilitate the exchange of information and perspectives among science communities, policy-makers, land managers, and the public. Taken together, these attributes of sites drive on-the-ground outcomes. These case studies reveal a virtue of the long-term nature of LTER not anticipated when the program began: that the decades-long engagement of a place-based, science community can have a major impact on environmental policies and practices. These activities, and the cultivation of science communities that can accomplish them, go beyond the initial directives and review criteria for LTER site proposals and programs.

Large-scale disturbances such as ice storms may increase in frequency and intensity as climate changes. While disturbances are a natural component of forest ecosystems, climatically driven alteration to historical patterns may impart fundamental change to ecosystem function. At Hubbard Brook Experimental Forest, NH, experimental ice storms of varying severity were applied to replicate plots of mature northern hardwoods to quantify their effects on forested ecosystems. We assessed ice storm treatment effects on insectivorous foliage-gleaning birds and evaluated insectivore predation on model caterpillars in the understory vegetation. These birds are charismatic, of conservation concern, and are major predators of caterpillars. In turn, lepidopterans are the dominant herbivores in temperate forests and are integral to ecosystem function. We predicted that avian abundance would increase due to additional structural heterogeneity caused by ice treatments, with a concomitant increase in caterpillar predation. Point counts were used to measure insectivorous bird activity in the ice storm experiment plots and additional control plots before and after treatments. We deployed and retrieved plasticine model caterpillars and estimated predation from characteristic marks to these surrogates. Abundance of foliage-gleaning birds was higher in the ice storm plots and birds responded to treatments as a single diffuse disturbance rather than on an individual plot level. All species except one were observed both before and after the ice treatments. Surprisingly, predation on caterpillar models was unaffected by ice storm treatments but rather was a function of caterpillar density. The increase in avian abundance in the ice storm treatment plots corroborates other studies of bird responses to relatively small-scale disturbances in forests and the limited change in species composition was expected given the plot size. We conclude that ice storms may provide beneficial changes for foliage-gleaning birds in the growing season following the disturbance.

Ice storms can have profound and lasting effects on the structure and function of forest ecosystems in regions that experience freezing conditions. Current models suggest that the frequency and intensity of ice storms could increase over the coming decades in response to changes in climate, heightening interest in understanding their impacts. Because of the stochastic nature of ice storms and difficulties in predicting when and where they will occur, most past investigations of the ecological effects of ice storms have been based on case studies following major storms. Since intense ice storms are exceedingly rare events it is impractical to study them by waiting for their natural occurrence. Here we present a novel alternative experimental approach, involving the simulation of glaze ice events on forest plots under field conditions. With this method, water is pumped from a stream or lake and sprayed above the forest canopy when air temperatures are below freezing. The water rains down and freezes upon contact with cold surfaces. As the ice accumulates on trees, the boles and branches bend and break; damage that can be quantified through comparisons with untreated reference stands. The experimental approach described is advantageous because it enables control over the timing and amount of ice applied. Creating ice storms of different frequency and intensity makes it possible to identify critical ecological thresholds necessary for predicting and preparing for ice storm impacts.

The Hubbard Brook Experimental Forest (HBEF) was established in 1955 by the U.S. Department of Agriculture, Forest Service out of concerns about the effects of logging increasing flooding and erosion. To address this issue, within the HBEF hydrological and micrometeorological monitoring was initiated in small watersheds designated for harvesting experiments. The Hubbard Brook Ecosystem Study (HBES) originated in 1963, with the idea of using the small watershed approach to study element fluxes and cycling and the response of forest ecosystems to disturbances, such as forest management practices and air pollution. Early evidence of acid rain was documented at the HBEF and research by scientists at the site helped shape acid rain mitigation policies. New lines of investigation at the HBEF have built on the long legacy of watershed research resulting in a shift from comparing inputs and outputs and quantifying pools and fluxes to a more mechanistic understanding of ecosystem processes within watersheds. For example, hydropedological studies have shed light on linkages between hydrologic flow paths and soil development that provide valuable perspective for managing forests and understanding stream water quality. New high frequency in situ stream chemistry sensors are providing insights about extreme events and diurnal patterns that were indiscernible with traditional weekly sampling. Additionally, tools are being developed for visual and auditory data exploration and discovery by a broad audience. Given the unprecedented environmental change that is occurring, data from the small watersheds at the HBEF are more relevant now than ever and will continue to serve as a basis for sound environmental decision‐making.

Ice storms are a type of extreme winter weather event common to north temperate and boreal forests worldwide. Recent climate modelling studies suggest that these storms may become more frequent and severe under a changing climate. Compared to other types of storm events, relatively little is known about the direct and indirect impacts of these storms on forests, as naturally occurring ice storms are inherently difficult to study. Here we describe a novel experimental approach used to create a suite of ice storms in a mature hardwood forest in New Hampshire, USA. The experiment included five ice storm intensities (0, 6.4, 12.7 and 19.1 mm radial ice accretion) applied in a single year, and one ice storm intensity (12.7 mm) applied in two consecutive years. Results demonstrate the feasibility of this approach for creating experimental ice storms, quantify the increase in fine and coarse woody debris mass and nutrients transferred from the forest canopy to the soil under the different icing conditions, and show an increase in the damage to the forest canopy with increasing icing that evolves over time. In this forest, little damage occurred below 6.4 mm radial ice accretion, moderate damage occurred with up to 12.7 mm of accretion, and significant branch breakage and canopy damage occurred with 19.1 mm of ice. The icing in consecutive years demonstrated an interactive effect of ice storm frequency and severity such that some branches damaged in the first year of icing appeared to remain in the canopy and then fall to the ground in the second year of icing. These results have implications for National Weather Service ice storm warning levels, as they provide a quantitative assessment of ice-load related inputs of forest debris that will be useful to municipalities creating response plans for current and future ice storms.

Ice storms are important winter weather events that can have substantial environmental, economic, and social impacts. Mapping and assessment of damage after these events could be improved by making ice accretion measurements at a greater number of sites than is currently available. There is a need for low-cost collectors that can be distributed broadly in volunteer observation networks; however, use of low-cost collectors necessitates understanding of how collector characteristics and configurations influence measurements of ice accretion. A study was conducted at the Hubbard Brook Experimental Forest in New Hampshire that involved spraying water over passive ice collectors during freezing conditions to simulate ice storms of different intensity. The collectors consisted of plates composed of four different materials and installed horizontally; two different types of wires strung horizontally; and rods of three different materials, with three different diameters, and installed at three different inclinations. Results showed that planar ice thickness on plates was 2.5-3 times as great as the radial ice thickness on rods or wires, which is consistent with expectations based on theory and empirical evidence from previous studies. Rods mounted on an angle rather than horizontally reduced the formation of icicles and enabled more consistent measurements. Results such as these provide much needed information for comparing ice accretion data. Understanding of relationships among collector configurations could be refined further by collecting data from natural ice storms under a broader range of weather conditions.

In the Sand County Almanac (Leopold 1949), Aldo Leopold writes of the odyssey of element X and thus of the circulation of all nutrient elements as they cycle through the Earth’s forests, rangelands, lakes, and oceans. In mid-century, G.E. Hutchinson, while always one to praise aesthetic values, commented disparagingly about the quantitative science of element cycling, specifically that ecosystem carbon (C) data were “wretchedly inadequate” (Hutchinson 1954). Hutchinson’s comment was not only a complaint but also a challenge to all ecosystem scientists who followed to quantify the Earth’s biogeochemical cycles, for he understood that the resilience and functioning of ecosystems was entirely dependent on how plants, animals, and decomposers used and reused the chemical elements that we call nutrients.

Intermediate disturbances are an important component of many forest disturbance regimes, with effects on canopy structure and related functions that are highly dependent on the nature and intensity of the perturbation. Ice storms are an important disturbance mechanism in temperate forests that often result in moderate-severity, diffuse canopy damage. However, it has not previously been possible to distinguish the specific effect of ice storm intensity (as ice accretion) from predisturbance stand characteristics and physiographic factors. In this study, we utilized a novel experimental ice storm treatment to evaluate the effects of variable ice accretion levels on forest canopy structure. Our results verified significant impacts of ice storm disturbance on near-term canopy structural reorganization. Canopy openness, light transmission, and complexity increased significantly relative to predisturbance baselines and undisturbed controls. We documented variable impacts with disturbance intensity, as significant canopy changes largely occurred with ice accretion levels of ≥12.7 mm. Repeated ice storm disturbance (two consecutive years) had marginal, rather than compounding, effects on forest canopy structure. Our findings are relevant to understanding how ice storms can affect near-term forest canopy structural reorganization and ecosystem processes and add to a growing base of knowledge on the effects of intermediate disturbances on canopy structure.