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At least 37 records · Page 2Linked to original sources
USGS2002

Avian species richness in different-aged stands of riparian forest along the middle Rio Grande, New Mexico

Riparian forests are important for maintaining vertebrate species richness in the southwestern United States, but they have become restricted in distribution due to both historical and current management practices. In order to counteract continued loss of this habitat, several mitigation programs were developed in the middle Rio Grande Valley of New Mexico. Three areas ranging from 50 to 140 ha were revegetated with native trees using pole planting and cattle exclosures, and changes in vegetation structure were quantified after 2, 3, and 5 years of growth. As expected, the older site contained the most heterogeneous mix of plant species and the greatest structural diversity. We compared year-round avian use of the revegetated sites with a mature cottonwood forest site of approximately 30 years of age. As the revegetated sites matured and salient habitat features changed, the population dynamics of individual avian species and patterns of guild structure varied. The older revegetated sites showed a greater similarity to the mature cottonwood site, suggesting that reclamation efforts established quality riparian habitats for birds in as little as 5 years. The revegetated sites appeared especially important for Neotropical-migrant birds. We suggest that a mosaic of riparian woodlands containing mixtures of native tree and shrub species of different size classes is necessary to maintain avian species richness in the middle Rio Grande drainage, and probably throughout the southwestern United States.

New Mexico↗
USGS2000

Dissolved organic nitrogen budgets for upland, forested ecosystems in New England

Relatively high deposition of nitrogen (N) in the northeastern United States has caused concern because sites could become N saturated. In the past, mass-balance studies have been used to monitor the N status of sites and to investigate the impact of increased N deposition. Typically, these efforts have focused on dissolved inorganic forms of N (DIN = NH4-N + NO3-N) and have largely ignored dissolved organic nitrogen (DON) due to difficulties in its analysis. Recent advances in the measurement of total dissolved nitrogen (TDN) have facilitated measurement of DON as the residual of TDN - DIN. We calculated DON and DIN budgets using data on precipitation and streamwater chemistry collected from 9 forested watersheds at 4 sites in New England. TDN in precipitation was composed primarily of DIN. Net retention of TDN ranged from 62 to 89% (4.7 to 10 kg ha-1 yr-1) of annual inputs. DON made up the majority of TDN in stream exports, suggesting that inclusion of DON is critical to assessing N dynamics even in areas with large anthropogenic inputs of DIN. Despite the dominance of DON in streamwater, precipitation inputs of DON were approximately equal to outputs. DON concentrations in streamwater did not appear significantly influenced by seasonal biological controls, but did increase with discharge on some watersheds. Streamwater NO3-N was the only fraction of N that exhibited a seasonal pattern, with concentrations increasing during the winter months and peaking during snowmelt runoff. Concentrations of NO3-N varied considerably among watersheds and are related to DOC:DON ratios in streamwater. Annual DIN exports were negatively correlated with streamwater DOC:DON ratios, indicating that these ratios might be a useful index of N status of upland forests.

Biogeochemistry↗
USGS2017

Development of the mixed conifer forest in northern New Mexico and its relationship to Holocene environmental change

Chihuahueños Bog (2925 m) in the Jemez Mountains of northern New Mexico contains one of the few records of late-glacial and postglacial development of the mixed conifer forest in southwestern North America. The Chihuahueños Bog record extends to over 15,000 cal yr BP. An Artemisia steppe, then an open Picea woodland grew around a small pond until ca. 11,700 cal yr BP when Pinus ponderosa became established. C/N ratios, δ 13 C and δ 15 N values indicate both terrestrial and aquatic organic matter was incorporated into the sediment. Higher percentages of aquatic algae and elevated C/N ratios indicate higher lake levels at the opening of the Holocene, but a wetland developed subsequently as climate warmed. From ca. 8500 to 6400 cal yr BP the pond desiccated in what must have been the driest period of the Holocene there. C/N ratios declined to their lowest Holocene levels, indicating intense decomposition in the sediment. Wetter conditions returned after 6400 cal yr BP, with conversion of the site to a sedge bog as groundwater levels rose. Higher charcoal influx rates after 6400 cal yr BP probably result from greater biomass production rates. Only minor shifts in the overstory species occurred during the Holocene, suggesting that mixed conifer forest dominated throughout the record.

Quaternary Research↗
USGS2005

Effects of a clearcut on the net rates of nitrification and N mineralization in a northern hardwood forest, Catskill Mountains, New York, USA

The Catskill Mountains of southeastern New York receive among the highest rates of atmospheric nitrogen (N) deposition in eastern North America, and ecosystems in the region may be sensitive to human disturbances that affect the N cycle. We studied the effects of a clearcut in a northern hardwood forest within a 24-ha Catskill watershed on the net rates of N mineralization and nitrification in soil plots during 6 years (1994-1999) that encompassed 3-year pre- and post-harvesting periods. Despite stream NO3- concentrations that increased by more than 1400 ??mol l-1 within 5 months after the clearcut, and three measures of NO3- availability in soil that increased 6- to 8-fold during the 1st year after harvest, the net rates of N mineralization and nitrification as measured by in situ incubation in the soil remained unchanged. The net N-mineralization rate in O-horizon soil was 1- 2 mg N kg-1 day-1 and the net nitrification rate was about 1 mg N kg-1 day-1, and rates in B-horizon soil were only one-fifth to one-tenth those of the O-horizon. These rates were obtained in single 625 m2 plots in the clearcut watershed and reference area, and were confirmed by rate measurements at 6 plots in 1999 that showed little difference in N-mineralization and nitrification rates between the treatment and reference areas. Soil temperature increased 1 ?? 0.8??C in a clearcut study plot relative to a reference plot during the post-harvest period, and soil moisture in the clearcut plot was indistinguishable from that in the reference plot. These results are contrary to the initial hypothesis that the clearcut would cause net rates of these N-cycling processes to increase sharply. The in situ incubation method used in this study isolated the samples from ambient roots and thereby prevented plant N uptake; therefore, the increases in stream NO3- concentrations and export following harvest largely reflect diminished uptake. Changes in temperature and moisture after the clearcut were insufficient to measurably affect the net rates of N mineralization and nitrification in the absence of plant uptake. Soil acidification resulting from the harvest may have acted in part to inhibit the rates of these processes. ?? Springer 2005.

Biogeochemistry↗
USGS2017

Urban forest management in New England: Towards a contemporary understanding of tree wardens in Massachusetts communities

In the New England states, tree wardens are local officials responsible for the preservation, maintenance and stewardship of municipal public trees. This study explores the emerging professional challenges, duties and responsibilities of tree wardens, from the subject’s point of view, by conducting in-person, semi-structured qualitative research interviews with 50 tree wardens throughout Massachusetts. Many of the findings corroborate previous literature, including that tree wardens are typically housed in a municipal department (often public works or highway), that tree wardens routinely interact with a wide variety of local organisations (representatives from other municipal departments, community volunteer associations) and that as community size increases, tree wardens typically have access to a greater pool of resources to carry out urban forest management. A newer finding is that the subject of urban forest health arose as a topic of great importance for tree wardens, as nearly all interviewees ( n = 49) indicated that they monitor for urban forest pests and that they would like further continuing education concerning this subject.

Massachusetts↗
USGS2003

Assessment of forest fragmentation in southern New England using remote sensing and geographic information systems technology

Spatial patterns and rates of forest fragmentation were assessed using digital remote sensing data for a region in southern New England that included 157 townships in southern New Hampshire and northeastern Massachusetts. The study area has undergone marked population increases over the last several decades. Following classification of 1973 and 1988 Landsat Multispectral Scanner data into forest and nonforest classes, data were incorporated into a geographic information system. The natural logarithms of forest area to perimeter ratios, referred to as the forest continuity index, were used to assess patterns and trends of forest fragmentation across the region Forest continuity index values were extracted from each township for both data sets and compared with population data. Forest continuity index values were found to decrease with increasing population density until about 200 persons per square kilometer, after which the relationship stabilized. With slight population increases at low densities forest continuity index values declined sharply, implying abrupt increases in forest fragmentation. Results from the study indicated good negative correlations (r 2 values of 0.81 and 0.77) between the Multispectral Scanner-derived forest continuity index and natural logs of township population density. Socioeconomic indicators such as affluence and commuting patterns did not appear to correlate well with forest fragmentation estimates. Decreases in forest continuity index values occurred throughout much of the study region between 1973 and 1988, suggesting that forest fragmentation is occurring over large regions within the eastern United States. It is technologically feasible to assess patterns and rates of forest fragmentation across much larger areas than analyzed in this study; such analyses would provide useful overviews enabling objective assessment of the magnitude of forest fragmentation.

Massachusetts, New Hampshire↗
USGS2021

Changes in forest connectivity from beech bark disease in Pictured Rocks National Lakeshore in the Upper Peninsula of Michigan

Within the forests of Pictured Rocks National Lakeshore, biologists are trying to understand the effects beech bark disease has on wildlife species, especially species that need forest connectivity to thrive. This project used aerial imagery collected in 2005, shortly after beech bark disease infestation, and satellite imagery from 2018. The 2018 imagery represents present day conditions and was used to locate forest canopy gaps through object-based image analysis. Forest canopy gaps were identified using the multiresolution segmentation algorithm within Trimble’s eCognition software. A time change analysis was completed to understand how the forest canopy had changed from 2005 to 2018. The analysis showed areas that had maintained forest canopy, maintained a forest canopy gap, created a new canopy gap (closed forest canopy in 2005 but open canopy gap in 2018), or created new forest canopy (open canopy gap in 2005 but closed forest canopy in 2018). There were 9,127 acres of forest canopy lost, and 72.8 percent of that lost canopy occurred in a forest type where Fagus grandifolia Ehrh. (American beech) is a common tree species. The datasets developed through this project can enhance knowledge of where canopy gaps exist and help place focus on certain areas for wildlife studies. In addition, these datasets can be used in future studies to monitor the health of the forest and conduct additional change analyses.

Michigan↗
USGS1992

Aluminum in soil solutions from a subalpine spruce-fir forest at Whiteface Mountain, New York

Direct or indirect Al toxicity has been suggested as a principal factor in forest tree declines. We monitored ambient soil solutions in undisturbed and experimentally manipulated soils from a fir [ Abies balsamea (L.) Mill.]-spruce forest on Whiteface Mountain, NY, in order to characterize soil solution Al concentrations over a range of acid anion loadings. Under both natural and experimental conditions total Al and labile Al concentrations rarely exceeded values (180–250 µmol L −1 ) associated with reduced root growth in red spruce ( Picea rubens Sarg.). Over a 2-yr period ambient soil solutions averaged 76 and 46 µmol L −1 total Al in the organic and mineral horizons, respectively. The highest monthly mean concentrations occurred in winter. Disturbance-induced NO 3 accumulation and simulated acid rain applications produced higher peak Al values in experimental plots than were observed in undisturbed and untreated plots. Although soils of the fir-spruce zone exhibited the potential to yield solutions with phytotoxic Al concentrations, it appears that such concentrations are both spatially and temporally limited and infrequently present a direct stress to root growth in red spruce.

New York↗
USGS2006

Towards sustainable management of Louisiana's coastal wetland forests: Problems, constraints, and a new beginning

Over 345,000 ha of forested swamps occur throughout the Mississippi River Deltaic Plain. Natural and anthropogenic changes in hydrology and geomorphology at local and landscape levels have reduced the productivity in many of these coastal wetland forests areas and have caused the complete loss of forest cover in some places. A summary and interpretation of the available science, suggestions for policy change, and a multidisciplinary (multi-responsibility) approach were needed to address these issues [in the context of private land]. In response, the Louisiana Governor's office formed a Coastal Wetland Forest Conservation and Use Science Working Group (SWG) and an associated Advisory Panel to provide the Governor with information and suggestions of strategies for environmental and economic utilization, conservation, and protection of Louisiana's coastal wetland forest ecosystem in the long-term. The process of engaging scientists, resource managers, and other stakeholders in this effort is described, and the recommendations of the SWG are presented relative to forestry practices and the potential for sustainable management of coastal wetland forests.

Louisiana↗
USGS2026

Climate change vulnerability assessment for guiding ecosystem restoration in fire-prone landscapes of the western U.S.

Climate-driven alterations to fire regimes challenges forest management and restoration in the western United States, where increased wildfire severity threatens ecosystem integrity and resilience. In this study, we demonstrate the application of the FireCLIME (Fire-Climate-Landscape Interactions in Montane Ecosystems) Vulnerability Assessment (VA) as a decision-support tool for evaluating management actions, including restoration strategies, under climate uncertainty. Through collaborative workshops with USDA Forest Service managers, we assessed three project areas in two national forests: Lincoln National Forest (LNF, New Mexico) and Bighorn National Forest (BNF, Wyoming). These two locations represent distinct climate zones, forest ecosystems, and fire regimes. We examined how changing climate and fire regimes affect ecosystem vulnerability with the FireCLIME VA, which integrates exposure to climate and fire regime changes, ecosystem response factors, and adaptive capacity via management intervention to compare vulnerability outcomes relative to desired future conditions (DFC). Results revealed that forests that departed more from historical conditions (LNF) exhibited greater vulnerability. Soil burn severity and associated erosion emerged as common vulnerability drivers across all sites. For both forests, treatments were able to reduce departure from DFC. Treatment effectiveness varied by ecosystem type; some interventions demonstrated broad capacity to lower vulnerability and achieve DFC for a wide range of components, while others had more targeted effects for specific components. This assessment framework reveals substantial synergy between climate adaptation planning and restoration ecology principles, suggesting that vulnerability assessments can effectively guide restoration planning under climate uncertainty by balancing risk reduction with ecosystem resilience enhancement.

New Mexico, Wyoming↗
USGS2006

Influence of alternative silviculture on small mammals

HIGHLIGHT: A variety of harvest methods promote diversity within forests while still generating income. For example, recent studies have shown that when dead wood is left on the forest floor during harvest, biodiversity increases. A new Cooperative Forest Ecosystem Research (CFER) program fact sheet summarizes how small mammals respond to dead wood in forests that are harvested with alternative methods. CFER is developing a series of fact sheets about responses to changes in young western Oregon forests. The fact sheets are designed to help resource managers balance management needs, including timber and wildlife. The USGS provides a primary source of financial support for CFER, a consortium of federal and state partners conducting research in support of the Northwest Forest Plan.

Fact Sheet↗
USGS2015

Record long-distance movement of a Deer Mouse, Peromyscus maniculatus , in a New England montane boreal forest

We report a single-season, non-homing movement of 4287 ± 10 m by an adult male Deer Mouse, Peromyscus maniculatus , in western Maine, United States, in summer 2014. The movement was achieved in two stages: 927 ± 3 m in four days and an additional 3360 ± 10 m in 44 days. This is approximately 40% greater than the previously documented maximum linear movement for an individual of this species.

Maine↗
USGS2001

Catchment-scale variation in the nitrate concentrations of groundwater seeps in the Catskill Mountains, New York, U.S.A.

Forested headwater streams in the Catskill Mountains of New York show significant among-catchment variability in mean annual nitrate (NO3-) concentrations. Large contributions from deep groundwater with high NO3- concentrations have been invoked to explain high NO3- concentrations in stream water during the growing season. To determine whether variable contributions of groundwater could explain among-catchment differences in streamwater, we measured NO3- concentrations in 58 groundwater seeps distributed across six catchments known to have different annual average streamwater concentrations. Seeps were identified based on release from bedrock fractures and bedding planes and had consistently lower temperatures than adjacent streamwaters. Nitrate concentrations in seeps ranged from near detection limits (0.005 mg NO3--N/L) to 0.75 mg NO3--N/L. Within individual catchments, groundwater residence time does not seem to strongly affect NO3- concentrations because in three out of four catchments there were non-significant correlations between seep silica (SiO2) concentrations, a proxy for residence time, and seep NO3- concentrations. Across catchments, there was a significant but weak negative relationship between NO3- and SiO2 concentrations. The large range in NO3- concentrations of seeps across catchments suggests: 1) the principal process generating among-catchment differences in streamwater NO3- concentrations must influence water before it enters the groundwater flow system and 2) this process must act at large spatial scales because among-catchment variability is much greater than intra-catchment variability. Differences in the quantity of groundwater contribution to stream baseflow are not sufficient to account for differences in streamwater NO3- concentrations among catchments in the Catskill Mountains.

Water, Air, & Soil Pollution↗
USGS2016

Groundwater level trends and drivers in two northern New England glacial aquifers

We evaluated long-term trends and predictors of groundwater levels by month from two well-studied northern New England forested headwater glacial aquifers: Sleepers River, Vermont, 44 wells, 1992-2013; and Hubbard Brook, New Hampshire, 15 wells, 1979-2004. Based on Kendall Tau tests with Sen slope determination, a surprising number of well-month combinations had negative trends (decreasing water levels) over the respective periods. Sleepers River had slightly more positive than negative trends overall, but among the significant trends ( p < 0.1), negative trends dominated 67 to 40. At Hubbard Brook, negative trends outnumbered positive trends by a nearly 2:1 margin and all seven of the significant trends were negative. The negative trends occurred despite generally increasing trends in monthly and annual precipitation. This counterintuitive pattern may be a result of increased precipitation intensity causing higher runoff at the expense of recharge, such that evapotranspiration demand draws down groundwater storage. We evaluated predictors of month-end water levels by multiple regression of 18 variables related to climate, streamflow, snowpack, and prior month water level. Monthly flow and prior month water level were the two strongest predictors for most months at both sites. The predictive power and ready availability of streamflow data can be exploited as a proxy to extend limited groundwater level records over longer time periods.

New Hampshire, Vermont↗