Search USGS⌕ Search

SEARCH · Search USGS

Results for “New Forests”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
USGS2020

Assessment of methods for soil monitoring in the Adirondack region of New York

Repeated sampling to detect changes in forest soils was rarely used before 1990, but the value of soil monitoring in understanding environmental change is becoming well established. The growing number of resampling studies has shown that sampling designs and procedures must be adapted to the objectives of the monitoring program and the soils being monitored. In the Adirondack region, current priorities include the response of soils to large increases, and more recently, large decreases in acidic deposition, and changes driven by trending climate such as altered pools of soil organic carbon, as well as other unforeseen factors that will occur in the future. To improve methods and assess the feasibility of long-term soil monitoring in the Adirondack region, the United States Geological Survey (USGS) conducted a pilot project to evaluate a new sampling method for characterizing soils on a watershed basis. Results obtained with this new approach, referred to as the ADK sampling method, was compared to methods used in previous sampling conducted in 2004 as part of the Western Adirondack Stream Survey (WASS), and also to previous high-replication pit sampling in the North and South Tributary watersheds of Buck Creek (North Buck and South Buck). The number of sampling locations and spatial distribution of sampling points within watersheds differed among the methods, although pit excavation was used to obtain samples in all cases. In addition, this investigation evaluated the use of small diameter corers as a means to measure forest floor mass with greater accuracy and precision than commonly used methods such as pit excavation. Sufficient statistical power to detect ecologically relevant changes in upper profile horizons (Oe, Oa and upper 10 cm of the B) were achieved with the ADK sampling method that utilized 18 pit excavations per watershed. The sampling locations were organized within each watershed into three study areas (six sampling locations per study area) that represented the primary types of landscape within the watershed. Sampling at 18 locations per watershed was found to be nearly as effective at detecting changes as sampling at 28 locations per watershed. Numerous significant changes (P < 0.10) were detected with both 18 and 28 sampling locations at sampling intervals of 12 to 16 years. The relationship between soil data obtained with the ADK method and stream chemistry at the base of the watershed suggested that this approach adequately characterized soil variability within the watershed for the purpose of studying soil-stream linkages. Significant changes in upper B horizon calcium (P < 0.10) and Oa horizon aluminum (P < 0.01) were detected when the data from the four WASS watersheds were combined with the two Buck Creek watersheds, which suggested that there would be value in resampling other WASS watersheds previously sampled in 2004 to support a regional assessment. Study results support small diameter cores as a useful method to monitor changes in the organic matter mass of the forest floor. This method showed high reproducibility in repeated sampling tests and lower spatial variability in sample data than traditional approaches when compared on a watershed basis. Soil coring is also faster and requires less equipment than pit excavation methods, which makes it more conducive to sampling over large areas. However, organic matter mass of the forest floor determined by coring was consistently less than the values obtained by the ADK sampling method that used pit sampling and vertical horizon measurements, and also literature values of a previous Adirondack study that utilized pit sampling in which the entire horizon was collected over a measured area. However, a high correlation (R2 = 0.87) occurred between organic matter content (expressed as Mg ha-1) determined by coring and the ADK sampling method. Differing methods with regard to where sample could be collected, and how organic matter was collected for chemical analysis were the likely reasons for differences in quantification of forest floor organic mass. Collection of forest floor cores in conjunction with the ADK method is recommended to provide improved sensitivity in detecting changes in the forest floor in proximity of where full analyses of the soil profile are being done. This duel sampling approach represents an optimized method for measuring and understanding how Adirondack soils will change in the future.

New York↗
USGS2017

Tree species preferences of foraging songbirds during spring migration in floodplain forests of the Upper Mississippi River

Floodplain forest of the Upper Mississippi River is important for songbirds during spring migration. However, the altered hydrology of this system and spread of reed canary grass (Phalaris arundinacea) and emerald ash borer (Agrilus planipennis) threaten tree diversity and long-term sustainability of this forest. We estimated tree preferences of songbirds during spring migration 2010–2013 to help guide management decisions that promote tree diversity and forest sustainability and to evaluate yearly variation in tree selection. We used the point center-quarter method to assess relative availability of tree species and tallied bird foraging observations on tree species as well as recording the phenophase of used trees on five 40 ha plots of contiguous floodplain forest between La Crosse, Wisconsin and New Albin, Iowa, from 15 April through 1 June. We quantified bird preferences by comparing proportional use of tree species by each bird species to estimates of tree species availability for all 4 y and for each year separately. Species that breed locally preferred silver maple (Acer saccharinum), which is dominant in this forest. The common transient migrant species and the suite of 17 transient wood warbler species preferred hackberry (Celtis occidentalis) and oaks (Quercus spp.), which are limited to higher elevations on the floodplain. We observed earlier leaf development the warm springs of 2010 and 2012 and later leaf development the cold springs of 2011 and 2013. Yellow-rumped Warbler (Setophaga coronata), American Redstart (S. ruticilla), Warbling Vireo (Vireo gilvus) and Baltimore Oriole (Icterus galbula), and the suite of transient migrant wood warblers spread their foraging efforts among tree species in colder springs and were more selective in warmer springs. All three of the important tree species are not regenerating well on the UMR and widespread die-off of silver maple is possible in 50 y without large scale management.

Minnesota, Wisconsin↗
USGS2013

Moose habitat in Massachusetts: Assessing use at the southern edge of the range

Moose (Alces alces) have recently re-occupied a portion of their range in the temperate deciduous forest of the northeastern United States after a more than 200 year absence. In southern New England, moose are exposed to a variety of forest types, increasing development, and higher ambient temperatures as compared to other parts of their geographic range. Additionally, large-scale disturbances that shape forest structure and expansive naturally occurring shrub-willow communities used commonly elsewhere are lacking. We used utilization distributions to determine third order habitat selection (selection within the home range) of GPS-collared moose. In central Massachusetts, forests regenerating from logging were the most heavily used cover type in all seasons (48 - 63% of core area use). Habitat use of moose in western Massachusetts varied more seasonally, with regenerating forests used most heavily in summer and fall (57 and 46%, respectively), conifer and mixed forests in winter (47 - 65%), and deciduous forests in spring (41%). This difference in habitat selection reflected the transition from northern forest types to more southern forest types across the state. The intensive use of patches of regenerating forest emphasizes the importance of sustainable forest harvesting to moose. This study provides the first assessment of habitat requirements in this southern portion of moose range and provides insights into re-establishment of moose in unoccupied portions of its historic range in New York and Pennsylvania.

Massachusetts, New Hampshire, Vermont↗
USGS2025

Ten more years of the golden pheasant (Chrysolophus pictus) on Maui, Hawaiian Islands

Since the introduction of the Golden Pheasant ( Chrysolophus pictus ) to Haleakalā volcano, Maui, three decades ago, subsequent reports have hinted at an expansion of this nascent population. We draw from a variety of data sources to learn about this pheasant's present status on Maui. First, forest bird surveys conducted every five years revealed that the frequency of Golden Pheasant detections has greatly increased, and the bird has both maintained its former distribution and expanded eastward into Haleakalā National Park (NP). Second, reports to eBird from The Nature Conservancy's Waikamoi Preserve, where Golden Pheasants first appeared on Maui, demonstrate that the frequency of observations has increased and is strongly seasonal, predominantly in the spring. Third, autonomous recording units monitoring endangered forest birds recorded pheasants too, adding new locations. Finally, trail cameras set to monitor mammals picked up pheasants as well, showing males of two color morphs: original “wild-type” and “dark-throated.” Trail cameras also documented a small juvenile at Waikamoi Preserve and both females and males in Haleakalā NP. By “connecting the dots” of mapped occurrences, we traced the pheasant's progression through a narrow band of subalpine cloud forest with open understory, extending from Waikamoi Preserve eastward to upper Kīpahulu Valley, a distance of 14 km. In summary, this body of evidence supports the claim that the Golden Pheasant has established a self-sustaining population on Maui, and we propose that the species' success there may be attributed to the minimal influence of predators and the absence of competing gallinaceous birds in its preferred habitat.

Hawaii↗
USGS2019

Forest restoration, wildfire, and habitat selection by female mule deer

Decades of fire suppression, logging, and overgrazing have led to increased densities of small diameter trees which have been associated with decreases in biodiversity, reduced habitat quality for wildlife species, degraded foraging conditions for ungulates, and more frequent and severe wildfires. In response, land managers are implementing forest restoration treatments using prescribed fire and thinning to mitigate the risk of catastrophic wildfires and improve habitat conditions for a variety of wildlife species. We monitored habitat selection by female mule deer ( Odocoileus hemionus ) in relation to forest restoration treatments and wildfires in northern New Mexico in 2015. Our specific objectives were to assess changes in forage abundance and determine habitat selection patterns of mule deer in relation to recent wildfires, forest restoration treatments, including duration of the post-treatment recovery, and other habitat characteristics. Herbaceous forage biomass was greater in wildfire-burned areas than in untreated areas or those treated with prescribed burns or thinning. Oak forage biomass was greater in wildfire-burned areas compared to prescribed burns, forest thinning, and untreated areas. However, thinned areas tended to have higher oak forage biomass than untreated areas. Mule deer selected for areas burned by prescribed fire and generally avoided wildfire-burned and thinned areas <5 years old. Mule deer strongly selected for thinned areas ≥5 years old. At both the landscape and home-range scale, grasslands were avoided during most seasons, pinyon-juniper woodlands were selected in winter, and oak vegetation and mixed-conifer forests were selected during summer. Our data suggests that mule deer may benefit from recent prescribed burns and older forest thinning, but the duration of post-treatment vegetation recovery influences the strength and direction of selection. Knowledge of the short- and long-term effects of restoration treatments will provide managers with the means to make more informed decisions regarding implementation of forest restoration and other vegetation treatments intended to benefit mule deer.

New Mexico↗
USGS2024

Post-fire reference densities for giant sequoia seedlings in a new era of high-severity wildfires

Many forests globally are experiencing increases in large, high-severity wildfires, often with increasingly inadequate post-fire tree regeneration. To identify areas that might need post-fire planting, forest managers have a growing need for seedling reference densities – the natural seedling densities expected to be adequate to regenerate a forest – to compare with observed post-fire seedling densities. The most useful reference densities will meet five criteria: they will (1) be specific to natural post-fire reproduction rather than planted seedlings (because planted seedlings can have substantially greater survival than natural seedlings, thus underestimating adequate natural reproduction), (2) apply to the first few years following fire (when management decisions and actions are most likely), (3) be specific to each of those post-fire years (because post-fire seedling densities can change rapidly with time since fire), (4) be associated with estimates of uncertainty, and (5) include consideration of novel environmental conditions during management applications (because most reference densities will be based on data collected under more environmentally benign conditions). The world’s most massive tree species, the giant sequoia ( Sequoiadendron giganteum ) of California’s Sierra Nevada, recently experienced historically unprecedented wildfires that killed an estimated 13–19% of mature sequoias across their native range. Seedlings germinating after these fires then experienced exceptional summer heat and the two most severe summer droughts of the 121-year historical record. To help inform management responses to these events, we used seedling censuses from past fires (mostly prescribed fires) to calculate sequoia seedling reference densities meeting the five criteria. The reference densities had three striking features, which are partly attributable to giant sequoia’s status as a pioneer species. First, despite being inherently conservative, the reference densities were quite high. For example, mean first-year reference density was 172,599 seedlings ha −1 . Second, reference densities declined precipitously with time since fire: the mean fifth-year reference density was only 5% of the mean first-year density. Third, the reference densities were associated with relatively substantial uncertainty, a consequence of density variations among seedling plots; for example, the 95% credible interval for first-year reference density was 64,377 to 313,438 seedlings ha −1 . Despite this uncertainty, a case-study sequoia grove that recently burned in a high-severity wildfire had second-year post-fire seedling densities that were significantly (and dramatically) lower than the corresponding second-year reference density, suggesting inadequate post-fire reproduction. Our results highlight the value of the five criteria for reference densities – criteria that, in current practice, are rarely all met.

Forest Ecology and Management↗
USGS2014

The 3D Elevation Program: summary for New Mexico

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of New Mexico, elevation data are critical for infrastructure and construction management, natural resources conservation, flood risk management, agriculture and precision farming, geologic resource assessment and hazard mitigation, forest resources management, and other business uses. Today, high-density light detection and ranging (lidar) data are the primary sources for deriving elevation models and other datasets. Federal, State, Tribal, and local agencies work in partnership to (1) replace data that are older and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 (table 1) for the conterminous United States and quality level 5 ifsar data (table 1) for Alaska with a 6- to 10-year acquisition cycle provided the highest benefit/cost ratios.The 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey (USGS), the Office of Management and Budget Circular A&ndash;16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other 3D representations of the Nation&rsquo;s natural and constructed features.

New Mexico↗
USGS2017

Improving predictions of tropical forest response to climate change through integration of field studies and ecosystem modeling

Tropical forests play a critical role in carbon and water cycles at a global scale. Rapid climate change is anticipated in tropical regions over the coming decades and, under a warmer and drier climate, tropical forests are likely to be net sources of carbon rather than sinks. However, our understanding of tropical forest response and feedback to climate change is very limited. Efforts to model climate change impacts on carbon fluxes in tropical forests have not reached a consensus. Here we use the Ecosystem Demography model (ED2) to predict carbon fluxes of a Puerto Rican tropical forest under realistic climate change scenarios. We parameterized ED2 with species-specific tree physiological data using the Predictive Ecosystem Analyzer workflow and projected the fate of this ecosystem under five future climate scenarios. The model successfully captured inter-annual variability in the dynamics of this tropical forest. Model predictions closely followed observed values across a wide range of metrics including above-ground biomass, tree diameter growth, tree size class distributions, and leaf area index. Under a future warming and drying climate scenario, the model predicted reductions in carbon storage and tree growth, together with large shifts in forest community composition and structure. Such rapid changes in climate led the forest to transition from a sink to a source of carbon. Growth respiration and root allocation parameters were responsible for the highest fraction of predictive uncertainty in modeled biomass, highlighting the need to target these processes in future data collection. Our study is the first effort to rely on Bayesian model calibration and synthesis to elucidate the key physiological parameters that drive uncertainty in tropical forests responses to climatic change. We propose a new path forward for model-data synthesis that can substantially reduce uncertainty in our ability to model tropical forest responses to future climate.

Global Change Biology↗
USGS2020

Forest canopy gap dynamics: Quantifying forest gaps and understanding gap – level forest regeneration in Upper Mississippi River floodplain forests

In most forest systems, the dynamics of forest canopy gap development play an important role in the transition from relatively short-lived early successional tree species to longer-lived, late successional tree species. In resilient forest systems, tree seedlings establish within newly created canopy gaps and grow to close the gap within one or two decades of disturbance. However, evidence in portions of the Upper Mississippi River System indicates that floodplain forests do not appear to be following these same trajectories, with canopy gaps instead seeming to fail to recruit new tree seedlings and reverting to non-forested cover types. Because of the heavy dominance of short-lived tree species in current UMRS forests, there is concern that continued failure of canopy gaps to recruit back to forest could be an early indicator of long-term, widespread forest loss as gaps become larger and larger and begin to coalesce into large, non-forested areas. Little research to date has documented either the density and distribution of forest canopy gaps across the UMRS or the vegetative conditions within those gaps to provide an initial assessment of forest dynamics in those areas. The current study utilizes both remotely sensed data and field sampling to assess the conditions of forest canopy gaps within 6 navigation pools on the Upper Mississippi River and one pool on the Illinois River. In general, canopy gap distributions and characteristics are similar across the study, with most pools ranging from 3% to 5% of forest canopy in gaps. Gap sizes are also relatively uniform, with most pools averaging 0.09 to 0.14 ha per gap. The highest proportion of forest cover in canopy gaps at the pool level was driven by the total number of gaps and not gap size, indicating that canopy gap formation in this system is commonly due to individual tree or small clump mortality. Undesirable competing vegetation was dominant in most canopy gaps, with reed canarygrass and native forbs being most prevalent in upper pools and vines most problematic in the lower pools. In the upper pools, very little viable forest regeneration is occurring within canopy gaps. The viability of forest regeneration increases in middle and lower pools, though competing vegetation continues to be a problem. Overall, canopy gaps appear 3 most likely to recruit back to forest in lower pools, and chronic forest loss facilitated by regeneration failures seems most likely in upper pools. However, competing vegetation in lower pools may still interact with woody regeneration to limit effective reestablishment of forest canopy.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗
USGS2012

Monitoring gradual ecosystem change using Landsat time series analyses: case studies in selected forest and rangeland ecosystems

The focus of the study was to assess gradual changes occurring throughout a range of natural ecosystems using decadal Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM +) time series data. Time series data stacks were generated for four study areas: (1) a four scene area dominated by forest and rangeland ecosystems in the southwestern United States, (2) a sagebrush-dominated rangeland in Wyoming, (3) woodland adjacent to prairie in northwestern Nebraska, and (4) a forested area in the White Mountains of New Hampshire. Through analyses of time series data, we found evidence of gradual systematic change in many of the natural vegetation communities in all four areas. Many of the conifer forests in the southwestern US are showing declines related to insects and drought, but very few are showing evidence of improving conditions or increased greenness. Sagebrush communities are showing decreases in greenness related to fire, mining, and probably drought, but very few of these communities are showing evidence of increased greenness or improving conditions. In Nebraska, forest communities are showing local expansion and increased canopy densification in the prairie&ndash;woodland interface, and in the White Mountains high elevation understory conifers are showing range increases towards lower elevations. The trends detected are not obvious through casual inspection of the Landsat images. Analyses of time series data using many scenes and covering multiple years are required in order to develop better impressions and representations of the changing ecosystem patterns and trends that are occurring. The approach described in this paper demonstrates that Landsat time series data can be used operationally for assessing gradual ecosystem change across large areas. Local knowledge and available ancillary data are required in order to fully understand the nature of these trends.

Remote Sensing of Environment↗
USGS2024

Ohi'a lehua (Metrosideros polymorpha): A most resilient and persistent foundation species in Hawaiian forests

Metrosideros polymorpha (‘ōhi‘a, ‘ōhi‘a lehua) is an important foundation species in Hawaiian forest habitats. The genus originated in New Zealand and was dispersed to the Hawaiian archipelago approximately 3.9 million years ago. It evolved into five distinct endemic species and one of these, Metrosideros polymorpha , further differentiated into eight varieties across what are now the main Hawaiian Islands. ‘Ōhi‘a is a tree that has great significance in indigenous Hawaiian culture. It is considered a physical manifestation of several principal Hawaiian deities, and serves a broad range of uses in Hawaiian material culture. It occupies a wide diversity of habitats, extending from sea level to over 2,200 m elevation, occupying habitats that range from extremely wet to dry rainfall zones. It is the dominant or co-dominant tree species in wet and mesic forests and is also one of the first woody species to become established on young lava flows. Although ‘ōhi‘a is a dominant forest tree it also exhibits many characteristics of a pioneer species. ‘Ōhi‘a provides the matrix for a wide diversity of endemic plants and animals found in these habitats and functions as the primary vegetation cover on native Hawaiian watersheds, facilitating groundwater recharge and regulating surface runoff. ‘Ōhi‘a has shown remarkable resilience by recolonizing forests that were opened up by disturbance, such as the widespread ‘ōhi‘a canopy dieback that occurred on East Maui in the 1900s and on the east side of the Island of Hawai‘i in the 1970s. Several human-related conditions threaten the continued stability of Hawaii’s native ecosystems, including invasive plants, plant diseases, introduced animals, and changing climate. The research and conservation legacy of Dr. Dieter Mueller-Dombois helped to expand our knowledge of the ecology and importance of ‘ōhi‘a forests, and to increase awareness and appreciation of the remarkable Hawaiian ecosystems that are unique to the world.

Hawaii↗
USGS1998

Level II scour analysis for Bridge 30 (NEWHTH00050030) on Town Highway 5, crossing the New Haven River, New Haven, Vermont

This report provides the results of a detailed Level II analysis of scour potential at structure NEWHTH00050030 on Town Highway 5 crossing the New Haven River, New Haven, Vermont (figures 1–8). A Level II study is a basic engineering analysis of the site, including a quantitative analysis of stream stability and scour (Federal Highway Administration, 1993). Results of a Level I scour investigation also are included in appendix E of this report. A Level I investigation provides a qualitative geomorphic characterization of the study site. Information on the bridge, gleaned from Vermont Agency of Transportation (VTAOT) files, was compiled prior to conducting Level I and Level II analyses and is found in appendix D. The site is in the Champlain section of the St. Lawrence Valley physiographic province in west-central Vermont. The 115-mi 2 drainage area is in a predominantly rural and forested basin. In the vicinity of the study site, the surface cover is pasture on the right bank upstream and downstream of the bridge while the immediate banks have dense woody vegetation. The upstream left bank is also pasture. The downstream left bank is forested. In the study area, the New Haven River has an incised, sinuous channel with a slope of approximately 0.01 ft/ft, an average channel top width of 127 ft and an average bank height of 5 ft. The channel bed material ranges from silt to cobble with a median grain size (D 50 ) of 20.4 mm (0.067 ft). The geomorphic assessment at the time of the Level I and Level II site visit on June 19, 1996, indicated that the reach was laterally unstable. The stream bends through the bridge and impacts the left bank where there is a cut bank and scour hole. The Town Highway 5 crossing of the New Haven River is a 181-ft-long, two-lane bridge consisting of four 45-ft concrete tee-beam spans (Vermont Agency of Transportation, written communication, December 15, 1995). The opening length of the structure parallel to the bridge face is 175.9 ft. The bridge is supported by vertical, concrete abutments with stone fill spill-through embankments and three concrete piers. The channel is skewed approximately 15 degrees to the opening while the computed opening-skew-to-roadway is 10 degrees. A scour hole 4.5 ft deeper than the mean thalweg depth was observed along the downstream left bank during the Level I assessment. Also observed was a scour hole 1.5 ft deeper than the mean thalweg depth at the upstream end of the middle pier. The only scour protection measure at the site was type-3 stone fill (less than 48 inches diameter) in front of the left and right abutments creating spill through slopes. Additional details describing conditions at the site are included in the Level II Summary and appendices D and E. Scour depths and recommended rock rip-rap sizes were computed using the general guidelines described in Hydraulic Engineering Circular 18 (Richardson and Davis, 1995) for the 100- and 500-year discharges. Total scour at a highway crossing is comprised of three components: 1) long-term streambed degradation; 2) contraction scour (due to accelerated flow caused by a reduction in flow area at a bridge) and; 3) local scour (caused by accelerated flow around piers and abutments). Total scour is the sum of the three components. Equations are available to compute depths for contraction and local scour and a summary of the results of these computations follows. Contraction scour for all modelled flows ranged from 0.7 to 2.1 ft. The worst-case contraction scour occurred at the 500-year discharge. Left abutment scour ranged from 6.8 to 8.4 ft. The worst-case left abutment scour occurred at the 500-year discharge. Right abutment scour ranged from 11.2 to 14.0 ft. The worst-case right abutment scour occurred at the 500-year discharge. Pier scour ranged from 12.9 to 19.3 ft. The worst-case pier scour occurred at the 500-year discharge. Additional information on scour depths and depths to armoring are included in the section titled “Scour Results”. Scoured-streambed elevations, based on the calculated scour depths, are presented in tables 1 and 2. A cross-section of the scour computed at the bridge is presented in figure 8. Scour depths were calculated assuming an infinite depth of erosive material and a homogeneous particle-size distribution. It is generally accepted that the Froehlich equation (abutment scour) gives “excessively conservative estimates of scour depths” (Richardson and Davis, 1995, p. 46). Usually, computed scour depths are evaluated in combination with other information including (but not limited to) historical performance during flood events, the geomorphic stability assessment, existing scour protection measures, and the results of the hydraulic analyses. Therefore, scour depths adopted by VTAOT may differ from the computed values documented herein.

Vermont↗
USGS1988

Demographic Characteristics of a Maine Woodcock Population and Effects of Habitat Management

A population of American woodcock (Scolopax minor) was studied on a 3,401-ha area of the Moosehorn National Wildlife Refuge in northeastern Maine from 1976 through 1985. During 1976-83, from 4 to 64 clearcuts were created each year, opening up large contiguous blocks of forest. A combination of mist nets, ground traps, nightlighting techniques, and trained dogs were used to capture and band 1,884 birds during the first 5 years. Capture and recapture data (totaling 3,009 observations) were used with both demographically closed and open population models to estimate population size and, for open population models, summer survival. Flying young, especially young males, represented the greatest proportion of all captures; analysis showed that young males were more prone to capture than young females. Male courtship began about 24 March each year, usually when there was still snow in wooded areas. Males ~2 years old dominated singing grounds during April each year, but this situation changed and first-year males dominated singing grounds in May. Singing males shifted from older established singing grounds to new clearcuts soon after we initiated forest management. Many males were subdominant at singing grounds despite an abundance of unoccupied openings. Three hundred adult females were captured and, except for 1978, the majority were ~2 years old. The year in which female homing rate was lowest(1979) was preceded by the year with the largest number of l-year-old brood female captures and a summer drought. Summer survival of young was lowest in 1978 and was attributed to summer drought. The year 1979 had an abnormally cool and wet spring, and was the poorest for production of young. Capture ratios of young-to-adult females obtained by nightlighting could be used to predict production on our study area. Closed population model estimates did not seem to fit either young or adult data sets well. Instead, a partially open capture-recapture model that allowed death but no immigration seemed to fit best. Only the number of males in the population changed significantly during the study. An increase from 88 males in 1976 to 156 in 1980 was attributed to habitat management. Singingmale surveys on our area detected little change in the number of singing males, but our independent population estimates from mark-recapture data showed a larger total male population by 1980. Annual density estimates for all age and sex classes ranged from 19 to 25 birds/l00 ha. A hypothesis on the breeding system of the American woodcock is presented as well as a discussion of management implications, including the importance of creating high-quality habitat on private lands.

Fish and Wildlife Research↗
USGS2014

Predicting impacts of future human population growth and development on occupancy rates of forest-dependent birds

Forest loss and fragmentation are among the largest threats to forest-dwelling wildlife species today, and projected increases in human population growth are expected to increase these threats in the next century. We combined spatially-explicit growth models with wildlife distribution models to predict the effects of human development on 5 forest-dependent bird species in Vermont, New Hampshire, and Massachusetts, USA. We used single-species occupancy models to derive the probability of occupancy for each species across the study area in the years 2000 and 2050. Over half a million new housing units were predicted to be added to the landscape. The maximum change in housing density was nearly 30 houses per hectare; however, 30% of the towns in the study area were projected to add less than 1 housing unit per hectare. In the face of predicted human growth, the overall occupancy of each species decreased by as much as 38% (ranging from 19% to 38% declines in the worst-case scenario) in the year 2050. These declines were greater outside of protected areas than within protected lands. Ninety-seven percent of towns experienced some decline in species occupancy within their borders, highlighting the value of spatially-explicit models. The mean decrease in occupancy probability within towns ranged from 3% for hairy woodpecker to 8% for ovenbird and hermit thrush. Reductions in occupancy probability occurred on the perimeters of cities and towns where exurban development is predicted to increase in the study area. This spatial approach to wildlife planning provides data to evaluate trade-offs between development scenarios and forest-dependent wildlife species.

Biological Conservation↗
USGS2020

Low stand density moderates growth declines during hot droughts in semi-arid forests

Increasing heat and aridity in coming decades is expected to negatively impact tree growth and threaten forest sustainability in dry areas. Maintaining low stand density has the potential to mitigate the negative effects of increasingly severe droughts by minimizing competitive intensity. However, the direct impact of stand density on the growing environment (i.e. soil moisture), and the specific drought metrics that best quantify that environment, are not well explored for any forest ecosystem. We examined the relationship of varying stand density (i.e. basal area) on soil moisture and stand‐level growth in a long‐term (multi‐decadal), ponderosa pine Pinus ponderosa , forest management experiment. We accounted for the influence of stand‐level density on moisture availability by measuring and modelling soil moisture using an ecosystem water balance model. To quantify the growing environment, we developed metrics of ecological drought that integrate the influence of moisture availability in the soil with moisture demand by the atmosphere. We paired these results with stand‐level dendrochronological data, avoiding the potential bias introduced from individual tree‐based assessments, and used critical climate period analysis to identify the timing and duration of these drought metrics that most relate to forest growth. We found that stand‐level growth is highly responsive to the combination of high temperature and low soil moisture. Growth in all stands was negatively related to temperature and positively related to moisture availability, although the sensitivity of growth to those conditions varied among stand density treatments. Growth enhancement during cool years is greatest in low density stands. In addition, low density stands displayed substantially higher long‐term average growth than higher density stands and maintained higher growth even when temperatures were high. Growth in low density stands also increased more than higher density stands in response to greater long‐term moisture availability. Synthesis and applications . We quantified the influence of stand‐level density on the environmental conditions that determine tree growth and related forest growth to patterns of moisture supply and demand. Our drought metrics, and analytical approach for quantifying drought impacts on forest growth, are a novel approach for assessing forest vulnerability to drought under climate change. These results provide new perspective on the potential for density management to mitigate drought stress and maintain forest stand growth during and after drought events in water‐limited forests.

Arizona↗
USGS2008

Geohydrology of the Unconsolidated Valley-Fill Aquifer in the Meads Creek Valley, Schuyler and Steuben Counties, New York

The Meads Creek valley encompasses 70 square miles of predominantly forested uplands in the upper Susquehanna River drainage basin. The valley, which was listed as a Priority Waterbody by the New York State Department of Environmental Conservation in 2004, is prone to periodic flooding, mostly in its downstream end, where development is occurring most rapidly. Hydraulic characteristics of the unconsolidated valley-fill aquifer were evaluated, and seepage rates in losing and gaining tributaries were calculated or estimated, in an effort to delineate the aquifer geometry and identify the factors that contribute to flooding. Results indicated that (1) Meads Creek gained about 61 cubic feet of flow per second (about 6.0 cubic feet per second per mile of stream channel) from ground-water discharge and inflow from tributaries in its 10.2-mile reach between the northernmost and southernmost measurement sites; (2) major tributaries in the northern part of the valley are not significant sources of recharge to the aquifer; and (3) major tributaries in the central and southern part of the valley provide recharge to the aquifer. The ground-water portion of streamflow in Meads Creek (excluding tributary inflow) was 11.3 cubic feet per second (ft3/s) in the central part of the valley and 17.2 ft3/s in the southern part - a total of 28.5 ft3/s. Ground-water levels were measured in 29 wells finished in unconfined deposits for construction of a potentiometric-surface map to depict directions of ground-water flow within the valley. In general, ground water flows from the edges of the valley toward Meads Creek and ultimately discharges to it. The horizontal hydraulic gradient for the entire 12-mile-long aquifer averages about 30 feet per mile, whereas the gradient in the southern fourth of the valley averages about half that - about 17 feet per mile. A water budget for the aquifer indicated that 28 percent of recharge was derived from precipitation that falls on the aquifer, 32 percent was from losing reaches of tributaries, 38 percent was unchanneled flow from hillsides that slope toward the valley (this estimate includes runoff and shallow ground-water inflow from till and bedrock), and the remaining 2 percent was from deep ground-water inflow from till and bedrock to the sides and bottom of the aquifer. Nearly all (94 percent) of the water discharged from the aquifer is equivalent to the streamflow gain in Meads Creek; the remaining 6 percent discharges as deep outflow to unconsolidated deposits in the Cohocton River valley. Several characteristics of the Meads Creek valley may contribute to flooding in the downstream area: (1) the southward decrease in the ground-water gradient impedes the ability of the aquifer to transmit water southward and can cause water levels to rise, (2) a high water table, typically only 5 to 10 feet below land surface, results in little storage capacity to absorb water from large storms, (3) a downstream narrowing of the valley impedes the southward flow of ground water and can cause water levels to rapidly rise during periods of prolonged or heavy precipitation, and (4) the upland slopes (till-covered bedrock) produce rapid runoff that recharges the aquifer. The combined effect of these conditions limits the ability of the aquifer to transmit sudden, large increases in recharge from precipitation and thereby provides a high potential for flooding in the southern third of the valley.

Scientific Investigations Report↗
USGS2014

The 3D Elevation Program: summary for New York

Elevation data are essential to a broad range of applications, including forest resources management, wildlife and habitat management, national security, recreation, and many others. For the State of New York, elevation data are critical for coastal zone management, natural resources conservation, agriculture and precision farming, flood risk management, infrastructure and construction management, water supply and quality, and other business uses. Today, high-density light detection and ranging (lidar) data are the primary sources for deriving elevation models and other datasets. Federal, State, Tribal, and local agencies work in partnership to (1) replace data that are older and of lower quality and (2) provide coverage where publicly accessible data do not exist. A joint goal of State and Federal partners is to acquire consistent, statewide coverage to support existing and emerging applications enabled by lidar data. The National Enhanced Elevation Assessment evaluated multiple elevation data acquisition options to determine the optimal data quality and data replacement cycle relative to cost to meet the identified requirements of the user community. The evaluation demonstrated that lidar acquisition at quality level 2 for the conterminous United States and quality level 5 ifsar data for Alaska with a 6- to 10-year acquisition cycle provided the highest benefit/cost ratios. The 3D Elevation Program (3DEP) initiative selected an 8-year acquisition cycle for the respective quality levels. 3DEP, managed by the U.S. Geological Survey (USGS), the Office of Management and Budget Circular A&ndash;16 lead agency for terrestrial elevation data, responds to the growing need for high-quality topographic data and a wide range of other 3D representations of the Nation&rsquo;s natural and constructed features.

New York↗