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38 results for “snags”
Snag-fall patterns following stand-replacing fire vary with stem characteristics and topography in subalpine forests of Greater Yellowstone
We assessed the stem- and landscape-level drivers of snag persistence and snag-fall mode within the area burned as stand-replacing fire in the 1988 Yellowstone Fires in Yellowstone National Park, Wyoming, USA. Snags were sampled 14-15 years postfire (n = 131) and again in a separate set of plots 34 years postfire (n = 55). Stem characteristics such as species identity (e.g., lodgepole pine, whitebark pine, Engelmann spruce, subalpine fir, and Douglas-fir), diameter at breast height, whether the tree was alive or dead at the time of fire, and the mode of snag-fall (snapping or uprooting) were measured and used to explain patterns of snag persistence and modes of snag-fall. In addition, plot-level environmental variables (e.g., slope, aspect, elevation, stand density) were measured and related to the proportion of stems still standing as snags at 14-15 and 34 years postfire. Data collection is complete and is part of a forthcoming manuscript in revision at Forest Ecology and Management.
Dimensions, cover, volumes, mass and nutrient stores of Coarse Woody Debris (bark and wood from logs, snags, and stumps) from forests plots in the western United States and Mexico, 1977 to 2005
These data provide an inventory of the mass and nutrients stored within various forest types by coarse woody debris (CWD). CWD inventoried includes standing dead trees (greater than 10 cm diameter at breast height) and dead and downed wood (greater than 10 cm large end and >1 long). The majority of measurements are from permanent sample plots associated with the Andrews LTER permanent sample plots network. This includes clusters of plots at and near the H. J. Andrews Experimental Forest (OR), Cascade Head Experimental Forest (OR), Mount Rainier National Park (WA), Olympic National Park (WA), and Fraser Experimental Forest (CO). There are also data from plots in the Yucatan in Mexico; however, the live tree data for these plots is not available. The species of CWD inventoried are primarily those found in the Pacific Northwest; the dominants being Douglas-fir, western hemlock, mountain hemlock, western redcedar, Pacific silver fir, noblel fir, lodgepole pine, ponderosa pine, sitka spruce, and Englemann spruce. The majority of measurements were made in the 1975 to 1995 period; however plots are periodically remeasured and the intent to eventually remeasure all the plots except those in Mexico. In each plot measurements of log and snag dimensions (length and diameters), as well as decay class and species were recorded in the stands (td01201 file). These dimension data are combined with data on density and nutrient content for each species and decay class (td01202 file) and plot area and slope (td01203 file) to calculate CWD volume, cover, biomass and nutrient storage (td01204 file). When data on density and nutrient concentrations is not known, a list of substitutions is used (td01206). The adjust tree diameters if measurements are taken at the base of the dead tree, taper regressions are used (td01205).
Snag size and composition across a compositional gradient of intermediate-aged and mature forest stands within Interior Alaska collected 2008-2011.
This dataset includes snag biomass data for intermediate-aged and mature boreal forest stands across interior Alaska.
Far northeastern Siberia boreal forest data: Larch tree snag (dead tree) size distribution across a density gradient
This dataset includes basal diameter (bd) or diameter at breast height (DBH) of dead larch trees (snags) within four stands near Cherskii, Siberia. Data have not been published.
Data from: Evaluating the use of lidar to discern snag characteristics important for wildlife
<p>Standing dead trees (known as snags) are historically difficult to map and model using airborne laser scanning (ALS), or lidar. Specific snag characteristics are important for wildlife; for instance, a larger snag with a broken top can serve as a nesting platform for raptors. The objective of this study was to evaluate whether characteristics such as top intactness could be inferred from discrete-return ALS data. We collected structural information for 198 snags in closed-canopy conifer forest plots in Idaho. We selected 13 lidar metrics within 5 m diameter point clouds to serve as predictor variables in random forest (RF) models to classify snags into four groups by size (small [<40 cm diameter] or large [≥40 cm diameter]) and intactness (intact or broken top) across multiple iterations. We conducted these models first with all snags combined, and then ran the same models with only small or large snags. Overall accuracies were highest in RF models with large snags only (77%), but kappa statistics for all models were low (0.29–0.49). ALS data alone were not sufficient to identify top intactness for large snags; future studies combining ALS data with other remotely sensed data to improve classification of snag characteristics important for wildlife is encouraged.</p>
Data from: Drivers of snag fall rates in Fennoscandian boreal forests
<p>Persistence of standing dead trees (snags) is an important determinant for their role for biodiversity and dead wood associated carbon fluxes. How fast snags fall varies widely among species and regions and is further influenced by a variety of stand- and tree-level factors. However, our understanding of this variation is fragmentary at best, partly due to lack of empirical data. Here, we took advantage of the accruing time series of snag observations in the Finnish, Norwegian, and Swedish National Forest Inventories that have been followed in these programs since the mid-1990s. We first harmonized observations from slightly different inventory protocols and then, using this harmonized dataset of ca. 43 000 observations that had a consistent 5-year census interval, we modeled the probability of snags of the main boreal tree species <em>Pinus sylvestris</em>, <em>Picea abies</em>, and <em>Betula</em> spp. falling, as a function of tree- and stand-level variables, using Bayesian logistic regression modeling. The models were moderately good at predicting snags remaining standing or falling, with a correct classification rate ranging from 68% to 75% among species. In general, snag persistence increased with tree size and climatic wetness, and decreased with temperature sum, advancing stage of decay, site productivity, and disturbance intensity (mainly harvesting).</p> <p><em>Synthesis and applications.</em> The effect of harvesting demonstrates that an efficient avenue to increase the amount of snags in managed forests is protecting them during silvicultural operations. In the warmer future, negative relationship between snag persistence and temperature suggests decreasing the time snags remain standing and hence decreasing habitat availability for associated species. As decomposition rates generally increase after fall, decreasing snag persistence also implies substantially faster release of carbon from dead wood.</p>
Data for: Characterizing individual tree-level snags using airborne lidar-derived forest canopy gaps within closed-canopy conifer forests
<p><span>1. Airborne lidar is often used to calculate forest metrics about trees but it may also provide a wealth of information about the space between trees. Forest canopy gaps are defined by the absence of vegetative structure and serve important roles for wildlife, such as facilitating animal movement. Forest canopy gaps also occur around snags, keystone structures that provide important substrates to wildlife species for breeding, roosting, and foraging.</span></p> <p><span>2. We wanted to test a method for quantifying canopy gaps around individual snags and live trees, with the working hypothesis that snags would have more gaps surrounding them overall than live trees. We evaluated canopy gaps around individual snags (n=270) and live trees (n=2186) and evaluated correlations between canopy structure and snag occurrence in dense conifer stands of the Idaho Panhandle National Forest, USA. We paired airborne lidar with ground reference data collected at fixed-radius plots (n=53) to evaluate local gap structure. The R package ForestGapR was used to quantify canopy gaps throughout the canopy to determine where the differences were greatest. A canopy space profile was created for each tree by mapping gaps (a) vertically every 2 m in height (2–50 m above ground), and (b) horizontally across small (16 m<sup>2</sup>), medium (36 m<sup>2</sup>), and large (64 m<sup>2</sup>) footprint sizes.</span></p> <p><span>3. Our results suggest this method is robust for quantifying canopy gaps around individual trees. The canopy space profiles were distinctly different for snags and live trees, with more canopy gaps within the area surrounding snags relative to live trees. The greatest differences occurred at mid-canopy heights (~20 m above ground) and at the smallest footprint size (16 m<sup>2</sup>).</span></p> <p><span>4. These results show potential to improve understanding of gap dynamics in closed-canopy conifer forests, and we suggest snag modeling could be improved by incorporating lidar-derived canopy gap analyses alongside existing methodologies.</span></p>
Data from: Drivers of snag fall rates in Fennoscandian boreal forests
Open the record for dataset details and reuse information.
Data from: Evaluating the use of lidar to discern snag characteristics important for wildlife
Open the record for dataset details and reuse information.
Data for: Characterizing individual tree-level snags using airborne lidar-derived forest canopy gaps within closed-canopy conifer forests
Open the record for dataset details and reuse information.
A Randomized Placebo Controlled Trial on the Efficacy of Sustained Natural Apophyseal Glide (SNAG) in Low Back Pain Patients
ClinicalTrials.gov study NCT02128607. IPD Sharing: Not stated. Countries: 1. Publications: 4.
ELDOA Technique Versus Lumbar SNAGS With Motor Control Exercises
ClinicalTrials.gov study NCT06049251. IPD Sharing: NO. Countries: 1. Publications: 6.
Effects of Shi Style Cervical Mobilization Versus SNAGS in Patients With Cervicogenic Headache
ClinicalTrials.gov study NCT06459726. IPD Sharing: NO. Countries: 1. Publications: 5.
Comparing the Effects of Sub-Occipital Myofascial Release With and Without SNAG on People With Cervicogenic Dizziness.
ClinicalTrials.gov study NCT07062809. IPD Sharing: NO. Countries: 1. Publications: 9.
Cervical SNAG Half Rotation Technique in Cervicogenic Headache Patients.
ClinicalTrials.gov study NCT04788160. IPD Sharing: NO. Countries: 1. Publications: 9.
Thrust Joint Manipulation and Reverse SNAGS (Sustained Natural Apophyseal Glides) in Cervicogenic Headache
ClinicalTrials.gov study NCT04521218. IPD Sharing: NO. Countries: 1. Publications: 12.
Spinal Mobilization With Arm Movement and Positional SNAGS in Cervical Radiculopathy Patients
ClinicalTrials.gov study NCT05191537. IPD Sharing: NO. Countries: 1. Publications: 4.
Sustained Natural Apophysial Glides (SNAGs) Technique in Non-Specific Neck Pain Patients
ClinicalTrials.gov study NCT05425706. IPD Sharing: NO. Countries: 1. Publications: 2.
Mulligan SNAG Technique in Individuals With Lumbar Intervertebral Disc Protrusion
ClinicalTrials.gov study NCT06521294. IPD Sharing: NO. Countries: 1. Publications: 1.
Postural and Clinical Outcomes of SNAGs Treatment in Cervicogenic Dizziness Patients: a Randomised Controlled Trial
ClinicalTrials.gov study NCT04347148. IPD Sharing: NO. Countries: 1. Publications: 7.
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Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
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DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.