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621 results for “diameter”
Tree stem diameter and height of Araucaria araucana, Nothofagus pumilio and Nothofagus dombeyi in mixed stands affected to different levels by anthropogenic disturbance in south-central Chile
<p><em><strong>Context: </strong></em>Around half of the <em>Araucaria-Nothofagus</em> forests in Chile are affected by anthropogenic disturbances such as logging, grazing, and seed harvesting, causing forest structure to become more heterogeneous. This can critically affect natural regeneration and stand development. It also challenges forest management and yield estimations, involving tree height predictions. The data allow to assess the impact of anthropogenic disturbances on forest structure and to identify optimal tree height models and calibration designs. Based on the data provided, a general workflow for this purpose was developed and published on GitHub as R software (Zhou & Zwanzig 2022).</p> <p><em><strong>Location: </strong></em>Mixed <em>Araucaria-Nothofagus</em> forests of the Andes Cordillera in the Araucaria Region in south-central Chile. Latitude, longitude and altitude of the plots is provided in the data table.</p> <p><em><strong>Taxon:</strong></em> Monkey Puzzle tree (<em>Araucaria araucana</em> (Molina) K.Koch), Lenga Beech (<em>Nothofagus pumilio</em> (Poepp. & Endl.) Krasser), Coigue (<em>Nothofagus dombeyi</em> (Mirb.) Oerst.)</p> <p><em><strong>Methods:</strong></em> A total of twelve stands were studied at four different sites and classified into four different intensities of anthropogenic disturbance depending on the intensity of the combined effects of logging, grazing and seed harvesting. In 25 to 36 plots per stand, horizontal point sampling measurements of stem diameter as well as of height of selected trees were carried out using a basal area factor of 4 m² per hectare. Diameter at breast height (DBH, in cm) was measured for all selected trees and total tree height (HT, in m) was measured for one-third of them using a Haga device.</p> <p>For ten of the plots, in which no trees were found by horizontal point sampling, 'NA' is entered for species and no values are given for DBH and HT in the data table.</p> <p><em><strong>Funding:</strong></em> The field data collection was funded through the project 016/2019 “Indicadores fenológicos y estructurales de alteración de hábitat en bosques de <em>Araucaria</em>”, being part of the Fondo de Investigación del Bosque Nativo (FIBN) of the Corporación Nacional Forestal (CONAF) and the Ministry of Agriculture of Chile.</p> <p><em><strong>Contributions:</strong></em> JH, PC and AP conceived the field study and acquired the funds; EK, JH, PC and AP performed the empirical observations; XZ, EK and MZ reviewed and processed the data collection for publication.</p>
Data from: Relating pupil diameter and blinking to cortical activity and hemodynamics across arousal states
<p>Arousal state affects neural activity and vascular dynamics in the cortex, with sleep associated with large changes in the local field potential (LFP) and increases in cortical blood flow. We investigated the relationship between pupil diameter and blink rate with neural activity and blood volume in the somatosensory cortex in male and female unanesthetized, head-fixed mice. We monitored these variables while the mice were awake, during periods of rapid eye movement (REM), and during non-rapid eye movement (NREM) sleep. Pupil diameter was smaller during sleep than in the awake state. Changes in pupil diameter were coherent with both gamma-band power and blood volume in the somatosensory cortex, but the strength and sign of this relationship varied with arousal state. We observed a strong negative correlation between pupil diameter and both gamma-band power and blood volume during periods of awake rest and NREM sleep, though the correlations between pupil diameter and these signals became positive during periods of alertness, active whisking, and REM. Blinking was associated with increases in arousal and decreases in blood volume when the mouse was asleep. Bilateral coherence in gamma-band power and in blood volume dropped following awake blinking, indicating a 'reset' of neural and vascular activity. Using only eye metrics (pupil diameter and eye motion), we could determine the mouse's arousal state ('Awake', 'NREM', 'REM') with greater than 90% accuracy with a 5-second resolution. There is a strong relationship between pupil diameter and hemodynamics signals in mice, reflecting the pronounced effects of arousal on cerebrovascular dynamics.</p>
Text-fig. 7. Ammonoids from the Mospyne Formation. a: Anthracoceratites sp., lateral view; specimen IGSU-4/3634. b, c: Cymoceras sp., lateral view (b), fragment of the suture line in a 42 mm diameter conch (c); specimen IGSU-4/573. d, e: Neodimorphoceratidae indet., lateral view (d), surface ornamentation on the flank (e); specimen IGSU-4/5350. Scale bars 10 mm. in Late Bashkirian Ammonoids From The Mospyne Formation Of The Donets Basin, Ukraine
Text-fig. 7. Ammonoids from the Mospyne Formation. a: Anthracoceratites sp., lateral view; specimen IGSU-4/3634. b, c: Cymoceras sp., lateral view (b), fragment of the suture line in a 42 mm diameter conch (c); specimen IGSU-4/573. d, e: Neodimorphoceratidae indet., lateral view (d), surface ornamentation on the flank (e); specimen IGSU-4/5350. Scale bars 10 mm.
Data from: Relating pupil diameter and blinking to cortical activity and hemodynamics across arousal states
Open the record for dataset details and reuse information.
Individual tree height and diameter measurements of Birch spp. in central Sweden (2005 - 2022)
The spacing trial in Skräddarbo was established in 1989 on former agricultural land, testing four square spacing configurations: 1.3 × 1.3 m, 1.5 × 1.5 m, 1.8 × 1.8 m, and 2.6 × 2.6 m. Each spacing treatment was replicated four times for both silver birch and downy birch, totaling 32 plots across approximately 1.2 hectares. Each plot was planted with 100 seedlings, with varying plot sizes based on spacing. Species were randomly assigned to pre-determined plot locations. Data collection began in 2005 and continued annually until 2022 (except 2021). The data includes individual tree height, diameter and living crown measurements. Diameter measurements were recorded cross-sectionally, using a digital caliper, whereas tree height and living crown measurements were done using a hypsometer (Haglöf Vertex Laser Geo). Additional variables include plot area, tree id numbers and other constant variables. The data package is complete with the last revision done by the author in 2022.
Height and diameter measurement of spruce in response to harvest: 1993 - 2002
To document possible soil nitrogen mosaics before timber harvesting on three Alaskan boreal forest sites, maps of the distribution of understory green and Sitka alder stems were made. Understory alders were regularly distributed throughout the northernmost site (Standard Creek), and very irregularly distributed at the southernmost site (Cooper Landing). There were no consistent relations between alder stem location and total soil nitrogen. In undisturbed forest, soils collected beneath alders tended to have more nitrogen than soils without alder, but after the sites were harvested, soil chemistry differed. To examine the interactions of alder (Alnus crispa (Ait.) Pursh and A. sitchensis (Reg.) Rydb.) and white spruce (Picea glauca (Moench) Voss) on secondary successional sites, mixed plantations of white spruce and alder were established after each site was harvested. Despite good survival, the planted alder grew poorly. There were no differences between nursery-grown alder seedlings and alder wildlings in either growth or survival. Though fifth-year survival and growth of white spruce were excellent on all sites, they were not related to either the pre-harvest distribution of naturally occurring alder or to alders planted in the mixed plantations. Locational information and site maps are provided to encourage future evaluation of these plantations.
Point-center quarter method black spruce heights, diameter, and location for 150 mature black spruce sites in interior Alaska
This data set contains stand density measurements using the point-center quarter method at 150 extensive black spruce sites in interior Alaska collected in the summers of 2000, 2001, 2002 across the interior of Alaska along the Taylor highway, Alaska highway, Parks highway, Elliot highway, Steese highway, and Dalton highway.
Data to estimate stand density and average basal diameter from unburned black spruce stands used in the effects of variations in post-fire organic layer thickness studies in the Delta Junction region, 1995-2003
This database contains data on basal diameter and distances from a center point to the trees sampled, which is used to estimate stand density in unburned black spruce plots used in an analysis of variations in the depths of surface organic layers found in burned and unburned black spruce stands, and the effects of variations in depth of burning on soil temperature and moisture, and organic layer carbon stocks. Data for the overall study were collected between 1995 and 2003 by Eric Kasischke (University of Maryland), Kathy O?Neill (Duke University), and Jill Johnstone (University of Alaska Fairbanks). Sites were located in burned black spruce stands within the perimeters of three recent fires (1987, 1994, and 1999), unburned black spruce stands adjacent to the burned stands, and within one black spruce stand that burned in 1956. The three fires were: (a) the 1987 Granite Creek fire located 15 km to the east of Delta Junction, Alaska USA, bordering the Alaska Highway on the North and Jarvis Creek on the south; the 1994 Hajdukovich Creek fire located 45 km southeast of Delta Junction Alaska, USA, bordering the Alaska Highway to the North and the Gerstle River to the West, and the 1999 Donnelly Flats fire, located 8 km south of Delta Junction, bordering Jarvis Creek to the east and the Richardson Highway on the west. Data that were collected and are in databases associated with this project include: (1) organic layer depths in burned stands; (2) organic layer depths in unburned stands; (3) basal diameters of overstory trees in unburned stands and distance measures that can be used to estimate stand density; (4) mineral soil temperature and moisture data in burned stands; (5) mineral soil temperature and moisture data in unburned stands; and (6) bulk density and percent carbon data from different organic layers in unburned stands.
Tree regeneration after fire: Delta 1994 burn surveys, data to develop allometric equations re. seedling height or diameter to dry biomass
Data for this study were collected in 2001 and 2002 by Jill Johnstone (University of Alaska Fairbanks) and Eric Kasischke (University of Maryland). Sites were located within the perimeter of the 1994 burn southeast of Delta Junction Alaska, USA, bordering the Alaska Highway to the North and the Gerstle River to the West. Sites were selected from satellite classifications prepared by Eric Kasischke to represent different levels of burn severity and post-fire vegetation canopy greenness (NDVI). Site selection was constrained by road access, and only areas where all trees had been killed by the fire were selected. At each site, a central point was located in an area of visually homogeneous vegetation. Five parallel transects, each 50 m long, were laid out as follows: 1) the first transect started at the central point and followed a randomly-selected compass direction, 2) two additional transects were established parallel to the first, but at a random distance from the central transect up to 25 m distant. Vegetation was sampled in a 2-m wide belt centered on each transect, and soil samples were made at intervals along the transect line. Vegetation measurements included: a) basal diameters of all pre-fire trees greater than 1.3 m in height, b) counts of all post-fire tree seedlings, and c) basal diameters of tree seedlings and willows, measured in a randomly chosen 5x2 m portion of each transect. General notes were made on visual percent cover of different vegetation growth forms at the site. Destructive measurements of tree seedlings and willows made in 2001 were used to develop allometric equations to predict dry biomass from basal diameter. Measurements of soil organic layer depth were made at 5 m intervals with the use of a spade to excavate small chunks of sod. At one randomly-selected sample point per transect, a 10x10 cm sample of the organic layer was collected for bulk density measurements. Bulk density samples were dried in a 60degC oven for 48 hours and then w
Copulatory ducts curved or s-shaped, longer than diameter of spermathecae (10a) in A revision of the African wolf spider genus Amblyothele Simon
Copulatory ducts curved or s-shaped, longer than diameter of spermathecae (10a)
Copulatory ducts straight, shorter than diameter of spermathecae (9d) in A revision of the African wolf spider genus Amblyothele Simon
Copulatory ducts straight, shorter than diameter of spermathecae (9d)
Fitness measures of maternal transplants (seed fitness) and of the F1 generation (rosette diameter) of three translocated populations of Arnica montana in southern Belgium
<p>Fitness data measured in the framework of a genetic monitoring of translocated populations of the critically endangered Arnica montana. See Van Rossum et al. (2020) in Molecular Ecology for more details.</p>
Multiple abiotic and biotic drivers of long-term wood decomposition within and among species in semiarid inland dunes: a dual role for stem diameter
<p>This is wood decomposition data conducted in an semiarid inland dune including mass loss, initial wood traits and k values of combinations between five diameter classes and four shrub species under different treatments including UV and litter position. We found that after 34 months of in situ incubation, the mass loss of buried woody litters was three times faster than those of suspended and surface woody litters (53.5 ± 2.7 %, 17.0 ± 1.0 % and 14.4± 1.2 %, respectively). In surface and suspended positions, litter decomposition rates were almost equally low and most mass loss was during the first two years, when bark was still attached and UV radiation had no significant effect on woody litter mass loss.</p> <p> </p> <p> </p>
Figure 2. - Nesting architecture of Xylocopanasalis; Dissected nests of Xylocopanasalis revealing the nest structure inside the bamboo culm and its residents. Measurements of the nest parameters are shown in Table 1. The diameters of the nests (excluding the nest thickness) were measured at the nest entrance, followed by the vestibulum (antechamber) length, cell length, and the inner most cell length, respectively (2a). Cells containing larvae with pollen masses and their feces were collected and weighted (2b).
Figure 2. - Nesting architecture of Xylocopanasalis; Dissected nests of Xylocopanasalis revealing the nest structure inside the bamboo culm and its residents. Measurements of the nest parameters are shown in Table 1. The diameters of the nests (excluding the nest thickness) were measured at the nest entrance, followed by the vestibulum (antechamber) length, cell length, and the inner most cell length, respectively (2a). Cells containing larvae with pollen masses and their feces were collected and weighted (2b).
Sample video of 25 um diameter droplet sorting
<p>Sample video of 25 um diameter droplet sorting. </p>
Sample video of picoinjection into 20 um diameter droplets.
<p>Sample video of picoinjection into 20 um diameter droplets.</p>
Negative allometry of leaf xylem conduit diameter and double-wall thickness: implications for implosion safety
<p>Xylem conduits have lignified walls to resist crushing pressures. The thicker the double-wall (<em>T</em>) relative to its diameter (<em>D</em>), the greater the implosion safety. Having safer conduits may incur higher costs and reduced flow, while having less resistant xylem may lead to catastrophic collapse under drought. Although recent studies have shown that conduit implosion commonly occurs in leaves, little is known about how leaf xylem scales <em>T</em> versus <em>D</em> to trade off safety, flow efficiency, mechanical support, and cost.</p> <p>We measured <em>T</em> and <em>D</em> in > 7,000 conduits of 122 species to investigate how <em>T</em> versus <em>D</em> scaling varies across clades, habitats, growth forms, leaf and vein sizes.</p> <p>As conduits become wider, their double-cell walls become proportionally thinner, resulting in a negative allometry between <em>T</em> and <em>D</em>. That is, narrower conduits, which are usually subjected to more negative pressures, are proportionally safer than wider ones. Higher implosion safety (i.e higher <em>T/D</em> ratios) was found in asterids, arid habitats, shrubs, small leaves, and minor veins.</p> <p>Despite the strong allometry, implosion safety does not clearly trade off with other measured leaf functions, suggesting that implosion safety at whole-leaf level cannot be easily predicted solely by individual conduits' anatomy.</p>
Analysis of the root diameter distribution from time series images of real and simulated Cassava root systems
<p>The data was collected, simulated and analyzed in the framework of the CassavaStore project (a collaboration between IBG-2, Forschungszentrum Jülich, Germany and different institution from Thailand; for details see <a href="https://www.international-bioeconomy.org/cassavastore_eng">https://www.international-bioeconomy.org/cassavastore_eng</a>). Aim of this project is to get a better understanding of storage root development in cassava (<em>Manihot esculenta</em> Crantz) in order to optimize cassava growth with respect to variety breeding and growth management. The storage root is one of the main providers of starch in Thailand and therefore of high economic importance. Monitoring the formation of storage roots over time via quantification of the root diameter distribution of excavated root systems was one of the key aspects addressed in this project. To measure the diameters a software was developed that identifies roots in RGB images and analyzes the diameters along each identified root automatically. The published data contains 1) analyzed images from cassava roots that were acquired in a video box; 2) simulated virtual root model images with known root diameter distributions that were used to validate the analysis approach; 3) a description of the data and the folder structure.</p>
Drought timing and species growth phenology determine intra-annual recovery of tree height and diameter growth
<p>These are the data reported in van Kampen et al. (2022) "Drought timing and species growth phenology determine intra-annual recovery of tree height and diameter growth" published in AoB Plants. They describe patterns of height and diameter growth for saplings of six tree species undergoing experimental drought conditions at different times of year. </p>
Mycorrhizal colonization and root diameter of native and invasive plants of eastern North America
<p>Arbuscular mycorrhizal colonization (total and arbuscules) were measured in roots of 10 species of eastern North American woody plants. Five were non-native invasive and 5 were native species. Roots were collected from ingrowth cores over three harvests during a single season, from a common garden. Diameter was estimated from published root density and specific root length values for each species.</p>
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Allen Brain Atlas
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Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
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