scholarly journals Crown-Diameter Prediction Models for 87 Species of Stand-Grown Trees in the Eastern United States

2003 ◽  
Vol 27 (4) ◽  
pp. 269-278 ◽  
Author(s):  
William A. Bechtold
Keyword(s):  
United States ◽  
Prediction Models ◽  
Basal Area ◽  
Stem Diameter ◽  
Quadratic Term ◽  
Eastern United States ◽  
Crown Diameter ◽  
Coefficients Of Variation ◽  
Bioclimatic Index ◽  
The Mean

Abstract The mean crown diameters of stand-grown trees were modeled as a function of stem diameter, live-crown ratio, stand basal area, latitude, longitude, elevation, and Hopkins bioclimatic index for 87 tree species in the eastern United States. Stem diameter was statistically significant in all models, and a quadratic term for stem diameter was required for some species. Crown ratio and/or Hopkins index also improved the models for many species. Coefficients of variation from the regression solutions ranged from 18 to 35%, and model r-square values ranged from 0.15 to 0.88. Simpler models, based only on stem diameter and crown ratio, are also presented. South. J. Appl. For. 27(4):269–278.

scholarly journals Largest-Crown-Width Prediction Models for 53 Species in the Western United States

2004 ◽  
Vol 19 (4) ◽  
pp. 245-251 ◽  
Author(s):  
William A. Bechtold
Keyword(s):  
United States ◽  
Prediction Models ◽  
Basal Area ◽  
Stem Diameter ◽  
Western United States ◽  
Quadratic Term ◽  
Crown Width ◽  
Coefficients Of Variation ◽  
Bioclimatic Index ◽  
Minor Improvement

Abstract The mean crown diameters of stand-grown trees 5.0-in. dbh and larger were modeled as a function of stem diameter, live-crown ratio, stand-level basal area, latitude, longitude, elevation, and Hopkins bioclimatic index for 53 tree species in the western United States. Stem diameter was statistically significant in all models, and a quadratic term for stem diameter was required for some species. Crown ratio and/or Hopkins index also improved the models for most species. A term for stand-level basal area was not generally needed but did yield some minor improvement for a few species. Coefficients of variation from the regression solutions ranged from 17 to 33%, and model R2 ranged from 0.15 to 0.85. Simpler models, based solely on stem diameter, are also presented. West. J. Appl. For. 19(4):245–251.

Habitat and estimated density of Magicicada septendecula (Hemiptera: Cicadidae), a 17-year periodical cicada newly discovered in Connecticut, United States of America

2014 ◽  
Vol 147 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Chris T. Maier
Keyword(s):  
United States ◽  
Sex Ratio ◽  
United States Of America ◽  
Basal Area ◽  
Eastern United States ◽  
Juglans Cinerea ◽  
Tibial Length ◽  
Periodical Cicadas ◽  
The Mean ◽  
Periodical Cicada

AbstractPeriodical cicadas in the genus Magicicada Davis (Hemiptera: Cicadidae) of brood II emerged in the eastern United States of America in 2013. In Connecticut, only Magicicada septendecim (Linnaeus) had been recorded until this emergence when Magicicada septendecula Alexander and Moore was found on Totoket Mountain in North Branford, Connecticut, United States of America. This discovery represented the northeastern-most record of this species. In two 0.25-ha plots where M. septendecula and M. septendecim emerged and chorused, species of Carya Nuttall (Juglandaceae) comprised 59.9–63.7% of the total basal area, with Carya glabra (Miller) Sweet, accounting for 43.9–60.0%. In one plot, 31.6% of the total basal area was Fraxinus americana Linnaeus (Oleaceae). By using the proportion of exuviae of M. septendecula (hind tibial length<6.3 mm) and M. septendecim (length ⩾ 6.3 mm) near trees and the mean number of emergence holes per 0.25-m2 quadrat (1.88), it was estimated that 1487 M. septendecula and 17 313 M. septendecim emerged in one 0.25-ha plot. Mean tibial length of M. septendecula was significantly smaller in males (5.53 mm) than females (5.99 mm), and the sex ratio did not depart significantly from 1:1. Magicicada septendecula may be threatened by the decline of F. americana and Juglans cinerea Linnaeus (Juglandaceae), the first a known host and the second a suspected host.

scholarly journals Evaluation of the U.S. Mothbean Collection for Seed Yield Potential in Virginia and Nutritional Composition of Freshly Harvested Seed

2016 ◽  
Vol 26 (6) ◽  
pp. 820-824
Author(s):  
Harbans L. Bhardwaj ◽  
Anwar A. Hamama
Keyword(s):  
United States ◽  
Nutritional Composition ◽  
Yield Potential ◽  
Eastern United States ◽  
Tepary Bean ◽  
Legume Crop ◽  
Iron And Zinc ◽  
The Mean ◽  
Calcium Iron ◽  
Seed Yields

Even though mothbean (Vigna aconitifolia), a drought- and heat-tolerant crop, may have potential in the eastern United States, information about its production in this region is not available. To characterize potential seed yields and preliminary nutritional quality, 54 accessions were grown near Petersburg, VA, during 2011, 2012, and 2013. The seed yields varied from 48 to 413 lb/acre. The mean concentrations of protein, calcium, iron, and zinc in mature mothbean seed were 21.9%, 0.17%, 64.8 ppm, and 37.5 ppm, respectively. These values compared well with those in mungbean (Vigna radiata) and tepary bean (Phaseolus acutifolius). The results demonstrated that mothbean has considerable potential as an alternative, new food legume crop in Virginia and eastern United States.

scholarly journals Multiple Treatment Meta-Analysis of Products Evaluated for Control of Fire Blight in the Eastern United States

2011 ◽  
Vol 101 (5) ◽  
pp. 512-522 ◽  
Author(s):  
H. K. Ngugi ◽  
B. L. Lehman ◽  
L. V. Madden
Keyword(s):  
United States ◽  
Biological Control ◽  
Disease Control ◽  
Plant Defense ◽  
Fire Blight ◽  
Pantoea Agglomerans ◽  
Effect Sizes ◽  
Eastern United States ◽  
The Mean ◽  
Prohexadione Calcium

The aim of this analysis was to estimate the effect sizes and consistency of products evaluated for fire blight control in the eastern United States over the last decade. Because only 3% of the 69 studies published from 2000 to 2008 explicitly presented a measure of within-study variability, a method for estimating the least significant difference (LSD) and, hence the sampling variance, for studies with at least two significant mean separations in the presented mean multiple comparisons was developed. Lin's concordance analysis indicated that the estimated LSD was an accurate predictor of the actual LSD based on 35 studies in a calibration evaluation (ρc = 0.997). Separate multi-treatment random-effects meta-analyses were performed for three control categories: antibiotics, biological control, and plant defense-activating products and mean log response ratios relative to the nontreated controls ([Formula: see text]) were computed for each treatment and then back-transformed to obtain the mean percent disease control. None of the products evaluated performed as well as streptomycin, the standard product for fire blight control, for which the mean disease control was 68.6%. As a group, experimental antibiotics provided the best fire blight control with mean effect sizes ranging from 59.7 to 61.7%. Among the biological controls, the best control was noted for treatments combining the antibiotic streptomycin with a product based on Pantoea agglomerans (55.0% mean disease reduction) or Bacillus subtilis (53.9%). Mean disease control was 31.9, 25.7, and 22.6%, respectively, for products based on B. subtilis, Pantoea agglomerans, and Pseudomonas fluorescens without an antibiotic, suggesting that the higher efficacy of the combination treatments was due to the antibiotic. Among the plant defense-activating products, prohexadione calcium had the highest and most consistent effect size (50.7% control), while other products provided modest mean disease control of between 6.1 and 25.8%. Percent control values were significantly moderated by study location and cultivar used in the study, and were smaller, but more variable, when products were tested under high disease intensity compared with low disease intensity. Results indicate that wide-scale use of biological control and plant defense-activating products in the eastern United States is likely to remain low.

scholarly journals Evaluation of Precipitation from Numerical Weather Prediction Models and Satellites Using Values Retrieved from Radars

2007 ◽  
Vol 135 (11) ◽  
pp. 3750-3766 ◽  
Author(s):  
Slavko Vasić ◽  
Charles A. Lin ◽  
Isztar Zawadzki ◽  
Olivier Bousquet ◽  
Diane Chaumont
Keyword(s):  
United States ◽  
Prediction Models ◽  
Weather Prediction ◽  
Decomposition Methods ◽  
Grid Size ◽  
Eastern United States ◽  
Model Resolution ◽  
Forecast Period ◽  
Statistical Measures ◽  
Numerical Weather Prediction Models

Abstract Precipitation is evaluated from two weather prediction models and satellites, taking radar-retrieved values as a reference. The domain is over the central and eastern United States, with hourly accumulated precipitation over 21 days for the models and radar, and 13 days for satellite. Conventional statistical measures and scale decomposition methods are used. The models generally underestimate strong precipitation and show nearly constant modest skill over a 24-h forecast period. The scale decomposition results show that the effective model resolution for precipitation is many times the grid size. The model predictability extends beyond a few hours for only the largest scales.

Modelling growing space requirement for Alnus nepalensis D. Don in Nepal

1970 ◽  
Vol 16 (2) ◽  
pp. 30-36 ◽  
Author(s):  
Ram Prasad Sharma
Keyword(s):  
Prediction Models ◽  
Growth Models ◽  
Basal Area ◽  
Individual Tree ◽  
Area Density ◽  
Space Requirement ◽  
Space Model ◽  
Alnus Nepalensis ◽  
Crown Diameter ◽  
Individual Trees

Relationship between crown diameter and stem diameter of individual trees can be translated into mathematical model, and used to generate information of growing space requirement for individual trees and crown competition index for growth models. Nine different crown diameter prediction models were developed using inventory data of Alnus nepalensis trees from a part of Parbat and Syanja districts in Nepal. Among those developed, a non-linear three parameter-based model (W = β0 {1 – exp( - β1D)}β2) explained the greatest proportion of variations of crown diameter (R2adj = 0.78), and showed desirable behaviour of flexibility and robustness. An individual tree growing space model was then derived from crown model to generate important information of shocking limits and stand basal area density for monoculture plantation or natural stands of Alnus nepalensis. Because of its flexibility, crown model is seemed potentially useful for extrapolation purpose also. However, the model cannot be applied for buttressed, wolfed and malformed trees. Key words: Alnus nepalensis; crown model; growing space model; stocking limit; basal area density Banko Janakari Vol.16(2) 2006 pp.30-36

Uncertainties, Trends, and Hottest and Coldest Years of U.S. Surface Air Temperature since 1895: An Update Based on the USHCN V2 TOB Data

2012 ◽  
Vol 25 (12) ◽  
pp. 4185-4203 ◽  
Author(s):  
Samuel S. P. Shen ◽  
Christine K. Lee ◽  
Jay Lawrimore
Keyword(s):  
United States ◽  
Air Temperature ◽  
Sampling Error ◽  
Linear Trend ◽  
Surface Air Temperature ◽  
The United States ◽  
Eastern United States ◽  
Monthly Data ◽  
Historical Climatology ◽  
The Mean

Abstract This paper estimates the sampling error variances of gridded monthly U.S. Historical Climatology Network, version 2 (USHCN V2), time-of-observation-biases (TOB)-adjusted data. The analysis of mean surface air temperature (SAT) assesses uncertainties, trends, and the rankings of the hottest and coldest years for the contiguous United States in the period of 1895–2008. Data from the USHCN stations are aggregated onto a 2.5° × 3.5° latitude–longitude grid by an arithmetic mean of the stations inside a grid box. The sampling error variances of the gridded monthly data are estimated for every month and every grid box with data. The gridded data and their sampling error variances are used to calculate the contiguous U.S. averages and their trends and associated uncertainties. The sampling error variances are smaller (mostly less than 0.2°C2) over the eastern United States, where the station density is greater and larger (with values of 1.3°C2 for some grid boxes in the earlier period) over mountain and coastal areas. In the period of 1895–2008, every month from January to December has a positive linear trend. February has the largest trend of 0.162°C (10 yr)−1, and September has the smallest trend at 0.020°C (10 yr)−1. The three hottest (coldest) years measured by the mean SAT over the United States were ranked as 1998, 2006, and 1934 (1917, 1895, and 1912).

Baldcypress height–diameter equations and their prediction confidence intervals

1992 ◽  
Vol 22 (9) ◽  
pp. 1429-1434 ◽  
Author(s):  
Bernard R. Parresol
Keyword(s):  
United States ◽  
Confidence Intervals ◽  
Nonlinear Regression ◽  
Basal Area ◽  
Confidence Bands ◽  
Bald Cypress ◽  
Prediction Confidence ◽  
Independent Variable ◽  
The Mean ◽  
Stand Basal Area

Height–diameter relationships are an important component in yield estimation, stand description, and damage appraisals. A nonlinear exponential function used extensively in the northwest United States was chosen for bald cypress (Taxodiumdistichum (L.) Rich.). Homogeneity and normality of residuals were examined, and the function as well as the mean and individual prediction confidence bands were plotted. The inclusion of stand basal area as an additional independent variable provided a better fit to the data. The paper is concluded with a section on construction and use of simple and joint confidence intervals about the mean and individual predictions from the nonlinear regression.

scholarly journals An Examination of Precipitation in Observations and Model Forecasts during NAME with Emphasis on the Diurnal Cycle

2007 ◽  
Vol 20 (9) ◽  
pp. 1680-1692 ◽  
Author(s):  
John E. Janowiak ◽  
Valery J. Dagostaro ◽  
Vernon E. Kousky ◽  
Robert J. Joyce
Keyword(s):  
United States ◽  
Diurnal Cycle ◽  
Prediction Models ◽  
Numerical Models ◽  
The United States ◽  
Rain Gauge ◽  
North American Monsoon ◽  
Eastern United States ◽  
Direct Evaluation ◽  
The North

Abstract Summertime rainfall over the United States and Mexico is examined and is compared with forecasts from operational numerical prediction models. In particular, the distribution of rainfall amounts is examined and the diurnal cycle of rainfall is investigated and compared with the model forecasts. This study focuses on a 35-day period (12 July–15 August 2004) that occurred amid the North American Monsoon Experiment (NAME) field campaign. Three-hour precipitation forecasts from the numerical models were validated against satellite-derived estimates of rainfall that were adjusted by daily rain gauge data to remove bias from the remotely sensed estimates. The model forecasts that are evaluated are for the 36–60-h period after the model initial run time so that the effects of updated observational data are reduced substantially and a more direct evaluation of the model precipitation parameterization can be accomplished. The main findings of this study show that the effective spatial resolution of the model-generated precipitation is considerably more coarse than the native model resolution. On a national scale, the models overforecast the frequency of rainfall events in the 1–75 mm day−1 range and underforecast heavy events (&gt;85 mm day−1). The models also have a diurnal cycle that peaks 3–6 h earlier than is observed over portions of the eastern United States and the NAME tier-1 region. Time series and harmonic analysis are used to identify where the models perform well and poorly in characterizing the amplitude and phase of the diurnal cycle of precipitation.

scholarly journals Prolonged Dry Episodes over the Conterminous United States: New Tendencies Emerging during the Last 40 Years

2008 ◽  
Vol 21 (9) ◽  
pp. 1850-1862 ◽  
Author(s):  
Pavel Ya Groisman ◽  
Richard W. Knight
Keyword(s):  
United States ◽  
Average Duration ◽  
Warm Season ◽  
Vegetation Period ◽  
Total Precipitation ◽  
Eastern United States ◽  
The Past ◽  
The Mean ◽  
Rain Events ◽  
Precipitation Events

Abstract A disproportionate increase in precipitation coming from intense rain events, in the situation of general warming (thus, an extension of the vegetation period with intensive transpiration), and an insignificant change in total precipitation could lead to an increase in the frequency of a potentially serious type of extreme events: prolonged periods without precipitation (even when the mean seasonal rainfall totals increase). This paper investigates whether this development is already occurring during the past several decades over the conterminous United States, for the same period when changes in frequency of intense precipitation events are being observed. Lengthy strings of “dry” days without sizeable (&gt;1.0 mm) precipitation were assessed only during the warm season (defined as a period when mean daily temperature is above the 5°C threshold) when water is intensively used for transpiration and prolonged periods without sizable rainfall represent a hazard for terrestrial ecosystem’s health and agriculture. During the past four decades, the mean duration of prolonged dry episodes (1 month or longer in the eastern United States and 2 months or longer in the southwestern United States) has significantly increased. As a consequence the return period of 1-month-long dry episodes over the eastern United States has reduced more than twofold from 15 to 6–7 yr. The longer average duration of dry episodes has occurred during a relatively wet period across the country but is not observed over the northwestern United States.

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