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 A High Resolution Spatiotemporal Fine Particulate Matter Exposure Assessment Model for the Contiguous United States

2021 ◽  
Author(s):  
Cole Brokamp
Keyword(s):  
United States ◽  
Particulate Matter ◽  
Exposure Assessment ◽  
Confidence Intervals ◽  
Fine Particulate Matter ◽  
Model Performance ◽  
Assessment Model ◽  
Fine Particulate ◽  
Prediction Confidence ◽  
Geographic Regions

Currently available nationwide prediction models for fine particulate matter (PM2.5) lack prediction confidence intervals and usually do not describe cross validated model performance at different spatiotemporal resolutions and extents. We used 41 different spatiotemporal predictors, including data on land use, meteorology, aerosol optical density, emissions, wildfires, population, traffic, and spatiotemporal indicators to train a machine learning model to predict daily averages of PM2.5 concentrations at 0.75 sq km resolution across the contiguous United States from 2000 through 2020. We utilized a generalized random forest model that allowed us to generate asymptotically-valid prediction confidence intervals and took advantage of its usefulness as an ensemble learner to quickly and cheaply characterize leave-one-location-out CV model performance for different temporal resolutions and geographic regions. Using a variable importance metric, we selected 8 predictors that were able to accurately predict daily PM2.5, with an overall leave-one-location-out cross validated median absolute error of 1.20 ug/m3, an R2 of 0.84, and confidence interval coverage fraction of 95%. When considering aggregated temporal windows, the model achieved leave-one-location-out cross validated median absolute errors of 0.99, 0.76, 0.63, and 0.60 ug/m3 for weekly, monthly, annual, and all-time exposure assessments, respectively. We further describe the model’s cross validated performance at different geographic regions in the United States, finding that it performs worse in the Western half of the country where there are less monitors. The code and data used to create this model are publicly available and we have developed software packages to be used for exposure assessment. This accurate exposure assessment model will be useful for epidemiologists seeking to study the health effects of PM across the continental United States, while possibly considering exposure estimation accuracy and uncertainty specific to the the spatiotemporal resolution and extent of their study design and population.

Estimating the Probability of Emigration from Individual-Specific Data: The Case of Italy in the Early Twentieth Century

1986 ◽  
Vol 20 (1) ◽  
pp. 69-80
Author(s):  
Thomas H. Mondschean
Keyword(s):  
United States ◽  
Twentieth Century ◽  
Confidence Intervals ◽  
Conditional Probability ◽  
Random Sample ◽  
Standard Error ◽  
The United States ◽  
Personal Attributes ◽  
Specific Data ◽  
The Mean

This article develops a method for estimating the probability of emigration conditional on the observed characteristics of individuals. In addition, it is shown how to calculate the mean, standard error, and confidence intervals of the conditional probability of emigration given a random sample of emigrants. The technique is illustrated by providing statistically consistent estimates of the probability an Italian would emigrate to the United States in 1901 and 1911, conditional on personal attributes.

scholarly journals Maximum Stand-Density Index of 40 Western Hemlock–Sitka Spruce Stands in Southeast Alaska

2007 ◽  
Vol 22 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Nathan J. Poage ◽  
David D. Marshall ◽  
Michael H. McClellan
Keyword(s):  
Basal Area ◽  
Stand Density ◽  
Site Factors ◽  
Southeast Alaska ◽  
Spruce Stands ◽  
The Mean ◽  
Stand Density Index ◽  
Over Time ◽  
Stand Basal Area ◽  
Species Proportion

Abstract Reineke's (1933) maximum stand-density index (SDImax) was determined for 40 unthinned, fully stocked, even-aged, hemlock-spruce stands in southeast Alaska. A nonlinear model was used to identify objectively the linear portions of the stands' self-thinning trajectories for analysis. The objectives of the present study were (1) to use the modeled slopes and intercepts to determine the mean SDImax of the stands and (2) to identify stand and site factors associated with the variability observed in SDImax. The mean SDImax of the 40 hemlock-spruce stands in southeast Alaska was 619. Individually, none of the stand or site factors examined accounted for >30% of the variability observed in SDImax when all 40 stands were analyzed together. Although the spruce proportion of total stand basal area of most stands increased over time and the hemlock proportion of total stand basal area of most stands decreased over time, SDImax was not related to species proportion or changes in species proportion over time.

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 Prediction and Error of Baldcypress Stem Volume from Stump Diameter

1998 ◽  
Vol 22 (2) ◽  
pp. 69-73 ◽  
Author(s):  
Bernard R. Parresol
Keyword(s):  
Confidence Intervals ◽  
Stem Volume ◽  
Volume Estimate ◽  
Logarithmic Model ◽  
Post Harvest ◽  
Independent Variable ◽  
The Mean ◽  
Stump Diameter

Abstract The need to estimate the volume of removals occurs for many reasons, such as in trespass cases, severance tax reports, and post-harvest assessments. A logarithmic model is presented for prediction of baldcypress total stem cubic foot volume using stump diameter as the independent variable. Because the error of prediction is as important as the volume estimate, I demonstrate construction and use of simple and joint confidence intervals about the mean and individual predictions. For completeness, I address prediction and error from inventory estimates of removals. South. J. Appl. For. 22(2):69-73.

Prediction of stand susceptibility and gypsy moth defoliation in Coastal Plain mixed pine–hardwoods

2001 ◽  
Vol 31 (11) ◽  
pp. 1914-1921
Author(s):  
C B Davidson ◽  
J E Johnson ◽  
K W Gottschalk ◽  
R L Amateis
Keyword(s):  
United States ◽  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Coastal Plain ◽  
Southeastern United States ◽  
Basal Area ◽  
Leading Edge ◽  
Threshold Level ◽  
The Relationship ◽  
Stand Basal Area

The European gypsy moth (Lymantria dispar L.) is an introduced defoliator that has become endemic in forests of the northeastern United States. During the last five decades, populations have continued to advance into the southeastern United States. Defoliation outbreaks continue to occur along the leading edge of the infestation, and the potential for extensive defoliation within southern forests remains. A field study was implemented in 1991 to determine the relationship between species composition and gypsy moth defoliation in Coastal Plain mixed pine–hardwood stands and to formulate a defoliation prediction model. Stands in both pine–oak and pine–sweetgum cover types were extensively defoliated during a single defoliation outbreak. Mean stand defoliation in the pine–oak type peaked at 42.6% in 1994, while mean defoliation in the pine–sweetgum type peaked at 32.8% in 1995. Defoliation intensity was significantly related to stand composition, with oaks and sweetgum being defoliated at the greatest intensities. Overall, pines were not heavily defoliated in either cover type. However, moderate to heavy defoliation of a small number of overstory pines was observed in some pine–oak stands and appeared to be due to a threshold level of oak defoliation (>80%). A nonlinear model for the prediction of mean total stand defoliation is also presented. Defoliation is predicted as a function of the number of gypsy moth egg masses, the number of years since the beginning of the outbreak, susceptible species basal area, pine basal area, and total stand basal area.

Above-ground phytomass of a tropical deciduous forest on the coast of Jalisco, México

1992 ◽  
Vol 8 (01) ◽  
pp. 87-96 ◽  
Author(s):  
Angelina Martinez-Yrizar ◽  
Jose Sarukhan ◽  
Alfredo Perez-Jimenez ◽  
Emmanuel Rincon ◽  
Jose Manuel Maass ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Deciduous Forest ◽  
Basal Area ◽  
Tree Height ◽  
Tropical Dry Forests ◽  
Stepwise Multiple Regression ◽  
Tropical Deciduous Forest ◽  
Stepwise Multiple Regression Analysis ◽  
Independent Variable ◽  
The Mean

ABSTRACTPhytomass was determined for a tropical deciduous forest in Chamela, Jalisco, México. The mean canopy height was 6.9 m, and the total basal area was 25.6 m2ha−1(dbh > 3.0 cm). The estimated phytomass for this forest (85 Mg ha−1) is among the highest values for tropical dry forests with similar seasonal climates. A stepwise multiple regression analysis showed that phytomass can be predicted firstly by basal area (R2= 0.88), then by wood specific gravity (R2= 0.91), and finally by the inclusion of tree height in the regression (R2= 0.92). Each new independent variable explained significant variance in the phytomass estimation.

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.

Live tree species basal area of the contiguous United States (2000-2009)

2013 ◽  
Author(s):  
Barry T. Wilson ◽  
Andrew J. Lister ◽  
Rachel I. Riemann ◽  
Douglas M. Griffith
Keyword(s):  
United States ◽  
Tree Species ◽  
Basal Area ◽  
Live Tree

POTRET PERILAKU RELIGIUS MAHASISWA UIN SAYARIF HIDAYATULLAH JAKARTA

Al-Risalah ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 126-148
Author(s):  
Ay Maryani
Keyword(s):  
Religious Behavior ◽  
Male And Female ◽  
Mean Values ◽  
Significance Level ◽  
Average Value ◽  
Environment Variable ◽  
Independent Variable ◽  
The Mean ◽  
Gender Factor ◽  
Level 2

This study describes the religious behavior of UIN Syarif Hidayatullah Jakarta students. The variables used are internal and external environment as independent variable and religious behavior as dependent variable. The internal environment variable consists of gender factor, (male and female). The external environmental variables comprise the faculty environment, the present resident and the place to grow. The present resident consist of dormitories, boarding houses and parents' homes and the place to grow consist of urban and rural environment. Religious behavior variables consist of habluminallah behavior and habluminannas behavior. Habluminallah's behavior measured by (1) knowledge of faith and worship, (2) attitudes toward faith and worship, and (3) practice of faith and worship. The habluminannas variable measured by (1) Islamic behavior for them self, like honest, discipline and good work / studyethics, trust and concern on legality, (2) Islamic behavior with others, like generous, cooperation, caring, respect to the people's rights and tolerance and (3) Islamic behavior for the natural surroundings, like love of nature and nature conservation efforts. The methodology used was (1) Statistical descriptive, (2) MANOVA (Multivariate Analysis of Variance) and (3) Independent sample t-test. The results showed the religious behavior UIN Syarif Hidayatullah Jakarta students has a very good category. This is indicated by the mean values for the behavior of haluminallah and habluminannas of 158.85 and 178.76,  espectively. The average value of habluminallah behaviour in the range of values "145-180" with the category of "very good" and habluminannas behavior in the range value "165-205" with the category "very good. Habluminallah and habluminannas behavior are different for each faculty. This is indicated by the significance level of Pillai Trace, Wilk Lambda, Hotelling Trace, Roy's Largest Root of 0.00 (<0.05). Habluminallah and habluminannas behavior are the same for respondents who live in dormitories, boarding houses, and parents' homes. This is indicated by the value of F test and significance at Wilk's Lambda respectively for 2.055 and 0.085 (>0.05). Habluminallah and habluminannas behaviors are similar for urban and rural respondents. This is known from the sig level. (2-tailed) for habluminallah and habluminannas behavior of 0.317 and 0.245 (> 0.05), respectively. Habluminallah and habluminannas behaviors are similar for male and female. This is known from the sig level. (2-tailed) for habluminallah and habluminannas behavior of 0.950 and 0.307 (> 0.05),respectively. The results of this study are expected to be used to develop university policies that can enhance the Islamic values of UIN Syarif Hidayatullah Jakarta.

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