Competitive responses of loblolly pine to gradients in loblolly pine, sweetgum, and broomsedge densities

1993 ◽  
Vol 23 (10) ◽  
pp. 2049-2058 ◽  
Author(s):  
M. A. Perry ◽  
R. J. Mitchell ◽  
B. R. Zutter ◽  
G. R. Glover ◽  
D. H. Gjerstad
Keyword(s):  
Organic Matter ◽  
Loblolly Pine ◽  
Intraspecific Competition ◽  
Polynomial Regression ◽  
Stem Volume ◽  
Regression Equations ◽  
Competitive Response ◽  
Crown Area ◽  
Seedling Size ◽  
Volume Response

A factorial combination of 0, 1, 2, and 4 loblolly pine (Pinustaeda L.) seedlings and sweetgum (Liquidambarstyraciflua L.) sprouts, and 0, 4, and 16 broomsedge (Andropogonvirginicus L.) seedlings per square metre were used to determine the nature of pine response to competition (competitive response) from multiple life forms during the first season after outplanting. Following adjustment for effects of seedling size and site heterogeneity (soil organic matter), polynomial regression was used to describe pine competitive responses. Patterns in competitive responses varied with time and were dependent upon the particular response variable of interest. Pine response in terms of volume was similar to that for diameter. By early May, pine diameter decreased linearly with increasing sweetgum density but was unrelated to either broomsedge or pine density. Approximately 1 month later, pine diameter response to competition was more complex, being curvilinearly related to both sweetgum and broomsedge density, as well as their interaction. Intraspecific competition effects on diameter response were not detected until mid-September. Height response differed substantively from diameter or volume response. In general, height tended to be less responsive to interspecific competition, although intraspecific competition was more readily detected. Furthermore, pine height response to competition tended to be linear rather than curvilinear, as observed for both diameter and volume. The biologically based reciprocal yield equation produced similar trends in competitive pine volume response, as noted with the polynomial regression equations (i.e., sweetgum and broomsedge density as well as their interaction strongly influenced the inverse of pine stem volume). Removing variation in organic matter and initial seedling size resulted in a considerable increase in the amount of variation in final size accounted for by competition. The reciprocal yield equation was also used with crown area rather than density to account for size differences among competitors. Analyzed in this manner, only main effects of sweetgum and broomsedge significantly influenced reciprocal yield; however, considerably less variation in response was accounted for using crown area than using density.

Synergistic stem volume response to combinations of vegetation control and seedling size in conifer plantations in Oregon

2006 ◽  
Vol 36 (4) ◽  
pp. 930-944 ◽  
Author(s):  
Lee S Rosner ◽  
Robin Rose
Keyword(s):  
Weed Control ◽  
Pacific Northwest ◽  
Analysis Of Covariance ◽  
Stem Volume ◽  
Conifer Species ◽  
Basal Diameter ◽  
Vegetation Control ◽  
Seedling Size ◽  
Volume Response ◽  
Stock Types

There are few published studies examining the effects of the interaction of seedling size and vegetation control on the growth of Pacific Northwest conifer species. Data from two vegetation management studies encompassing five planting sites, four conifer species, and two stock types were analyzed to determine the relative effects of seedling size at planting and intensity of vegetation control on subsequent seedling growth. Study 1 tested eight combinations of annual broadcast weed control or no weed control applied over the course of 5 years. Study 2 tested spot herbicide applications of differing area, as well as herbaceous-only and woody-only control treatments. The effect of seedling size was determined by analysis of covariance, with basal diameter as the covariate. Both seedling size and weed control increased growth of all conifer species through 4, 5, or 12 years, but responses varied by species and site. Diameter and height responses to weed control and seedling size were additive, whereas volume differences between treatments increased with increasing seedling size. The implication for management is that the volume return from increased weed control is maximized by planting the largest possible seedlings; conversely, the volume from increased seedling size is maximized at the highest weed control intensities.

PSVI-8 Meta-regression Analysis to Determine the Relationship Between Growing Pig Body Weight and Variation

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 218-219
Author(s):  
Andres Fernando T Russi ◽  
Mike D Tokach ◽  
Jason C Woodworth ◽  
Joel M DeRouchey ◽  
Robert D Goodband ◽  
...  
Keyword(s):  
Body Weight ◽  
Regression Analysis ◽  
Sample Size ◽  
Polynomial Regression ◽  
Data Sets ◽  
Regression Equations ◽  
Prediction Equations ◽  
Data Set ◽  
Rate Of Increase ◽  
The Relationship

Abstract The swine industry has been constantly evolving to select animals with improved performance traits and to minimize variation in body weight (BW) in order to meet packer specifications. Therefore, understanding variation presents an opportunity for producers to find strategies that could help reduce, manage, or deal with variation of pigs in a barn. A systematic review and meta-analysis was conducted by collecting data from multiple studies and available data sets in order to develop prediction equations for coefficient of variation (CV) and standard deviation (SD) as a function of BW. Information regarding BW variation from 16 papers was recorded to provide approximately 204 data points. Together, these data included 117,268 individually weighed pigs with a sample size that ranged from 104 to 4,108 pigs. A random-effects model with study used as a random effect was developed. Observations were weighted using sample size as an estimate for precision on the analysis, where larger data sets accounted for increased accuracy in the model. Regression equations were developed using the nlme package of R to determine the relationship between BW and its variation. Polynomial regression analysis was conducted separately for each variation measurement. When CV was reported in the data set, SD was calculated and vice versa. The resulting prediction equations were: CV (%) = 20.04 – 0.135 × (BW) + 0.00043 × (BW)2, R2=0.79; SD = 0.41 + 0.150 × (BW) - 0.00041 × (BW)2, R2 = 0.95. These equations suggest that there is evidence for a decreasing quadratic relationship between mean CV of a population and BW of pigs whereby the rate of decrease is smaller as mean pig BW increases from birth to market. Conversely, the rate of increase of SD of a population of pigs is smaller as mean pig BW increases from birth to market.

scholarly journals Influence of frying parameters and optimization of deep fat frying conditions on the physicochemical and textural properties of chicken nuggets from FUNAAB-Alpha broilers

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
O. R. Faloye ◽  
O. P. Sobukola ◽  
T. A. Shittu ◽  
H. A. Bakare
Keyword(s):  
Polynomial Regression ◽  
Textural Properties ◽  
Quality Attributes ◽  
Sample Thickness ◽  
Regression Equations ◽  
Deep Fat Frying ◽  
Chicken Nuggets ◽  
Frying Temperature ◽  
Frying Time ◽  
Standard Procedures

Abstract Influence of deep fat frying parameters on quality attributes of chicken nuggets from FUNAAB-Alpha broilers and optimization of the process using Box-Behnken experimental design of response surface methodology was investigated. Fried chicken nuggets were obtained using frying temperature (155–175 °C), frying time (3–7 min) and sample thickness (0.5–2.5 cm) as independent variables. Oil and moisture contents, texture (hardness, chewiness, adhesiveness, cohesiveness and springiness) and colour (L*, a* and b*) of samples were analyzed using standard procedures. Significance of each term in polynomial regression equations was evaluated on quality attributes. The accuracy of the regression models varied between 0.727 and 0.939. The effect of frying temperature on quality attributes of fried chicken nuggets was more significant (p > 0.05). The optimum frying temperature, frying time and sample thickness are determined as 175 °C, 3 min, 2.32 cm, respectively. Absolute percent error between optimized and experimental data were within the acceptable limit. Graphic abstract

Estimating Pinus palustris tree diameter and stem volume from tree height, crown area and stand-level parameters

2014 ◽  
Vol 25 (1) ◽  
pp. 43-52 ◽  
Author(s):  
C. A. Gonzalez-Benecke ◽  
Salvador A. Gezan ◽  
Lisa J. Samuelson ◽  
Wendell P. Cropper ◽  
Daniel J. Leduc ◽  
...  
Keyword(s):  
Pinus Palustris ◽  
Tree Height ◽  
Stem Volume ◽  
Crown Area ◽  
Tree Diameter

scholarly journals The Use of the Dynamics of Changes in Table Eggs during Storage to Predict the Age of Eggs Based on Selected Quality Traits

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3192
Author(s):  
Kamil Drabik ◽  
Tomasz Próchniak ◽  
Kornel Kasperek ◽  
Justyna Batkowska
Keyword(s):  
Polynomial Regression ◽  
Egg Quality ◽  
Model Fitting ◽  
Multiple Linear Regression Model ◽  
Specific Weight ◽  
Quality Parameters ◽  
Regression Equations ◽  
Mathematical Methods ◽  
Cage System ◽  
Daily Changes

The aim of the study was to determine daily changes in some egg quality parameters, indirectly reflecting egg freshness, and to assess the possibility of predicting time from laying using mathematical methods. The study material consisted of 365 table eggs of medium (M, ≥53 g and <63 g) and large (L, ≥63 g and <73 g) weight classes (commercial stock, cage system, brown-shelled eggs) collected on the same day. Eggs were numbered individually and placed on transport trays and stored (14 °C, 70% RH). Every day, for 35 days, egg quality characteristics were analyzed (10 eggs per group). The change of traits in time was analyzed on the basis of linear and polynomial regression equations, depending on the trait. Based on model fitting, eight traits were selected as those most affected by storage time: egg weight and specific weight, Haugh units, albumen weight, air cell depth, yolk index, albumen and yolk pH. These traits, excluding those related to the weight, were then used in a multiple linear regression model to predict egg age. All regression models presented in this study were characterized by high predictive efficiency, which was confirmed by comparison of the observed and estimated values.

Cubic-Foot Volume of Loblolly Pine to Any Merchantable Top Limit

1977 ◽  
Vol 1 (2) ◽  
pp. 7-9 ◽  
Author(s):  
Harold E. Burkhart
Keyword(s):  
Loblolly Pine ◽  
Stem Volume ◽  
Simple Equations ◽  
Volume Estimates ◽  
Volume Equations

Abstract Foresters commonly wish to predict tree volume for various top diameters. However, tree volume equations are generally restricted to specific top limits. Further, volume equations for various top limits often cross illogically. This study was conducted with the objective of developing logically related cubic-foot volume estimates for any desired top diameter limit. The approach taken was to predict total stem volume and to convert total volume to merchantable volumes by applying predicted ratios. Results reported here enable users to employ relatively simple equations to obtain cubic-foot volume to any top diameter limit. Volume between any two specified diameters on the stem can be obtained by subtraction.

Cubic-Foot Volume of Loblolly Pine to Any Height Limit

1980 ◽  
Vol 4 (4) ◽  
pp. 166-168 ◽  
Author(s):  
Quang V. Cao ◽  
Harold E. Burkhart
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Stem Volume ◽  
Pinus Taeda L

Abstract Flexible methods for computing the contents of various portions of tree boles are necessary with today's changing utilization standards. Equations are presented for estimating the cubic-foot volume of loblolly pine (Pinus taeda L.) trees to any desired height. The procedure involves predicting total stem volume and converting total volume to merchantable volume.

scholarly journals Rates of nitrogen from nitric and ammoniacal sources required by upland rice genotypes originating from Brazil and Colombia

2016 ◽  
Vol 37 (3) ◽  
pp. 1267 ◽  
Author(s):  
Hector Augusto Sandoval Contreras ◽  
Mario Sandoval Contreras ◽  
Renan Ribeiro Barzan ◽  
João Pedro Silvestre ◽  
Osmar Rodrigues Brito
Keyword(s):  
Polynomial Regression ◽  
Upland Rice ◽  
N Uptake ◽  
Calcium Nitrate ◽  
Dry Mass ◽  
Initial Growth ◽  
Regression Equations ◽  
Agronomic Efficiency ◽  
Mean Values ◽  
N Rates

The aim of this study was to evaluate the initial growth, nitrogen (N) uptake, and agronomic efficiency after the use of N fertilizers in upland rice cultivation. The experiment was conducted in a greenhouse by using pots filled with surface-layer (0 to 20 cm) soil collected from the municipality of Jaguapitã, Paraná. The experimental design was completely randomized with 4 replications. A factorial scheme of 5 × 2 was used, in which the factors were 5 N rates (0, 25, 50, 75, and 100 kg ha-1 N) and 2 cultivars of rice (Fedearroz Lagunas [Colombian] and IAPAR- 9 [Brazilian]). The N sources tested were ammonium sulfate (Experiment I) and calcium nitrate (Experiment II). The following variables were evaluated: number of tillers per pot (NTP), dry mass of the shoots (DMS), N content in the dry mass (NCDM), and agronomic efficiency of N fertilizer (AEN). The data obtained in the experiments were evaluated using analysis of variance, and mean values were compared using Tukey’s test at 5% significance for rice cultivar effects or adjusted to polynomial regression equations for N rates. Use of calcium nitrate yielded higher values of NTP, NCDM, and AEN. The cultivar Lagunas showed higher NTP, while IAPAR-9 showed higher DMS. An increase in N rates, for both sources, resulted in the increase of NTP, DMS, and NCDM; however, AEN was decreased.

Early Results from an Old-Field Loblolly Pine Spacing Study in the Georgia Piedmont with Competition Control

1993 ◽  
Vol 17 (4) ◽  
pp. 193-196 ◽  
Author(s):  
L. V. Pienaar ◽  
B. D. Shiver
Keyword(s):  
Loblolly Pine ◽  
Basal Area ◽  
Planting Density ◽  
Yield Potential ◽  
Stem Volume ◽  
Annual Increment ◽  
Average Growth ◽  
Vegetation Control ◽  
Early Results ◽  
Georgia Piedmont

Abstract The study reported here provides information on the yield potential of improved loblolly pine seedlings planted on marginal agricultural cropland in the Georgia Piedmont with control of herbaceous competition. Early growth rates greatly exceed those in existing plantations established on cutover and mechanically site-prepared land in this region without additional control of competing vegetation. After 8 growing seasons, average tree height, average dbh, basal area per acre, and stem volume per acre were all influenced by planting density, but the mean annual increment of merchantable volume (trees 4.0 in. dbh and bigger to a 2.0 in. top diameter) at age 8 yr, for planting densities of 400 to 1000 trees/ac, was 230 ft³, or approximately 3 cords/ac/yr. This is more than twice the average growth rate in this region of cutover and mechanically site-prepared loblolly plantations without additional vegetation control. These results should be of particular interest to prospective participants in the Conservation Reserve Program (CRP). South. J. Appl. For. 17(4):193-196.

scholarly journals The Effect of Physiographic Region and Geographic Locale on Predicting the Dominant Height and Basal Area of Loblolly Pine Plantations

2006 ◽  
Vol 30 (3) ◽  
pp. 147-153 ◽  
Author(s):  
Ralph L. Amateis ◽  
Stephen P. Prisley ◽  
Harold E. Burkhart ◽  
Jiping Liu
Keyword(s):  
Loblolly Pine ◽  
Geographic Location ◽  
Basal Area ◽  
Atlantic Coastal Plain ◽  
Regression Equations ◽  
Dominant Height ◽  
Northern Latitudes ◽  
Intensively Managed ◽  
Highly Correlated ◽  
Atlantic Coastal

Abstract Analysis of loblolly pine plantation permanent plot data established across the southeastern United States indicates that differences in dominant height and stand basal area may be related to geographic locale as well as physiographic region. In general, holding other factors constant,plantations at southern latitudes and eastern longitudes have less basal area than plantations at northern latitudes and western longitudes. Plantations at southern latitudes and eastern longitudes in the Atlantic Coastal Plain are generally taller than elsewhere in the Atlantic Coastal Plain.These trends were consistent for a younger population of intensively managed plantations, as well as for an older population of nonintensively managed plantations. Regression equations were developed to test the significance of geographic location on the prediction of basal area and dominantheight. Even in the presence of stand variables that are highly correlated with basal area and dominant height, latitude and longitude were highly significant predictors. Including them as predictor variables increased considerably the precision of the regression equations. South. J. Appl.For. 30(3):142–146.

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