Huber's Formula Research Articles

Модели для оценки биомассы и объема коры деревьев липы мелколистной (Tilia cordata Mill.)

The research is aimed at analyzing variability and developing mathematical models for estimating bark biomass and volume, volume of trunk with bark, and bark proportion of small-leaved linden (Tilia cordata Mill.) trees growing in natural coppice and artificial stands. The models are based on data from 107 and 95 destructively sampled trees in natural coppice and artificial stands, respectively. There were 10 sampling areas per stand type, representing different growth stages. The model trees were sawn into 2-meter sections, the volumes of which with and without bark were calculated using the Huber formula. The total volume of the tree trunk with and without bark is obtained by summing the volumes of all sections and the conical volume of the tree top. The bark volume was the difference between these two parameters. The bark biomass was determined by direct weighing, followed by conversion to absolutely dry mass. The correlations between the dendrometric parameters and the selected tree characteristics were estimated. The effectiveness of 3 regression models using the diameter at breast height (dbh = 1.3 m) and the tree height (h) as independent variables was studied in a comparative aspect. The bark biomass and volume, and the volume of trunk with bark are strongly influenced by these values. This correlation is very weak for the bark volume proportion in natural coppice stands, and insignificant in artificial stands. The bark volume proportion for each tree was calculated as the ratio of the difference between the volume of trunk with and without bark and the volume of trunk with bark. The equation that showed the best statistical characteristics in terms of consistency was chosen in order to predict the bark biomass and volume, the volume of trunks with bark of small-leaved linden trees. These models were estimated using the weighted least squares method taking into account the inherent errors and heteroscedasticity, by assigning each model its weight function separately for natural coppice and artificial stands that differ significantly from each other in morphometric features.

Estimating the tree bole volume of Brutian pine (Pinus brutia Ten.) and Taurus cedar (Cedrus libani A. Rich.) using paracone and centriod methods in Turkey

In this study, the most suitable methods for estimating tree bole volume were tested on seventy-six Brutian pine (Pinus brutia Ten.) and fourty-five Taurus cedar (Cedrus libani A. Rich.) trees. The volume of each tree bole was predicted by utilizing Paracone model, Centroid sampling, Huber formula, and local volume table (LVT) for Brutian pine and Taurus cedar. Volume predictions were then evaluated with “true” volume of every tree that was calculated through summing up the volumes of sub-sections (approximately one meter in length) using Smalian’s formula. The mean errors of Paracone model estimation of the tree bole volumes were not significant for both Brutian pine and Taurus cedar and less than those obtained from the Centroid sampling, Huber’s formula, and LVT. When four formulas were compared, the Paracone method valuation was clearly more accurate, and mean error of Paracone method was not significant at 0.05 confidence level.

(RE)Ba2Cu3O7-δ and the Roeser-Huber Formula.

We apply the Roeser–Huber formula to the (RE)BaCuO (REBCO with RE= rare earths) high- superconducting material class to calculate the superconducting transition temperature, , using the electronic configuration and the crystallographic data. In a former publication (H. P. Roeser et al., Acta Astronautica 2008, 62, 733–736), the basic idea was described and was successfully calculated for the YBaCuO compound with two oxygen doping levels 0.04 and 0.45, but several open questions remained. One of the problems remaining was the determination of for the 0.45 sample, which can be explained regarding the various oxygen arrangements being possible within the copper-oxide plane. Having established this proper relation and using the various crystallographic data on the REBCO system available in the literature, we show that the Roeser–Huber equation is capable to calculate the of the various REBCO compounds and the effects of strain and pressure on , when preparing thin film samples. Furthermore, the characteristic length, x, determined for the REBCO systems sheds light on the size of the -pinning sites being responsible for additional flux pinning and the peak effect.

Estimation of Over- and Under-Bark Volume of Scots Pine Timber Produced by Harvesters

Harvesters produce one third of timber in Czechia. The aim of this study was to analyze the over- and under-bark volume estimates of Scots pine (Pinus sylvestris L.) timber produced by a mid-performance harvester. The data were collected between March 2017 and June 2018. In total, 4661 stems cut into 29,834 logs were analyzed. For volume estimation, StanForD offers several price categories using various algorithms. Three of these price categories are relevant for Czech forestry—M3s, M3toDE, and M3miDE. The M3s price category is based on the estimation of partial volumes of 10 cm long sections, which are summed. Therefore, this price category represents the volume estimation closest to the true volume. By comparison, the M3toDE and M3miDE price categories use the same algorithm for volume estimation, which is based on the Huber formula using a midspan diameter rounded down to the nearest whole centimeter. The M3toDE price category underestimated the over-bark volume by 6.48% compared to the reference price category M3s. The mean log volume estimated through the M3s price category was significantly higher than the M3toDE volume both in individual grades and without grading. We found significant differences between under-bark volume estimates by the diameter band bark deduction method (DBM) and the parametric linear bark deduction method (PLM) used in harvester’s systems according to the Guidelines for Electronic Scaling of Timber for Harvesters in Czechia (GEH) for Scots pine butt logs with rough bark, and also for other logs with normal bark thickness. To obtain under-bark volume estimates of Scots pine timber that are comparable with the Guidelines for Timber Scaling in Czechia (GTS) using the parametric nonlinear bark deduction method (PNM), we recommend using the algorithm of the M3toDE price category, with double bark thickness determined by the diameter band bark deduction method.

COMPARACIÓN DE CALIDAD EN LA PRODUCCIÓN DE CARBÓN VEGETAL EN LA FINCA EL PLANTEL, MASAYA

La presente investigación tuvo como objetivo comparar la producción de calidad de carbón vegetal entre la fosa de tierra y el horno de ladrillo utilizando Eucalyptus camaldulensis, se seleccionaron árboles con diámetros entre 20-30 cm y mayores de 30 cm. Por cada categoría diamétrica se emplearon cinco árboles para un total de diez individuos, se tumbaron los árboles con la técnica de tala dirigida, con hacha a partir de 30 cm del suelo. Se procedió a medir la longitud de la troza en metros empleando una cinta métrica para la medición del diámetro medio. Se calculó el volumen del fuste limpio utilizando la fórmula de Smalian, posteriormente se trasladó trozas y ramas al sitio de carbonización, se depositaron por clase diamétrica donde se calculó el volumen empleando la fórmula de Huber, para la cubicación de las ramas se empleó el método de metro estéreo. Para la clase diamétrica de 20 a 30 cm se utilizó un volumen de 4.48 m3 y para mayor de 30 cm, 6.55 m3. Finalizado el proceso de carbonización se obtuvieron ocho sacos en la fosa de tierra, equivalente a 0.217 m3, en el horno de ladrillo se obtuvieron 18 sacos lo que representa 0.496 m3. Comparando los estándares de calidad de la FAO, con los obtenidos en este estudio, son aceptables, se concluye que el método de producción de horno de ladrillos usando arboles mayores de 30 cm es el mejor método para la producción de carbón vegetal. DOI: http://dx.doi.org/10.5377/calera.v13i21.1677

PREDICTION OF THE ERROR GENERATED BY SMALIAN'S AND HUBER'S FORMULAE IN VOLUME MEASUREMENTS OF Pinus caribaea (MORELET).

One of the common methods of volume estimation is the use of mathematical equations.Among such equations, Huber's, Smalian's and Newton's formulae are commonly usedand it is believed that Newton's formula which uses bottom, mid and top diameter of thelog and log length gives most precise volume estimations than Smalian's or Huber'sformulae. The latter two equations use only log length and end diameters and middiameter respectively. Usually for volume calculations Huber's formula is used due to theinvolvement of less measurements (mid diameter and log length)Present study was conducted in the 26 year old Pinus caribaea plantation in YagiralaForest Reserve situated in the low country wet zone of Sri Lanka. In order to representthe whole area of the forest, stratified random sampling method was used and one O.OShasample plot was laid in each stratum. Altogether 3 plots were selected.Each tree was divided into twelve one meter long sections using a ranging staff. Threediameters i.e., bottom, mid and top diameters of each section were measured using theSpiegel relascope. Other than section diameters, diameter at breast height (dbh) of thetree was measured using the diameter tape.Cumulative section volumes per each tree were calculated separately from Im to 12musing Huber's, Smalian's and Newton's formulae. other than the above method volumewas calculated using section lengths separately up to twelve meter long sections usingNewton's formula to test whether log length affect the Newton's volume. When testedthere was no significant difference between two volume types. However, for furtheranalysis Newton's volume calculated using the sectio•. length separately was used.For each cumulative volume (i.e., lm to 12m) calculated using different formulae werestatistically tested using one way ANOVA. According to the results 6m is the maximumlength for Huber's formula to predict the volume accurately. However it does not show asignificant difference between Smalian's and Newton's formulae up to twelve metersection length.Generally Huber's formula underestimates and Smalian's formula overestimates thevolume. Therefore it is recommended to use Huber's formula for volume calculations dueto it's ease of use, keeping the log length shorter than 6m.

Evaluating the precision of growing stock estimation and determination of industrial and fuel wood volumes of beech trees in northern of Iran

The precision of growing stock were assessed. Industrial & fuel wood volumes of beech trees in Shanderman District was surveyed. For this purpose, 10% of the annual marked trees for loggings were randomly selected in five parcel from this District. After measuring the diameter at breast height (DBH) to estimate the volume of trees by Tariff table, the trees were cut; the volumes of the industrial woods of trees were computed by using Huber's formula. The volume of fuel woods with diameter above 12 cm also were calculated by Huber's method and the diameter below 12 cm were estimated as ester. The results indicated that there were significant differences between estimation of total tree volumes by Tariff table and the total volumes of cut trees at 0.01 confidence levels. The suitable model for relationship between DBH and total volumes was a parabolic model. Industrial and fuel wood volumes of beech trees were 68.9% and 31.1% in the study area, respectively (at 95% confidential). The mean industrial volume of beech trees to total volume was between 61.1%&76.7% and fuel wood volume was between 26.49%&35.71%.

Comparison of formulae for estimating tree bole volumes of Pinus sylvestris

Tree bole volumes of 103 Scots pine (Pinus sylvestris L.) were estimated using nine methods (paracone, centroid, control-variate with one and two measurement points, Huber's formula, antithetic method using importance sampling, standard volume table, local volume table, importance sampling using one and two measurement points, and a taper equation). These estimates were compared with “true” volume of each tree bole which was determined by aggregating the volumes of measured short sections (average 1m) using Smalian's formula. The antithetic method performed well in terms of mean square error and tolerance intervals, which indicate the precision of the estimates. For both importance and control-variate sampling, better precision of the estimate may be achieved by taking measurements at two positions along a stem. The results showed that the antithetic method, importance sampling and control-variate method with two measurement points, paracone and centroid methods are useful alternatives to local volume tables and other standard formulae and are recommended for tree bole volume estimations of Scots pine in Turkey. However, in practice, convenience and economics play an important a role in the decision whether to use given estimation methods. On that basic, the paracone or centroid method may be recommended for use in tree volume estimating, as these are the easiest methods to apply, are less time consuming than other methods and show very acceptable statistical performance.

Stammholz-Volumenbestimmung über Mittendurchmesser und Mittenabholzigkeit | Determination of stemwood volume using mid-diameter and taper

The volume of stemwood can be determined if in the middle of the log, measurements are taken from the diameter and from the shaft's slope. Huber's formula provides an exact measurement for stumps of the cylinder and the apollonian paraboloid, but underestimates the volume for stumps of the cone and the neiloid.

Impact of an intervention to improve treatment-seeking behavior and prevent sexually transmitted diseases among Nigerian youths

Background: Interventions to treat STDs have been reported to reduce HIV incidence. Interventions to improve treatment-seeking for STDs may impact on the duration and prevalence of STDs. Nigeria has high rates of STDs and an increasing incidence of HIV. Objective: To evaluate the impact of an intervention on STD treatment-seeking behavior and STD prevalence among Nigerian youth. Methods: A randomized controlled trial in 12 schools in Edo State was conducted to evaluate an intervention to improve STD treatment-seeking and STD treatment provision. The intervention, based on formative research, consisted of community participation, peer education, public lectures, health clubs in the schools, and training of STD treatment providers, including those with no formal training. A questionnaire measured outcomes before and 10 months into the intervention. The effect of the intervention among four randomly selected intervention schools compared to eight randomly selected control schools was assessed using logistic regression with Huber's formula to account for school clusters. Results: One thousand eight hundred and ninety-six and 1858 youths 14–20 years of age were enrolled in the pre-and post-intervention surveys. Youths in the intervention schools, compared to control schools, reported statistically significant improvements in knowledge of STDs, condom use, partner awareness that the youth had an STD, and STD treatment-seeking behavior. Treatment by private physicians increased (OR=2.1, 95% CI=1.1–4.0), and treatment by patent medicine dealers or pharmacists decreased (OR=0.44, 95% CI=0.22–0.88). The reported prevalence of STD symptoms in the past 6 months was significantly reduced in the intervention compared to control schools (OR=0.68, 95% CI=0.48–0.95). Conclusion: Significant improvements in treatment-seeking for STD symptoms can be effected among Nigerian youths. The prevalence of reported STD symptoms can be decreased by improving treatment-seeking for and awareness of STDs.

Testing accuracy of log volume calculation procedures against water displacement techniques (xylometer)

The accuracy of three traditional formulas to calculate log volumes (Smalian, Huber, and Newton) and three recent methods (cubic splines, centroid sampling, and overlapping bolts) were compared and tested against volumes determined by the water-displacement technique (xylometer). Fifty-two felled trees were measured in a Pinus elliottii Engelm. plantation. The accuracy of these six procedures was analyzed considering total and merchantable outside bark volumes with 1-, 2-, 4-, and 6-m log lengths. The results showed that Huber's formula was superior for all volumes and log lengths considered. Centroid and Newton had a similar performance to Huber but with some higher errors. As expected, Smalian was the procedure with the worst performance. When log lengths of 1 and 2 m were employed, all procedures used to calculate total volume presented errors lower than 4.77%. However, the errors increased when the merchantable volume involves a large top diameter (veneer volumes, for example) or for calculating volumes from trees with large diameters. The results of this and other research have shown that Huber's formula has been accurate for several species, ages, geographic regions, etc. Thus, Huber's formula could be used in the majority of circumstances with log lengths greater than 2 m, reducing drastically the costs and sampling effort.

Testing accuracy of log volume calculation procedures against water displacement techniques (xylometer)

The accuracy of three traditional formulas to calculate log volumes (Smalian, Huber, and Newton) and three recent methods (cubic splines, centroid sampling, and overlapping bolts) were compared and tested against volumes determined by the water-displacement technique (xylometer). Fifty-two felled trees were measured in a Pinus elliottii Engelm. plantation. The accuracy of these six procedures was analyzed considering total and merchantable outside bark volumes with 1-, 2-, 4-, and 6-m log lengths. The results showed that Huber's formula was superior for all volumes and log lengths considered. Centroid and Newton had a similar performance to Huber but with some higher errors. As expected, Smalian was the procedure with the worst performance. When log lengths of 1 and 2 m were employed, all procedures used to calculate total volume presented errors lower than 4.77%. However, the errors increased when the merchantable volume involves a large top diameter (veneer volumes, for example) or for calculating volumes from trees with large diameters. The results of this and other research have shown that Huber's formula has been accurate for several species, ages, geographic regions, etc. Thus, Huber's formula could be used in the majority of circumstances with log lengths greater than 2 m, reducing drastically the costs and sampling effort.

Comparison between predicted volumes estimated by taper equations and true volumes obtained by the water displacement technique (xylometer)

The objective of this paper was to compare volumes estimated by taper equations to true volumes obtained by the water displacement technique (xylometer). Four previously published models and a fifth-degree polynomial were analyzed. Three sets of diameters measured on 52 fallen trees from Pinus elliottii Engelm. var. elliottii were used to fit the models. Clark et al.'s (1991; USDA For. Serv. Southeast. For. Exp. Stn. Res. Pap. No. SE-282) model was the best to predict diameters along the stem, merchantable volume, and total volumes. Max and Burkhart's (1976; For. Sci. 22(33): 283-289) model also had an excellent performance. The results still showed that the normal comparison between volumes estimated by integration of taper equations to those estimated by Smalian or Huber's formula (usual procedure) underestimates the true error which is achieved by comparison with true volumes (xylometer).

Estimating the volume of Australian hardwoods using centroid sampling

Summary Centroid sampling was tested on 18 sample trees of Flindersia brayleyana and 124 sample trees of five species of Eucalyptus all of which were measured in detail. Volumes of the main bole of each tree and of logs (length approx. 6 m) derived from each bole were estimated using both Huber's formula and centroid sampling. These estimates were compared with ‘true’ volume obtained by summing the volumes derived using Smalian's formula of all the measured short sections comprising the main bole and each log respectively. The mean error of the centroid estimate of volume of the main bole was not significant for Eucalyptus sieberi and E. diversicolor and was less than that derived from Huber's formula for all species except E. regnans. When all species were combined, the centroid estimate was clearly more accurate, its mean error (-2%) being just significant (p=0.046). Centroid sampling also gave more accurate estimates of the volume of the component logs. Results of this study and earlier work suggest that centroid sampling is applicable to tree species of both excurrent and deliquescent growth habit.