New and composite point sampling estimates

2010 ◽  
Vol 40 (11) ◽  
pp. 2234-2242 ◽  
Author(s):  
John Paul McTague
Keyword(s):  
Sampling Method ◽  
Sampling Methods ◽  
Basal Area ◽  
Population Parameters ◽  
Critical Height ◽  
Sampling Methodology ◽  
Stand Volume ◽  
Point Sampling ◽  
Repeated Sampling ◽  
Angle Count Sampling

A new estimator for basal area is introduced that is based on the concepts of angle count and angle summation sampling. Using the ratio of the angle count basal area factor and the angle summation (borderline) factor, it is possible to estimate stand volume without measuring the diameters and distances of the trees included in the sample. Employing simulation of repeated sampling in a 40 ha forest of known population parameters, it is demonstrated that the new sampling methodology is unbiased and weakly correlated with conventional angle count sampling. Hence, considerable gains in efficiency are made by combining the two sampling methods with composite estimators. Two applications are explored with the new composite point sampling estimates, including the use of the big basal area factor sampling method and critical height sampling using a Max and Burkhart taper formulation.

Stratified space angle-count sampling for an estimation of stand volume

2004 ◽  
Vol 34 (2) ◽  
pp. 507-508 ◽  
Author(s):  
Masahiko Nakagawa
Keyword(s):  
Basal Area ◽  
Critical Height ◽  
Easy Method ◽  
Indicator Variable ◽  
Stand Volume ◽  
Point Sampling ◽  
Stratified Space ◽  
Space Angle ◽  
Space Point ◽  
Angle Count Sampling

Stratified space angle-count sampling is a newly proposed method for estimating stand volume. This new method includes the theory and all the premises of space point sampling, as well as the following: (i) all trees taper, (ii) the box-like sampling space imagined in space point sampling is divided into several strata with the same vertical distances, (iii) the diameter of expanded tree stems in each stratum is represented at the middle of the vertical distance in each stratum. Stand volume is calculated using the following equation: V (m3/ha)=kH/Z Σ[Formula: see text] λi, where V is volume (m3/ha), k is basal area factor (m2/ha), H is the maximum tree height in the stand, Z is the number of strata in the sampling space, N is the number of trees in the stand, and λi is an indicator variable that takes the value 1 or 0, depending on whether the tree stem is in the sample or not. Since this method does not require a measurement or an estimation of a critical height, it could be an easy method for estimating stand volume.

scholarly journals Application of Point Sampling Method in Estimation of Stand Basal Area in Community Forest

2018 ◽  
Vol 1 (1) ◽  
pp. 45-54
Author(s):  
Budi Mulyana ◽  
Rohman Rohman ◽  
Ris Hadi Purwanto
Keyword(s):  
Direct Measurement ◽  
Sampling Method ◽  
Sampling Methods ◽  
Basal Area ◽  
Community Forest ◽  
Point Sampling ◽  
Community Forests ◽  
Average Value ◽  
The Difference ◽  
Materials Used

Estimation of the potency of community forest is usually done with the census approach for each forest. Sampling methods to estimate the potency of community forest are still rare. The size of community forest is relatively small, scatter, and less irregular shape, therefore the estimation of community forest potency using sampling plot is difficult to apply. The approach of sampling without a plot (plotless/ point sampling) was cheaper and faster compare to the method of sample plots and direct measurement (census) in predicting basal area. The objective of this research is determining the difference in the average value of basal area using direct measurement of stand (census) and point sampling methods. The research was carried out for 4 months in 30 community forests at Kemuning Village, Gunungkidul District. Materials used to estimate basal area with point sampling method were Spiegel Relascope and Bitterlich Stick with the value of Basal Area Factor 1. Parameters measured were diameter at breast high (dbh) for census method and the number of trees were categorized in or border for point sampling method. The result was analyzed statistically using unpaired t-student. The result showed that the average of basal area of tree in community forest with point sampling method were no significantly different from the average of basal area with census method (α = 1%). Therefore, the point sampling method can be considered as a tool in inventory at community forest

scholarly journals Angle-count sampling method for estimating forest stand volume – a practical approach

2020 ◽  
pp. 99-102
Author(s):  
Károly Rédei ◽  
Tamás Ábri ◽  
Fruzsina Szabó ◽  
Zsolt Keserű
Keyword(s):  
Sampling Method ◽  
Black Locust ◽  
Basal Area ◽  
Forest Stand ◽  
Management Planning ◽  
Stand Volume ◽  
Forest Plans ◽  
Angle Count Sampling ◽  
Stand Characteristics ◽  
Area And Volume

Point sampling, which is also known as angle-count sampling (ACS), can be considered an efficient way of estimating the basal area and volume of forest stands. It is possible to use it in forest management: providing more accurate estimates (precision <10%) of  site and stand characteristics needed for management planning. 20 black locust (Robinina pseudoacacia L.) stands were selected at final cutting age to determine the regeneration criteria based on their total volume. It was verified that at P=5% there was no difference between the main volume values of stands indicated in the relevant forest plans as well as calculated by the ACS method.  

scholarly journals COMPARAÇÃO ENTRE OS MÉTODOS DE AMOSTRAGEM DE BITTERLICH E DE ÁREA FIXA COM PARCELA CIRCULAR EM PLANTAÇÃO DE Pinus taeda

FLORESTA ◽  
2010 ◽  
Vol 40 (4) ◽  
Author(s):  
João Paulo Druszcz ◽  
Nelson Yoshihiro Nakajima ◽  
Sylvio Péllico Netto ◽  
Mauro Yoshitani Júnior
Keyword(s):  
Pinus Taeda ◽  
Sampling Method ◽  
Sampling Methods ◽  
Basal Area ◽  
Plot Sampling ◽  
Fixed Area ◽  
Plot Area ◽  
The Mean ◽  
Pinus Taeda L

Este estudo objetivou comparar o método de amostragem de Bitterlich e o de área fixa com Parcela Circular. Estes dois métodos foram avaliados quanto à precisão e eficiência na estimativa das variáveis DAP médio, número de árvores, área basal e volume total, por hectare. Foram selecionadas três condições de plantios de Pinus taeda, localizados na fazenda Boa Vista, no município de Carambeí – PR. Na análise simultânea das três condições para as estimativas das variáveis DAP médio e número de árvores, por hectare, o método de amostragem de área fixa com Parcela Circular foi o mais preciso e eficiente. Já para a análise de área basal e volume total, por hectare, o método de amostragem de Bitterlich foi o mais preciso e eficiente. Conclui-se que o método de área fixa com Parcela Circular foi mais preciso e eficiente para a estimativa das variáveis DAP médio e número de árvores, já que se trata de um método no qual a seleção dos indivíduos é proporcional à área da parcela. O método de Bitterlich, por ser um método que faz a seleção dos indivíduos com probabilidade à área basal, foi mais preciso e eficiente para a estimativa das variáveis área basal e volume total.Palavras-chave: Método de amostragem; precisão e eficiência; Pinus taeda. AbstractComparison between Bitterlich and fixed area circular plot sampling methods in Pinus taeda L plantation. This study aimed to compare the Bitterlich sampling method to the fixed area circular plot. These two methods were evaluated with respect to the accuracy and efficiency for estimating the variables mean DBH, number of trees, basal area and total volume per hectare. Three conditions for Pinus taeda plantations were selected. They were located in Boa Vista farm, Carambeí County, State of Paraná. Results showed that the fixed area circular plot was more efficient and accurate to estimate the mean DBH and the number of trees per hectare because it is a method where the trees selection is proportional to the plot area, whereas the Bitterlich method was more efficient and accurate to estimate the basal area and the total volume per hectare because the trees selection is related to the basal area.Keywords: Sampling methods; accuracy and efficiency; Pinus taeda.

scholarly journals EFFICIENCY OF THE BITTERLICH POINT SAMPLING AND THE METHOD OF FIXED AREA SAMPLING WITH STRUCTURAL VARIATIONS IN Pinus taeda PLANTATIONS

FLORESTA ◽  
2015 ◽  
Vol 45 (3) ◽  
pp. 523
Author(s):  
João Paulo Druszcz ◽  
Sebastião Do Amaral Machado ◽  
Nelson Yoshihiro Nakajima ◽  
Nelson Carlos Rosot ◽  
Roberto Tuyoshi Hosokawa
Keyword(s):  
Pinus Taeda ◽  
Sampling Method ◽  
Basal Area ◽  
Structural Variations ◽  
Point Sampling ◽  
Fixed Area ◽  
The Mean ◽  
The Cross ◽  
Pinus Taeda L ◽  
The City

AbstractThis study aimed to compare two methods of sampling, one is the method of variable area represented by the Bitterlich point (PB) sampling and the other is the method of fixed area represented by circular plots (PC) with structural variation, the cross sampling cluster (CC) and the line sampling cluster (CL). Precision and efficiency in estimation of the variables mean DBH (cm), number of trees (N/ha), basal area (m2/ha) and total volume (m3/3) in three plantation conditions of Pinus taeda L., located in the city of Carambeí, Paraná, were assessed. In simultaneous analysis of the three conditions to estimate the mean DBH and number of trees per hectare variables, the sampling method of fixed area with Circular Plot (PC) was the most accurate and efficient. The Bitterlich point sampling method (PB) was more accurate and efficient for the estimation of basal area and total volume variables. The two structures of sampling method of the fixed area with Cross Cluster (CC) and with Line Cluster (CL) demonstrated good results being the line cluster superior to the cross cluster.ResumoEficiência do método de amostragem de Bitterlich e de área fixa com variações estruturais em plantações de Pinus taeda. O estudo visou comparar dois métodos de amostragem, sendo eles o de área variável, o qual foi representado pelo método Ponto de Bitterlich (PB) e o de área fixa, representado pela Parcela Circular (PC) e as variações estruturais em Conglomerado em Cruz (CC) e Conglomerado em Linha (CL) com subunidades circulares. Foram avaliadas a precisão e eficiência para a estimativa da variável DAP médio (cm), número de árvores (N/ha), área basal (m2/ha) e volume total (m3/ha), em três condições de plantações, localizadas no município de Carambeí, PR. Na análise simultânea das três condições para a estimativa da variável DAP médio (cm) e número de árvores (N/ha), o método de área fixa com Parcela Circular (PC) foi o mais preciso e eficiente. Para a estimativa da variável área basal (m2/ha) e volume total (m3/ha), o método de área variável Ponto de Bitterlich foi mais preciso e eficiente. As duas estruturas do método de área fixa, utilizando-se o Conglomerado em Cruz (CC) e o Conglomerado em Linha (CL) apresentaram resultados precisos e eficientes, entretanto, o CL foi superior ao CC.Palavras-chave: Eficiência relativa; precisão; reflorestamento.

Effects of Sampling Method and Feed Withdrawal Period on Recovery of Microorganisms from Poultry Carcasses1

1989 ◽  
Vol 52 (7) ◽  
pp. 480-483 ◽  
Author(s):  
A. L. IZAT ◽  
M. COLBERG ◽  
C. D. DRIGGERS ◽  
R. A. THOMAS
Keyword(s):  
Sampling Method ◽  
Sampling Methods ◽  
The Other ◽  
Sampling Techniques ◽  
Withdrawal Period ◽  
Sampling Methodology ◽  
Feed Withdrawal ◽  
Plate Counts ◽  
Skin Excision ◽  
Yeasts And Molds

Five trials were conducted to evaluate the effects of four microbiological sampling techniques for determining aerobic plate counts, presumptive coliform counts, and yeasts and mold counts of broiler carcasses. The effects of feed withdrawal period on bacterial numbers was also evaluated. Sampling methods evaluated were a surface swab technique, a whole carcass rinse procedure, a breast skin rinse procedure in which the skin was excised from the breast area, and a sample blending technique that involved breast skin excision and blending. Results from these trials indicated that the whole carcass rinse procedure yielded significantly greater recovery of aerobic mesophiles than the other methods evaluated. The recovery of coliforms was significantly greater when either the whole carcass rinse or the breast blend procedure was employed. The numbers of yeasts and molds present on the prechill carcass were extremely low, and results obtained using the various sampling methods were inconsistent. Regardless of sampling methodology and type of organism enumerated, the highest counts were obtained from broilers that had not been withdrawn from feed prior to processing.

Combining taper functions and critical height sampling for unbiased stand volume estimation

1987 ◽  
Vol 17 (11) ◽  
pp. 1416-1420 ◽  
Author(s):  
Paul C. Van Deusen
Keyword(s):  
Variance Reduction ◽  
Volume Growth ◽  
Volume Estimation ◽  
Critical Height ◽  
Stand Volume ◽  
Point Sampling ◽  
Taper Function ◽  
Unbiased Estimates ◽  
Sampling Procedures ◽  
Horizontal Point Sampling

New estimators have been developed for critical height sampling that allow any taper function to be used as a variance reduction mechanism. The new estimators are compatible with current horizontal point sampling procedures and will lead to unbiased estimates of cubic volume and cubic volume growth. It is proposed that critical height sampling should replace horizontal point sampling when one upper stem measurement can be made, because horizontal point sampling relies on predicted tree volumes and the assumption that resulting stand volume predictions are unbiased.

Variance reduction in Ueno's method and cylinder sampling for forest volume estimation

1995 ◽  
Vol 25 (11) ◽  
pp. 1783-1794 ◽  
Author(s):  
Thomas B. Lynch
Keyword(s):  
Computer Simulation ◽  
Variance Reduction ◽  
Volume Estimation ◽  
Critical Height ◽  
Volume Estimate ◽  
Individual Tree ◽  
Stand Volume ◽  
Reduction Techniques ◽  
Antithetic Variates ◽  
Volume Equation

Three basic techniques are proposed for reducing the variance of the stand volume estimate provided by cylinder sampling and Ueno's method. Ueno's method is based on critical height sampling but does not require measurement of critical heights. Instead, a count of trees whose critical heights are less than randomly generated heights is used to estimate stand volume. Cylinder sampling selects sample trees for which randomly generated heights fall within cylinders formed by tree heights and point sampling plot sizes. The methods proposed here for variance reduction in cylinder sampling and Ueno's method are antithetic variates, importance sampling, and control variates. Cylinder sampling without variance reduction was the most efficient of 12 methods compared in computer simulation that used estimated measurement times. However, cylinder sampling requires knowledge of a combined variable individual tree volume equation. Of the three variance reduction techniques applied to Ueno's method, antithetic variates performed best in computer simulation.

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