scholarly journals Precision, efficiency and cost of shapes of fixed area plots for plantation ages of Pinus taeda L. in Santa Catarina State

2020 ◽  
Vol 19 (2) ◽  
pp. 124-131
Author(s):  
Alois Zator Filho ◽  
Myrcia Minatti ◽  
Antonio Pedro Fragoso Woycikievicz ◽  
Jonathan William Trautenmuller ◽  
Nelson Yoshihiro Nakajima
Keyword(s):  
Lower Cost ◽  
Sampling Error ◽  
Basal Area ◽  
Average Diameter ◽  
Measurement Time ◽  
Efficiency Cost ◽  
Fixed Area ◽  
Different Shapes ◽  
Pinus Taeda L ◽  
Area And Volume

Generally, the forest populations are extensive and frequently require to be inventoried in short term, where the implementation of forest inventory is closely linked to the sampling theory. With objective to compare three different shapes of fixed area plots to estimate parameters of the forest as average diameter, basal area, the number of trees and volume per hectare, evaluating the respective precision, relative efficiency, cost and measurement time in four different ages. The rectangular plot had presented better precision to estimate the average DBH, number of trees and basal area and the circular plot with better precision for volume per hectare. About efficiency, the square plot had presented the best efficiency for the variable average DBH, basal area and volume and the circular plot was the most efficient for the numbers of trees ha-1. The square plot also had shown the lower cost and measurement time to estimate the variables evaluated. The rectangular plot had presented the best precision in the estimative of the variables, as well as, the lower sampling error in the most of the cases evaluated in this study, following the circular plot, and the square plot with lower precision. In relation to the efficiency, the square plot had presented the best performance and the rectangular plot the worst performance in all age classes and evaluated variables. The square plots as the best plot shape to estimate the variables average DBH, number of trees, basal area and volume per hectare.

scholarly journals Precision and accuracy of sampling methods in thinned Pinus taeda L. stands

FLORESTA ◽  
2022 ◽  
Vol 52 (1) ◽  
pp. 045
Author(s):  
Rodrigo Otávio Veiga Miranda ◽  
Felipe De Antoni Zarpelon ◽  
Síntia Valério Kohler ◽  
Alvaro Augusto Vieira Soares ◽  
Izabele Domingues Soares Miranda ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Sampling Methods ◽  
Sampling Error ◽  
Basal Area ◽  
Population Means ◽  
Starting Point ◽  
Fixed Area ◽  
Precision And Accuracy ◽  
Pinus Taeda L ◽  
Area And Volume

Different sampling methods can be used in forest surveys. It is important to know the precision and accuracy of these sampling methods, and which one is the most appropriate in specific conditions of the forest population. The aim of this study was to compare estimates of a forest inventory performed by different sampling methods with forest census results. The sampling methods evaluated were the fixed-area method and the variable-area methods of Bitterlich, Prodan, and Strand. The data were obtained in a 15-year-old thinned stand of Pinus taeda L., located in the municipality of Teixeira Soares, southern Brazil, with a total area of 12.80 ha. Initially, the forest census was carried out, and subsequently, the sample units for each sampling method were distributed in the stand, with a common starting point. The variables used to compare the sample results with the census means were quadratic diameter, number of trees, basal area, and volume, per hectare. Precision and accuracy were evaluated by sampling error and whether the confidence intervals covered the population means, respectively. The fixed-area and Bitterlich methods stood out in precision for all variables analysed. The fixed-area, Bitterlich and Strand methods with proportion to height provided more accurate estimates. The Prodan method provided inaccurate and imprecise estimates for the variables under analysis, except for the quadratic diameter.

scholarly journals EFICIÊNCIA DE DUAS VARIAÇÕES ESTRUTURAIS DO MÉTODO DE AMOSTRAGEM DE ÁREA FIXA EM PLANTAÇÕES DE Pinus taeda

FLORESTA ◽  
2013 ◽  
Vol 43 (4) ◽  
pp. 621
Author(s):  
João Paulo Druszcz ◽  
Nelson Yoshihiro Nakajima ◽  
Sylvio Pellico Netto ◽  
Sebastião do Amaral Machado ◽  
Nelson Carlos Rosot ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Relative Efficiency ◽  
Block Design ◽  
Basal Area ◽  
Average Diameter ◽  
Breast Height ◽  
Variable Diameter ◽  
Randomized Block Design ◽  
Fixed Area ◽  
Pinus Taeda L

Este estudo foi conduzido em três diferentes condições de plantações de Pinus taeda L., sem desbastes, com 10, 9 e 7 anos de idade, 2.000 árvores por hectare e diferentes inclinações no terreno, localizados no Estado do Paraná. O objetivo foi avaliar a eficiência do inventário florestal, utilizando-se a amostragem de área fixa com a estrutura de parcela circular (PC) e conglomerado em cruz (CC), através da análise do comportamento quanto às precisões e eficiências relativas nas estimativas das seguintes variáveis: diâmetro médio (cm), número de árvores por ha, área basal (m2/ha) e volume total (m3/ha). Para isso, utilizou-se o delineamento em blocos casualizados com 40 unidades amostrais para a PC e 10 unidades para o CC, sendo este composto por 4 subunidades circulares. Concluiu-se que, para as variáveis diâmetro médio (cm), número de árvores (N/ha), área basal (m2/ha) e volume total (m3/ha), indica-se a utilização do método de área fixa com PC, tendo em vista a maior eficiência no levantamento dessas variáveis.Palavras-chave: Eficiência relativa; precisão; reflorestamento. AbstractStructural efficiency of two variations of method of sampling of fixed area in plantations of Pinus taeda. This study was carried out in three different stands of Pinus taeda L., unthinned and aged 10, 9 and 7 years. The stands have 2.000 trees per hectare and are located in Parana State. The aim was to evaluate the efficiency of inventories using circular plot (PC) and cross cluster (CC) by analyses of behavior towards accuracies and relative efficiencies for estimation of the following variables: average diameter at breast height, number of trees, basal area and total volume per hectare. For this study, it was taken a sample of 40 units to the PC structure and 10 units for the CC structure, which is composed of four circular subunits, and it was used the randomized block design. It was concluded that for the variable diameter (cm), number of trees (ha), basal area (m2/ha) and total volume (m3/ha) it is indicated the use of PC, since its greater efficiency in the survey of these variables.Keywords: Relative efficiency; accuracy; reforestation.

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.

scholarly journals Utjecaj intenziteta prorjeda na rast azijske bukve (Fagus orientalis Lipsky) u plantažama u Trabzonu na sjeveroistoku Turske

2019 ◽  
Vol 143 (5-6) ◽  
pp. 231-240
Author(s):  
Ayhan Usta ◽  
Ibrahim Turna ◽  
Esengül Genc ◽  
Yavuz Okunur Kocamanoglu ◽  
Selvinaz Yilmaz ◽  
...  
Keyword(s):  
Basal Area ◽  
Average Diameter ◽  
Average Height ◽  
Sample Plot ◽  
Fagus Orientalis ◽  
Thinning Intensity ◽  
Diameter Increment ◽  
Oriental Beech ◽  
Fagus Orientalis Lipsky ◽  
Area And Volume

In this study, the effects of first thinnings having different intensities in oriental beech (Fagus orientalis Lipsky) plantation areas were investigated in terms of diameter and height growth of trees. Sample plots were chosen from oriental beech plantation areas which are within the boundaries of Maçka–Yeşiltepe and Vakfıkebir districts of Trabzon province, Turkey. With removing of 0%, 10%, 25% and 40% of basal area in a hectare of stands which are in sapling stage, sample plots were established by applying thinnings which are in four different intensities (control, light, moderate, strong). After the thinning applications, basal areas were calculated by measuring diameters and heights of trees in established sample plots in order to reveal stand growth. The effects of thinnings were revealed related to some stand characteristics (average diameter, basal area, average height, relative diameter increment, etc.) and determined chosen trees. The effect of thinning intensity on average diameter, basal area, and volume values is statistically important in every two plantations. 2-year results showed that thinning increased the diameter increment significantly, and the increase in diameter increment was positively correlated with the thinning intensity in both experiments. Moreover, increments of diameter, height, basal area, and volume were higher in Maçka-Yeşiltepe experiment than in Vakfıkebir experiment. But, the values of moderate and strong thinning intensities applied in Vakfıkebir were close to each other. When all the results are evaluated, application of strong thinning intensity for Yeşiltepe sample plot, the moderate thinning intensity for Vakfıkebir sample plot is seen appropriate by us in terms of both stand development.

scholarly journals An Application of LiDAR in a Double-Sample Forest Inventory

2004 ◽  
Vol 19 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Robert C. Parker ◽  
David L. Evans
Keyword(s):  
Forest Inventory ◽  
Sampling Error ◽  
Phase 1 ◽  
Basal Area ◽  
Phase 2 ◽  
Volume Estimate ◽  
Regression Estimate ◽  
Regression Estimators ◽  
Mean Differences ◽  
Area And Volume

Abstract Multireturn LiDAR data (2-m posting) were used in a double-sample forest inventory in central Idaho. Twenty-four 15-plot (0.2 ac) strips were established with a real-time Differential Global Positioning System. Tree dbh and height were measured on every 5th plot. Volume and basal area were computed for eight encountered species. LiDAR trees were selected with a focal max filter and height computed as the z-difference between interpolated canopy and DEM surfaces. LiDAR-derived trees/ac, height, and dbh had mean differences of −4.4 trees, −10.7 ft, and −1.01 in. from ground values. Four dbh-height models were fitted. Predicted dbh was used to compute LiDAR estimates of basal area and volume on 360 Phase 1 plots. Phase 2 LiDAR estimates on 60 plots were computed by randomly assigning heights to species classes using a 500-iteration Monte Carlo simulation. Regression estimators for Phase 2 ground and LiDAR ft3 and ft2 were computed by single and composite species. Phase 1 estimates were partitioned to obtain species volumes. The regression estimate of composite volume was partitioned by percent species distribution of trees, basal area, and volume. There was no statistical difference between individual and partitioned composite species estimates. Sampling error was ±11.5% on a mean volume estimate of 1,246 ft3/ac with standard error ±72.98 ft3/ac. West. J. Appl. For. 19(2):95–101.

scholarly journals EUCALYPTUS STAND SAMPLE PLOTS COMPARED: FIXED AREA AND FIXED NUMBER OF TREES

2016 ◽  
Vol 40 (3) ◽  
pp. 529-533
Author(s):  
Danilo Roberti Alves de Almeida ◽  
Helio Garcia Leite ◽  
Eric Bastos Gorgens
Keyword(s):  
Null Hypothesis ◽  
Sampling Methods ◽  
Basal Area ◽  
Average Diameter ◽  
Fixed Number ◽  
T Test ◽  
Eucalyptus Forest ◽  
Fixed Area ◽  
Number Of Stems

ABSTRACT This study compares sampling methods based on plots of fixed area and based on a fixed number of trees. The study was conducted in a Eucalyptus forest surveyed using three plot types: rectangular with fixed area, circular with fixed area and fixed number of trees. The estimation accuracies were evaluated for the average diameter per plot and for the number of stems, the basal area and the volume per plot. The null hypothesis of equality between the sampling methods was assessed by t-test. No significant differences were found between the three sampling methods.

scholarly journals Growth Responses Following Herbicide Release of Loblolly Pine from Competing Hardwoods in the Virginia Piedmont

1996 ◽  
Vol 20 (4) ◽  
pp. 177-181 ◽  
Author(s):  
Harold E. Quicke ◽  
Dwight K. Lauer ◽  
Glenn R. Glover
Keyword(s):  
Pinus Taeda ◽  
Loblolly Pine ◽  
Basal Area ◽  
Growth Responses ◽  
Virginia Piedmont ◽  
Herbicide Treatments ◽  
Untreated Check ◽  
Pinus Taeda L ◽  
Better Than ◽  
Area And Volume

Abstract The objective of this study was to identify effective herbicide treatments for the release of loblolly pine (Pinus taeda L.) from competing hardwoods 7 yr after treatment. The study site was a hardwood-to-pine conversion area that had been chopped and burned. Treatments included two groups of herbicides: (1) imazapyr at 1.0 lb ae/ac used alone or in combination with metsulfuron or glyphosate, and (2) glyphosate at 1.5 lb ae/ac used alone or in combination with metsulfuron. Broadcast herbicide treatments were applied in September, 1985, during the second growing season. All treatments were effective in controlling hardwoods, with the least effective treatment decreasing hardwood basal area by 55% relative to the untreated check. The pine crop trees responded with increased diameter, height, basal area, and volume. The increase in total pine volume outside bark over the untreated check ranged from 163 to 640 ft3/ac (22% to 85%) and the increase in pine basal area ranged from 13 to 40 ft2/ac (27% to 83%). No treatment resulted in significant pine mortality. Although pine height growth was stunted the year following treatment, at age 9, mean height gains on treated plots ranged from 2.7 ft to 5.6 ft. Treatments containing imazapyr performed better than treatments with glyphosate alone or in combination with metsulfuron. Imazapyr at 1.0 lb ae/ac reduced hardwood basal area to 2 ft2/ac at age nine compared to 25 ft2/ac on the untreated check plots. There was, therefore, little room for improvement from additives, indicating that combinations with lower rates of imazapyr, comparable to today' s operational rates, may be more appropriate. South. J. Appl. For. 20(4):177-181.

Interim Models for Basal Area and Volume Projection of Uneven-Aged Loblolly-Shortleaf Pine Stands

1982 ◽  
Vol 6 (2) ◽  
pp. 115-119 ◽  
Author(s):  
Paul A. Murphy ◽  
Robert M. Farrar
Keyword(s):  
Pinus Taeda ◽  
Basal Area ◽  
Selection System ◽  
Pinus Echinata ◽  
Shortleaf Pine ◽  
Independent Variables ◽  
Elapsed Time ◽  
Volume Production ◽  
Pinus Taeda L ◽  
Area And Volume

Abstract Equations are presented for estimating current volume, projected basal area, and projected volume for stands of loblolly-shortleaf (Pinus taeda L.-Pinus echinata Mill.) pine managed under the selection system. The independent variables are initial stand basal area and elapsed time. The estimates should provide a guide to the cubic-foot volume production that might be expected from stands on average sites (site indices 80-90 ft.), medium basal areas (30 to 70 sq. ft.) and time periods of 10 years or less.

A TAPER AND VOLUME TABLE AND VOLUME FORMULAE FOR BLACK SPRUCE IN SASKATCHEWAN

1960 ◽  
Vol 36 (3) ◽  
pp. 242-277
Author(s):  
C. L. Kirby
Keyword(s):  
Tree Species ◽  
Black Spruce ◽  
Basal Area ◽  
Average Diameter ◽  
Rapid Methods ◽  
Volume Table ◽  
Area And Volume

A taper and volume table has been developed for black spruce in Saskatchewan. Comparisons with other taper and volume tables show that volume formulae are as accurate as volume tables and that it is not necessary to have a separate volume table for each tree species. Also included are more rapid methods for the calculation of average diameter, basal area and volume.

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