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

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.

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

FLORESTA ◽

10.5380/rf.v40i4.20326 ◽

2010 ◽

Vol 40 (4) ◽

Cited By ~ 2

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.

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

Scientia Agraria Paranaensis ◽

10.18188/sap.v19i2.23274 ◽

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.

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

FLORESTA ◽

10.5380/rf.v43i4.29928 ◽

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.

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The Efficiency of Sampling Methods for Dendrometric Estimates of Thinned Stands of Pinus taeda L. in Santa Catarina, Brazil

Journal of Agricultural Science ◽

10.5539/jas.v11n17p218 ◽

2019 ◽

Vol 11 (17) ◽

pp. 218

Author(s):

Klerysson Julio Farias ◽

Thiago Floriani Stepka ◽

Marcos Felipe Nicoletti ◽

Luis Paulo Baldissera Schorr ◽

Geedre Adriano Borsoi ◽

...

Keyword(s):

Pinus Taeda ◽

Relative Error ◽

Relative Efficiency ◽

Sampling Methods ◽

Alternative Methods ◽

Santa Catarina ◽

Area Method ◽

Fixed Area ◽

Pinus Taeda L ◽

Installation Time

This study aimed to compare the efficiency of the sampling methods: Fixed Area, Bitterlich, Prodan and Modified Prodan to estimate the commercial volume and other dendrometric estimators for a 34 years old of Pinus taeda L. stands located in Campo Belo do Sul, Santa Catarina, Brazil. It were distributed a total of 10 sample units of the following methods: Fixed Area with 200, 400 and 500 m² of area, Bitterlich, Prodan and Modified Prodan were distributed, both with 6, 7, 8, 9 and 10 trees. In addition to collecting dendrometric data, the installation time of the sample units was timed, whereby the relative efficiency for each method was calculated. The comparison between the harvest volumes and the volumes estimated by the methods was performed by the Skott Knott test, and the results that did not differ statistically were weighted by the parameters of relative error, relative efficiency and proximity to harvest. All variations of the Modified Prodan and Prodan methods had sample insufficiency. The number of trees per hectare presented higher values for the 200 m² Fixed Area method and lower values for Prodan with 10 trees. Prodan with 6 trees got the shortest time. The Bitterlich method obtained sample adequancy at 10% error and presented the best result. Among the alternative methods to Fixed Area, Modified Prodan with 7 trees can be indicated for pilot inventory. However, when more precise results are needed, the Bitterlich method is indicated.

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

FLORESTA ◽

10.5380/rf.v45i3.35410 ◽

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.

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

Southern Journal of Applied Forestry ◽

10.1093/sjaf/20.4.177 ◽

1996 ◽

Vol 20 (4) ◽

pp. 177-181 ◽

Cited By ~ 3

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.

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

Southern Journal of Applied Forestry ◽

10.1093/sjaf/6.2.115 ◽

1982 ◽

Vol 6 (2) ◽

pp. 115-119 ◽

Cited By ~ 8

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.

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A 10-Year Evaluation of Prescribed Winter Burns in Uneven-Aged Stands of Pinus-Taeda L and P. Echinata Mill - Woody Understorey Vegetation Response

International Journal of Wildland Fire ◽

10.1071/wf9930013 ◽

1993 ◽

Vol 3 (1) ◽

pp. 13 ◽

Cited By ~ 12

Author(s):

MD Cain

Keyword(s):

Pinus Taeda ◽

Prescribed Burning ◽

Basal Area ◽

Vegetation Response ◽

Understorey Vegetation ◽

Single Tree ◽

Pine Regeneration ◽

Single Tree Selection ◽

Pinus Taeda L

The effects of burning cycles and pine basal area levels were assessed on natural pine regeneration and hardwood development in uneven-aged stands of loblolly and shortleaf pines (Pinus taeda L. and P. echinata Mill.). The treatments included an unburned control and prescribed winter burns at 3-, 6-, and 9-yr intervals. Basal area treatments were 9, 14, 18, and 23 m2 ha-1 for the merchantable-pine component and were maintained on a 6-yr cutting cycle using single-tree selection. Ten years after the study was initiated, density and quadrat stocking of pine regeneration were negatively correlated with overstorey basal area. The 6-yr burning cycle had higher pine density and better quadrat stocking of pine regeneration compared with any other bum treatment mainly because the 6-yr burning cycle coincided with a bumper pine seedcrop and the 6-yr cutting cycle. Recurring fires tended to result in reduced size of hardwood competition but had less impact on hardwood density. When considering a prescribed burning program in uneven-aged stands of loblolly and shortleaf pines, more attention should be given to density, quadrat stocking, and size of established pine regeneration and to expected seedcrops rather than to the prosecution of rigid burning schedules.

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Thinned Loblolly Pine Stand Growth Improved by Early Hardwood Suppression

Southern Journal of Applied Forestry ◽

10.1093/sjaf/15.1.22 ◽

1991 ◽

Vol 15 (1) ◽

pp. 22-27

Author(s):

Terry R. Clason

Keyword(s):

Pinus Taeda ◽

Loblolly Pine ◽

Volume Growth ◽

Basal Area ◽

Growth Data ◽

Stand Growth ◽

Pinus Taeda L

Abstract A hardwood suppression treatment applied to a 7-year-old, loblolly pine (Pinus taeda L.) plantation enhanced projected productivity through a 35-year rotation that included three commercial thinnings. By age 22, growth data showed that hardwood removal treatments had larger pines and smaller hardwoods than check treatments. Fifteen-year pine basal area and merchantable volume growth on hardwood removal plots exceeded the check plots by 25 and 27%. Projected growth between ages 22 and 35 indicated that 28 years after early hardwood removal thinned plantation merchantable volume yields improved by 840 ft³ per acre. South. J. Appl. For. 15(1):22-27.

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Eight-Year Performance of Loblolly Pine with Pisolithus Ectomycorrhizae on a Good-Quality Forest Site

Southern Journal of Applied Forestry ◽

10.1093/sjaf/12.4.275 ◽

1988 ◽

Vol 12 (4) ◽

pp. 275-280 ◽

Cited By ~ 22

Author(s):

Donald H. Marx ◽

Charles E. Cordell ◽

Alexander Clark

Keyword(s):

Pinus Taeda ◽

Loblolly Pine ◽

Basal Area ◽

Site Index ◽

Forest Site ◽

Water Deficits ◽

Growing Seasons ◽

Area Growth ◽

Pinus Taeda L ◽

Crown Closure

Abstract Loblolly pine (Pinus taeda L) seedlings with different initial amounts of Pisolithus tinctorius (Pt) ectomycorrhizae (Pt index 0, 27, 46, 68, or 88) were planted on a good-quality site (site index 90 ft at age 50) in southwest Georgia. After 8 years and crown closure, trees with Pt indices of 88 and 68 had significantly better survival and greater heights, diameters, volumes, and green weights per tree and per ac than nursery-run, control seedlings (Pt index 0). Volume and weight yields per ac were over 50% greater and volume and weight yields per tree were over 20% greater for trees in the Pt index 88 treatment than they were for control trees. A special statistical analysis indicated that average per ac volume was positively correlated with initial Pt index values larger than 58. Tree-ring analyses showed that trees with a Pt index of 88 had significantly greater annual basal area growth than controls during growing seasons with water deficits of 8 to 13 in. Annual growth did not differ when water deficits were greater or less than these amounts. After 8 years, Pt basidiocarps were present throughout the study site. Mycorrhizal treatment integrity may have been lost after 3 or 4 years. South. J. Appl. For. 12(4):275-280

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