Bark Volume Research Articles

Determinação do volume, do fator de forma e da porcentagem de casca de árvores individuais em uma Floresta Ombrófila Aberta na região noroeste de Mato Grosso

O objetivo deste estudo foi testar e selecionar modelos que expressam o volume com e sem casca e determinar o fator de forma e a porcentagem de casca para uma área de floresta ombrófila aberta na região noroeste de Mato Grosso. Foi realizada a cubagem rigorosa de 91 árvores para a obtenção do diâmetro, espessura de casca, altura total do fuste e volume sólido. Dez modelos volumétricos foram testados, sendo que para a seleção do melhor modelo foram usadas as estatísticas do coeficiente de determinação ajustado, erro padrão da estimativa, seguida da análise de resíduos e distribuição gráfica dos resíduos. Os modelos selecionados foram validados pela aplicação do teste L&O. O fator de forma médio obtido foi de 0,7424 e 0,7297 com e sem casca, respectivamente. O volume médio de casca foi de 0,4292 m³ (7,45% do volume total). O modelo de Schumacher-Hall foi o que melhor se ajustou aos dados de volumes com e sem casca.

Tavola di cubatura a doppia entrata per i cedui di faggio del Piemonte

Abstract: The aim of the present work is to fill a gap in the collection of available algorithms for the estimation of standing tree volume. The deficiency of such tools is especially marked when their object is represented by stands undergoing strong or rapid changes in forest structure. Such is the case of beech (Fagus sylvatica L.) coppices in Piedmont, once managed mainly for firewood, i.e., with fast rotations and a mean tree size much smaller than what observed in current stands. In addition, the structure of most of these stands was heavily impacted by selection cuttings in the early ’90s, aimed at the conversion of coppices to high forests in the long run. A single tree volume table (inclusive of branches and bark volumes) has been prepared according to the following steps: (1) selection of relevant stands, representative in their extent, density and merchantability (13 alpine valleys in 6 provinces); (2) computation of sample size according to the observed variability in the selected study areas (1085 model trees for height and volume); (3) tree measurement and data mining (statistical detection of outliers and selection of the most suitable model form for a double-entry tree volume table). The main output of the study is the volume table itself. The paramount importance of such tool for forest management is confirmed by the abundance of beech forests (136000 hectares, i.e., the second most represented forest cover type in the study region), 90% of which is still managed as coppice stands.

Bark thickness and bark volume of Pinus patula in South Africa

In South Africa, tree volume tables and volume functions are usually based on the under bark stem volume. Many forest management studies, however, give the estimated over bark volume, in which case equations are required that estimate bark volume and possibly bark thickness as a function of DBH and tree height. This study deals with the evaluation of geographical regions and tree characteristics on bark thickness and bark volume of Pinus patula in South Africa.

Alteração estrutural de áreas de florestas exploradas convencionalmente em planos de manejo, nos domínios de floresta Atlântica, Minas Gerais, Brasil

Este estudo teve como objetivo analisar as alterações nas estruturas horizontal, diamétrica e interna em áreas de planos de manejo florestal exploradas convencionalmente. Utilizaram-se indicadores e verificadores, tendo como testemunha a área de reserva legal. Decorrido o tempo de exploração florestal de cada Plano de Manejo Florestal (PMF) e comparando as áreas de manejo florestal e áreas de reserva legal, com relação a alterações na estrutura horizontal dos PMFs, o verificador densidade absoluta indicou que as áreas de manejo florestal foram iguais estatisticamente (P>0,05) às áreas de reserva legal nos PMF28, PMF29 e PMF30 e diferentes (P<0,05) no PMF16. Os verificadores dominância absoluta e volume total com casca indicaram que os estoques de área basal e volume total das áreas de manejo florestal foram iguais estatisticamente (P>0,05) às áreas de reserva legal nos PMF28, PMF30 e PMF16 e diferentes (P<0,05) no PMF29. Com relação a alterações na estrutura diamétrica dos PMFs, os verificadores distribuição da densidade absoluta, área basal e volume total com casca, por hectare e por classe diamétrica, indicaram que as áreas de manejo florestal foram iguais estatisticamente (P>0,05) às áreas de reserva legal nos PMF28, PMF29 e PMF30 e diferentes (P<0,05) no PMF16. Com relação às alterações na estrutura interna dos PMFs, o verificador infestação de cipós indicou que as áreas de manejo florestal apresentaram infestação de cipós igual estatisticamente (P>0,05) às áreas de reserva legal nos PMF29, PMF30 e PMF16 e diferente (P<0,05) no PMF28. O verificador qualidade de fuste mostrou que as áreas de manejo florestal possuem qualidade de fuste igual estatisticamente (P>0,05) às áreas de reserva legal em todos os PMFs.

Desempenho silvicultural de clones de Eucalyptus grandis em relação às árvores matrizes

Objetivando avaliar a eficiência da seleção inicial de 13 árvores-matriz para clonagem de Eucalyptus grandis e o desempenho delas em teste clonal, foram mensuradas as características dap, altura total (Ht), volume com casca (V CC), sem casca (V SC) e volume de casca (V C), bem como as cinco árvores "co-dominantes" em um raio de 10 m da matriz selecionada, para verificar a sua superioridade em relação aos seus pares. O desempenho silvicultural dos clones dessas matrizes foi avaliado aos sete anos de idade, em teste clonal instalado no delineamento em blocos ao acaso, com três repetições e parcela quadrada de 25 plantas, em espaçamento de 3 x 2 m. Com base nos resultados deste trabalho, pode-se concluir que a avaliação da superioridade em Ht da árvore-matriz em relação às árvores co-dominantes do local de seleção é um parâmetro importante para a escolha inicial de árvores-matriz. A análise multivariada foi eficaz para a alocação das matrizes em grupos divergentes, bem como para a classificação de árvores-matriz selecionadas posteriormente dentro dos grupos pré-definidos pelo método de Tocher. Existe relação significativa entre as características utilizadas para a seleção inicial das árvores-matriz e o desempenho dos clones dessas matrizes na avaliação final do teste clonal. Esses resultados possibilitam a redução do número de material genético a ser avaliado. No entanto, a instalação dos testes é imprescindível no processo de seleção, principalmente devido à existência da interação do genótipo com os efeitos ambientais.

Parsimonious and Completely Compatible Taper, Total, and Merchantable Volume Models

Abstract A parsimonious and compatible system of taper, total, and merchantable volume equations sharing a common vector of three parameter estimates was derived from Clark and Saucier's (1990) volume ratio model. Clark and Saucier's model expresses volume inside bark as a function of outside bark diameter and is itself not compatible with the derived taper equation. To ensure compatibility, models were fit to express volume outside bark as functions of diameter outside bark. By constraining the limits of integration of the taper function to go from the tip to groundline diameter, a completely compatible system of taper, total, and merchantable volume equations were developed. Systems of equations were fit using nonlinear seemingly unrelated regressions with nonlinear cross-equation constraints to account for contemporaneous correlations in the data. The system fit was found to account for at least 96% of the variation in diameter outside bark, total, and merchantable outside bark volume. FOR. SCI. 51(6):578–584.

Artificial neural networks as an alternative tool in pine bark volume estimation

The utilization of pine trees bark is receiving increasing attention. For management purposes, it is very useful to be able to estimate bark volume quantity of standing trees. This paper is concerned with the use of artificial neural network (ANN) models for accurate bark volume estimation of standing pine trees ( Pinus brutia) as an alternative to regression models. The procedure that should be followed in the development of such models is outlined. Five different nonlinear regression models were fitted to data using the Levenberg–Marquardt optimization algorithm. Because of the bias detected on the assumptions and the high error values, three-layer feed-forward cascade correlation ANN models were developed to estimate bark volume. A comparative study of both nonlinear regression models and selected cascade correlation ANN model with the structure of 4-7-1/0.9982 indicated that the ANN model performed better than the best nonlinear regression model with error values 6.02% (root mean square error) and 13.3% (Furnival's index) of the mean bark volume, respectively. Paired t-test, 45° line test and absolute deviation percentage were also used for validation of the chosen models. The results clearly demonstrate the superiority of the ANN models to the regression models due to their ability to overcome the problems in forest data, such as nonlinear relationships, non-Gaussian distributions, outliers and noise in the data. The ANN technique introduced in this study is sufficiently general and has great potential to be applicable to many forest modeling applications providing a very useful tool as an alternative to traditional regression models.

Modelling bark thickness of Picea abies with taper curves

Models predicting bark thickness at 14 different relative stem heights were derived, and factors affecting bark thickness were analyzed. The study material was collected from the tracts of the fifth National Forest Inventory (NFI) during the years 1968–1971. It consists of sample tree data measured from 1864 Norway spruce ( Picea abies) stems. Bark thickness was measured with bark gauges at the following 14 different relative heights: 1, 2.5, 5, 7.5, 10, 15, 20, 30, 40, 50, 60, 70, 80, and 90%. Linear regression models predicting bark thickness at each relative height were derived. These models were combined into an equation group in which double bark thickness at each relative height was predicted with both endogenous variables (bark thickness at neighboring relative heights) and exogenous variables (tree age, tree height, and breast height diameter). This equation group was solved with the Thomas algorithm. Predicted bark thickness values were finally joined with spline functions to form a bark curve model. The models gave unbiased estimates for both bark thickness and bark volume. The relative error for bark thickness varied from 13.7 to 27.9% and the standard error for stem volume under bark varied from 5.27 to 7.79 dm 3 depending on the amount of input data. Bark thickness was found to correlate with diameter at breast height, tree height, tree age and stem tapering. Climatic zone also clearly affected the amount of bark. By combining the models derived in this study with existing stem curve models, it is possible to accurately calculate stem volume both under and over bark for any arbitrary portion of the stem.

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.

A Mathematically Tractable Stem Profile Model for Jack Pine in Ontario

Abstract A new model was derived to describe the inside bark cross-sectional area of tree stems. It is a rational function. The inputs required by the model are outside bark tree diameter at breast height (DBH) and total tree height (H). Knowledge of a species-specific bark thickness at 1.3 m expressed in terms of input variables is also needed. Defining the model involves estimating two regression coefficients using either nonlinear or linear regression (after linearization of the model). The formula is analytically integrable and thus provides analytical inside bark volume estimates for any stem section defined by height limits. The model is analytically solvable for a stem height location at any given inside bark diameter, so that stem sections can be defined by the required inside bark diameter limits. The new model can be calibrated using either section diameter or section volume data. It is suggested that involving the ratio H/DBH in the model accounts for the influence of stand density on stem profile. The formula was calibrated for jack pine (Pinus banksiana Lamb.) in Ontario. Wider applicability of the model is supported by results obtained for sugar maple (Acer saccharum Marsh.) in Ontario and Scots pine (Pinus silvestris L.) in Finland. Comparing volume estimates from the new model with those generated by Honer's formula confirms the advantages of the new model. North. J. Appl. For. 16(3):138-143.

Comparação de diferentes métodos de amostragem, de área fixa e variável, em uma floresta de<i> Araucaria angustifolia </i>.

Este trabalho foi desenvolvido em uma Floresta de Araucaria angustifolia pertencente à Floresta Nacional de São Francisco de Paula, RS. O objetivo foi comparar quatro métodos de amostragem de área variável (Strand, Prodan, Quadrantes e Bitterlich) com o método de Área Fixa e determinar a eficiência de cada um deles nas estimativas dos parâmetros quantitativos (volume comercial com casca, número de árvores e área basal) e qualitativos (abrangência das espécies) da população. Realizou-se o inventário de um hectare considerando todas as árvores com circunferência a altura do peito (CAP) ≥ 30 cm. Estas foram identificadas e medidas suas alturas totais e comerciais. O método de Área Fixa adotado foi o de faixas com 100 m de comprimento e 10 m de largura (10 faixas contíguas). Para os métodos de Prodan, Quadrantes e Bitterlich foram realizados 25 pontos amostrais distribuídos sistematicamente a cada 20 m e do método de Strand realizou-se 30 linhas de amostragem de 15,7 m de comprimento. Pela análise de variância verificou-se que os distintos métodos não apresentaram diferenças significativas na estimativa do volume, área basal e número de árvores por hectare. Encontrou-se diferença significativa no número de espécies amostradas, sendo o método de Área Fixa o que apresentou maior média. Com os tempos tomados e os coeficientes de variação encontrados para cada estimativa foi calculada a eficiência relativa, onde verificou-se que, o método de Strand foi sempre superior aos demais métodos na estimação de todos os parâmetros. Em contraposição, o método dos Quadrantes foi o que apresentou a menor eficiência relativa na estimação de todos os parâmetros.

Crecimiento y rendimiento del pino hondureno sin entresacar

A base de sobrevivencia, crecimiento y rendimiento, se evaluó el espaciamiento, sin entresacar, de pino hondureno (Pinus caribaea var. hondurensis Morelet) con edades de 23.3 a 25 años en cuatro rodales en Puerto Rico. Los resultados demostraron diferencias significativamente marcadas entre los promedios de sobrevivencia, diámetro y altura de árboles en rodales con espaciamientos que fluctuaron desde 1.5 x 1.5 m a 4.3 x 4.3 m. Sin embargo, debido a la disminución de crecimiento en diámetro y altura y al aumento en la mortalidad en los rodales de espaciamientos más estrechos (1.5 m y 2.1 m), y al crecimiento rápido en diámetro en los rodales con espaciamientos más anchos (3.0 m y 4.3 m), no hubo diferencias significativas entre tratamientos en área basal, volumen total bajo la corteza y promedio de incremento de volumen anual. Se recomiendan espaciamientos anchos en plantaciones donde no sean posibles los entresaques tempranos.

Estimation of Bole Surface Area and Bark Volume with Monte Carlo Methods

Many attributes of forest trees can be regarded as integrals of some continuous-dimensional characteristic, and thus their estimation is amenable to variance reduction sampling strategies that have been devised and developed in the simulation field. For the estimation of tree characteristics, these methods provide alternatives to the usual estimation by a fitted regression, and in addition, they provide a flexibility to estimate the integral between any two heights on the tree bole. The application of these methods to the estimation of bole surface area and bark volume is explained, and practical aspects of implementation are discussed.

A Growth and Yield Model for Improved Eastern Cottonwood Plantations in the Lower Mississippi Delta

Abstract A compatible growth and yield model was developed based on remeasurement data collected from 183 plots on unthinned improved eastern cottonwood (Populus deltoides Bartr.) plantations in the lower Mississippi Delta. The Sullivan and Clutter (1972) equation form was selected for predicting cubic-foot volume yield and projecting volume from site index and initial age and basal area. Yield equations explained 97% and 94%, respectively, of the variations in total outside bark and merchantable inside bark volumes. Mean annual increment of merchantable volume culminated between 8 and 15 years, depending on site index and initial basal area. South. J. Appl. For. 15(4):213-216.

Bark Thickness and Bark Volume in Southwestern Oregon Douglas-Fir

Abstract A segmented polynomial taper equation for southwestern Oregon Douglas-fir (Pseudotsuga menziesii) predicts double bark thickness (dbt) at any point above breast height. Below breast height predictions assume conformity to a neiloid frustrum. The equations facilitate estimation of inside bark diameter (dib) given outside bark (dob) measurements. Bark volume and bark biomass can also be estimated when supplemented with existing dib taper equations developed for southwestern Oregon. West J. Appl. For. 5(1):5-8.

INSECTICIDE RESIDUES ON PINE BARK: INFLUENCE OF TREES, SAMPLE VOLUME AND SIZE ON VARIABILITY1

Residues of carbaryl (Sevimol®) in ponderosa pine bark were quantified by gas chromatography and the major sources of experimental error were determined. Quantification of carbaryl residues was significantly affected by between-tree variation and disc size (bark volume). Variation between trees had the greatest effect on residue estimates. Mean carbaryl residues for all trees ranged from 241 μg/g of bark to 1418 μg/g of bark. Nonsignificant tree-disc size interactions indicated that residue levels were fairly consistent within trees. Prediction curves were constructed to project levels of precision for combinations of discs and trees.

Loblolly Pine (Pinus taeda) Response to Weed Control in Central Louisiana

Herbaceous weed control was studied on a loblolly pine planting site in central Louisiana. Pine growth was enhanced without eradicating weeds; reducing weed biomass about 50% increased the mean inside bark volume of loblolly pine saplings 53% on the weeded treatments compared to the untreated control after five growing seasons in the field. Pines receiving both preplant weed control with glyphosate or disking and postplant weed control with a series of yearly treatments (1982, atrazine plus simazine; 1983, atrazine plus oxyfluorfen; 1984, hexazinone; and 1985, hexazinone) had 62% greater volume than pines on the preplant-only treatments. So, the best gains in loblolly pine volume required postplant weed control.

Response of planted Pinus taeda L. to brush control in Northern Louisana

Eradication of brush, defined as hardwood trees, shrubs, blackberries, vines, and volunteer pines, was not necessary to maximize juvenile pine growth in northern Louisiana Pinus taeda L. plantations. Pine height and diameter gains were similar on treatments when either (1) only the above ground portion of the brush was cut yearly or (2) both the above ground stems and root systems of brush species were controlled each year. At age 10, planted pines on both treatments averaged 0.9 m taller with a 2.5 cm greater stem diameter at breast height (1.4 m) than those on untreated checks. Total outside bark volume per pine averaged 51.9 dm 3 on checks vs 78.5 dm 3 on treated plots.

Interception storage capacities of tropical rainforest canopy trees

Abstract The rainwater interception storage capacities of mature canopy trees in a tropical rainforest site in northeast Queensland, Australia, were approximated using a combination of field and laboratory measurements. The above-ground vegetative surfaces of five selected species (three flaky-barked; two smooth-barked) were saturated under laboratory conditions in order to establish their maximum interception storage capacities. Average leaf surface interception storages ranged from 112 to 161 ml m−2. The interception storages of bark ranged from 0.51 to 0.97 ml cm−3. These standardized interception storages were applied to estimates of leaf surface area and bark volume for 51 mature canopy trees representing the selected species in the field site. The average whole tree interception storage capacities of the five species ranged from 110 to 5281 per tree and 2.2 to 8.3 mm per unit projected crown area. The highly significant interspecific differences in interception storage capacity suggest that both floristic and demographic data are needed in order to accurately calculate a forest-wide interception storage capacity for species-rich tropical rainforest vegetation. Species with large woody surface areas and small projected crown areas are capable of storing the greatest depth equivalents of rainwater under heavy rainfall conditions. In the case of both the flaky-barked and the smooth-barked species, bark accounted for > 50% of the total interception storage capacity under still-air conditions, and > 80% under turbulent air conditions. The emphasis in past interception studies on the role of leaf surfaces in determining the interception storage capacity of a vegetative cover must be modified for tropical rainforests to include the storage capacity provided by the bark tissue on canopy trees.