scholarly journals Evaluacion De Dos Instrumentos De Medicion En La Determinación Del Área Basal En Pinus Radiata

2017 ◽  
Vol 13 (24) ◽  
pp. 10
Author(s):  
Norma Lara Vásconez ◽  
Janneth Morocho ◽  
Santiago Lara ◽  
Oscar Guadalupe ◽  
Keilly Chavez ◽  
...  
Keyword(s):  
Pinus Radiata ◽  
Forest Inventory ◽  
Basal Area ◽  
Measuring Instruments ◽  
Cross Sectional ◽  
Stand Volume ◽  
Breast Height ◽  
Measurement Tools ◽  
Pine Trees ◽  
Parallel Measurement

This study compares the diameter of data obtained from utilizing two measuring instruments (the caliper and diameter tape). This instrument is the two most commonly used instruments for measuring tree diameters in forest inventory procedures. The measurement of diameter has a high implication in the estimation of the basal area and stand volume. It is therefore imperative to ensure accurate measurement of the diameter of trees in a stand. This work evaluated data taken with these two diameter measuring instruments. In order to evaluate the performance of the measuring instruments, parallel measurement of the diameter at breast height (DBH) of a sample of Pinus radiata trees in a plantation were measured. Also, the basal area of the stand was determined for both instruments. It was concluded through the analysis of variance (ANOVA) that there is no significant (p =0.958) difference between the averages of the calculated basal areas from the diameter measurements obtained by the diameter tape and the caliper. The estimated value from the diameter tape was 0,04190829, while the caliper was 0,04145599. Thus, the use of the two measurement tools led to similar results in the calculation of the cross-sectional areas of pine trees measured at breast height.

scholarly journals Relative effects of dendrometers on the estimation of diameter at breast height, stand basal area and stand volume in uneven-aged northern hardwoods

2009 ◽  
Vol 85 (3) ◽  
pp. 446-452 ◽  
Author(s):  
François Guillemette ◽  
Marie-Claude Lambert
Keyword(s):  
Basal Area ◽  
Major Axis ◽  
Minor Axis ◽  
Northern Hardwoods ◽  
Parameter Estimates ◽  
Betula Alleghaniensis ◽  
Stand Volume ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Stand Basal Area

Four methods of estimating diameter at breast height (DBH) were used on 558 northern hardwood stems, located in 6, 0.25-ha plots, to compare their effects. The first method was a diameter tape reading and the second was a systematic reading, along a predefined axis, taken with a calliper. The last 2 methods were both obtained from the arithmetic mean of 2 different pairs of calliper readings taken at right angles. The first pair was directed along the major bole axis and the other pair along the minor axis. The 4 methods were compared in terms of mean tree diameter, plot basal area and plot volume. There were significant differences (p < 0.05) in parameter estimates among methods, and the differences varied according to species (Acer saccharum Marsh. and Betula alleghaniensis Britt.) and tree size class. Differences among methods were more evident for larger DBH classes, which contribute most to the significant differences observed for both the plot and stand basal area and volume. Overall, tree DBH, plot basal area and plot volume provided by these 4 methods ranked in this ascending order: mean calliper reading directed along the minor axis, systematic calliper reading, mean calliper reading directed along the major axis, and diameter tape. The difference in stand basal area or volume between the estimates obtained with a systematic calliper reading and a diameter tape was 1.1 m2/ha with a mean basal area of about 21 m2/ha, or 10.5 m3/ha with a mean stand volume of 169 m3/ha. Because of the magnitude of these differences, it is recommended the method of DBH estimation be specified in studies, to be careful when crossing databases or models using different methods of DBH estimation, and to always maintain the same method of DBH estimation when remeasuring a plot. Key words: northern hardwoods, dendrometer, diameter tape, calliper, caliper, DBH measurement, basal area, volume

scholarly journals Diameter increment distribution along the stem of narrow-leaved ash in response to thinning intensity

2019 ◽  
Vol 143 (1-2) ◽  
pp. 45-51
Author(s):  
Ali Kemal Özbayram
Keyword(s):  
Rapid Development ◽  
Basal Area ◽  
Cross Sectional ◽  
Thinning Intensity ◽  
Tree Diameter ◽  
Diameter Increment ◽  
Breast Height ◽  
Sample Tree ◽  
Fraxinus Angustifolia ◽  
Different Parts

Narrow-leaved ash (NLA, Fraxinus angustifolia) is an important tree species due to its rapid development and valuable wood. In the pure NLA plantations in Turkey, little is known about the effects of thinning intensity on the diameter increment of different parts of the tree stem. In 2005, a thinning experiment with three thinning intensities (control: 0%; moderate: 19%; heavy: 28% of basal area removed) was established in an NLA plantation in Sakarya, Turkey. Seven years after thinning, a total of 25 sample trees representing dominant and co-dominant trees were felled, and cross-sectional stem samples were taken for analysis. The diameter at breast height (d<sub>1.30</sub>) and d<sub>1.30</sub> increments of the co-dominant trees with the moderate and heavy treatments were similar to each other and greater than in the controls. The seven-year d<sub>1.30</sub> increments of the dominant trees in the heavy-treatment plot were approximately 20% greater than in the other treatments plots. The highest diameter increments in both dominant and co-dominant trees for all treatments were determined at the 0.30 m and 17.30 m section heights. The sample tree diameter increments of between 1.30 m and 13.30 m were similar within their classes. In conclusion, heavy-intensity thinning of up to 28% did not cause tapering in the NLA plantation stems, and thus, heavy thinning can be recommended for NLA trees.

scholarly journals An individual-tree linear mixed-effects model for predicting the basal area increment of major forest species in Southern Europe

2020 ◽  
Vol 29 (3) ◽  
pp. e019
Author(s):  
Lucio Di Cosmo ◽  
Diego Giuliani ◽  
Maria Michela Dickson ◽  
Patrizia Gasparini
Keyword(s):  
Forest Inventory ◽  
Basal Area ◽  
Ordinary Least Squares ◽  
Mixed Effects ◽  
Forest Growth ◽  
Mixed Effects Model ◽  
Basal Area Increment ◽  
Individual Tree ◽  
Diameter At Breast Height ◽  
Breast Height

Aims of the study. Assessment of growth is essential to support sustainability of forest management and forest policies. The objective of the study was to develop a species-specific model to predict the annual increment of tree basal area through variables recorded by forest surveys, to assess forest growth directly or in the context of more complex forest growth and yield simulation models.Area of the study. Italy.Material and methods. Data on 34638 trees of 31 different forest species collected in 5162 plots of the Italian National Forest Inventory were used; the data were recorded between 2004 and 2006. To account for the hierarchical structure of the data due to trees nested within plots, a two-level mixed-effects modelling approach was used.Main results. The final result is an individual-tree linear mixed-effects model with species as dummy variables. Tree size is the main predictor, but the model also integrates geographical and topographic predictors and includes competition. The model fitting is good (McFadden’s Pseudo-R2 0.536), and the variance of the random effect at the plot level is significant (intra-class correlation coefficient 0.512). Compared to the ordinary least squares regression, the mixed-effects model allowed reducing the mean absolute error of estimates in the plots by 64.5% in average.Research highlights. A single tree-level model for predicting the basal area increment of different species was developed using forest inventory data. The data used for the modelling cover 31 species and a great variety of growing conditions, and the model seems suitable to be applied in the wider context of Southern Europe.   Keywords: Tree growth; forest growth modelling; forest inventory; hierarchical data structure; Italy.Abbreviations used: BA - basal area; BAI – five-year periodic basal area increment; BALT - basal area of trees larger than the subject tree; BASPratio - ratio of subject tree species basal area to stand basal area; BASTratio - ratio of subject tree basal area to stand basal area; CRATIO - crown ratio; DBH – diameter at breast height ; DBH0– diameter at breast height corresponding to five years before the survey year; DBHt– diameter at breast height measured in the survey year; DI5 - five-year, inside bark, DBH increment; HDOM - dominant height; LULUCF - Land Use, Land Use Changes and Forestry; ME - mean error; MAE - mean absolute error; MPD - mean percent deviation; MPSE - mean percent standard error; NFI(s) - National Forest Inventory/ies; OLS - ordinary least squares regression; RMSE - root mean squared error; UNFCCC - United Nation Framework Convention on Climate Change.

Use of Small Plots Can Overestimate Upper Limits to Basal Area and Biomass

1975 ◽  
Vol 5 (3) ◽  
pp. 503-505 ◽  
Author(s):  
J. Harry G. Smith
Keyword(s):  
Unit Area ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Subalpine Fir ◽  
Good Relationship ◽  
Breast Height ◽  
Plot Size ◽  
Upper Limits

Measurements of cross-sectional area outside bark at breast height in a spruce – subalpine fir forest were studied to determine the effects of plot size on minimum and maximum amounts of basal area sampled per unit area. Assuming a good relationship between basal area and biomass of trees, the need for careful interpretation of stand weight estimates on small plots is illustrated.

Development of Norway spruce dominated stands after single-tree selection and low thinning

2002 ◽  
Vol 32 (9) ◽  
pp. 1577-1584 ◽  
Author(s):  
Erkki Lähde ◽  
Olavi Laiho ◽  
Yrjö Norokorpi ◽  
Timo Saksa
Keyword(s):  
Norway Spruce ◽  
Basal Area ◽  
P Values ◽  
Stand Volume ◽  
Single Tree ◽  
Breast Height ◽  
Single Tree Selection ◽  
Annual Volume ◽  
Mineral Soils ◽  
Site Types

The study included 23 stands (at least 2 ha each in size) distributed from southern to northern Finland. These Norway spruce (Picea abies (L.) Karst.) dominated stands grew on fertile (Oxalis–Myrtillus and Myrtillus site types) mineral soils. Each stand contained two substands randomly treated with single-tree selection or low thinning. The harvested volumes (trees > 9 cm) varied greatly but averaged 94 m3·ha–1 in the former consisting of mainly medium-sized and larger (>15 cm) trees and 68 m3·ha–1 in the latter of mainly medium-sized and smaller (<15 cm) trees. After treatment, mean diameter at breast height (DBH), basal area, and stand volume were 12–17% lower in single-tree selection than in low thinning. The stem distributions were reverse-J shaped and bell shaped, respectively. During the monitoring of a mean of 11 years, about one cutting cycle in single-tree selection, stand volume (trees > 9 cm) increased 38% in single-tree selection and 27% in low thinning. The respective current annual volume and relative increments were 5.4 (3.6%) and 4.6 m3·ha–1·year–1 (2.4%). In 18 (volume) and in 22 (relative) of the 23 plot pairs the increment was higher after single-tree selection than after low thinning (p values 0.013 and <0.001, respectively). Single-tree selection plots additionally included 1300 saplings/ha (from breast height to DBH 9 cm) after cutting, with the transition of 80 saplings/ha into larger trees and with the ingrowth, mainly spruce, of 170 seedlings/ha into saplings during monitoring.

Thinning and nitrogen fertilization effects on sapwood development and relationships of foliage quantity to sapwood area and basal area in Douglas-fir

1983 ◽  
Vol 13 (3) ◽  
pp. 384-389 ◽  
Author(s):  
H. Brix ◽  
A. K. Mitchell
Keyword(s):  
Nitrogen Fertilization ◽  
Basal Area ◽  
Douglas Fir ◽  
Annual Rings ◽  
Cross Sectional ◽  
Sapwood Area ◽  
Breast Height ◽  
Linear Relationships ◽  
Regression Slopes ◽  
Fertilization Effects

A 24-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was treated with various levels and combinations of nitrogen fertilization and thinning. Over a period of 5–9 years after treatments, trees were sampled to determine effects on foliage quantity and sapwood characteristics at different stem heights together with their relationships. Sapwood width remained relatively constant up the stem where heartwood was present, but the number of annual rings it contained decreased with height. The sapwood width at breast height (bh) increased with stem diameter; treatments had little effect on percent sapwood at bh. The ratio of foliage mass to sapwood cross-sectional area changed for different portions of the crown and was lower when based on sapwood area at bh than at base of live crown. Significant linear relationships of foliage mass and area to sapwood area at bh were found, but relationships of foliage to basal area (bh) were just as close for all treatments; treatments significantly affected these relationships with control trees having the lowest regression slopes.

scholarly journals COMPARAÇÃO DE MÉTODOS DE AMOSTRAGEM EM FRAGMENTOS DE FLORESTA OMBRÓFILA MISTA, EM LEBON RÉGIS, SC

FLORESTA ◽  
2014 ◽  
Vol 44 (3) ◽  
pp. 393
Author(s):  
Saulo Jorge Téo ◽  
Chaiane Rodrigues Schneider ◽  
Luan Demarco Fiorentin ◽  
Reinaldo Hoinacki da Costa
Keyword(s):  
Forest Inventory ◽  
Relative Efficiency ◽  
Sampling Methods ◽  
Statistical Significance ◽  
Basal Area ◽  
Simple Random Sampling ◽  
The Other ◽  
Forest Fragments ◽  
Breast Height ◽  
Fixed Area

O objetivo desta pesquisa foi avaliar e comparar métodos de amostragem de Área Fixa, Bitterlich, Strand e Prodan em fragmentos de Floresta Ombrófila Mista em Lebon Régis, SC. O processo de amostragem utilizada foi aleatória simples. Em cada unidade amostral, foram avaliadas todas as árvores de diâmetro à altura do peito maior ou igual a 5 cm. Para o método de Área Fixa, utilizou-se dimensões 10 x 50 m (500 m²); para Bitterlich e Strand, adotou-se Fator de Área Basal igual a 2; e para Prodan, foram avaliadas as 6 árvores mais próximas. Apenas o método de amostragem da Área Fixa apresentou suficiência amostral, porém também apresentou o maior tempo de execução no campo, com resultados significativamente diferentes dos demais. Já a eficiência relativa apresentou-se maior para o método de Strand, porém sem diferença estatística significativa com relação aos demais. Não houve diferenças significativas entre o número de árvores e área basal por hectare, estimados pelos diferentes métodos de amostragem.Palavras-chave: Inventário Florestal; eficiência relativa; floresta com araucária. AbstractComparison of sampling methods in Mixed Ombrophyllous Forest fragments, in Lebon Régis - SC. The objective of this research was to evaluate and compare sampling methods Fixed Area, Bitterlich, Strand and Prodan, in fragments of Mixed Ombrophyllous Forest, in Lebon Régis, SC state, Brazil. The forest inventory applies a simple random sampling. At each sampling unit, we evaluated every tree with diameter at breast height greater than or equal to 5 cm. For the method of Fixed Area we used dimensions of 10 x 50 m (500 m²), for Bitterlich and Strand we adopted Basal Area Factor equal to 2, and for Prodan we evaluated the 6 nearest trees. Only the Fixed Area method presented sampling sufficiency, however, it presented highest execution time in the field as well, with results significantly different from the other sampling methods. The relative efficiency was higher for Strand, but without statistical significance compare to the other methods. There were no significant differences between the number of trees and basal area per hectare, estimated by the different sampling methods.Keywords: Forest inventory; relative efficiency; araucaria forest. 

The Prediction of Heartwood Diameter in Radiata Pine Trees

1974 ◽  
Vol 4 (4) ◽  
pp. 524-529 ◽  
Author(s):  
W. E. Hillis ◽  
Nell Ditchburne
Keyword(s):  
Radiata Pine ◽  
Regression Equation ◽  
Tree Age ◽  
Cross Sectional ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
Pine Trees ◽  
High Degree ◽  
Heartwood Diameter ◽  
Different Parts

Cross-sectional characteristics of Pinusradiata trees grown in different parts of Australia were examined. A regression equation which related heartwood diameter at a given age of the tree to the diameter at breast height outside bark and the product of the tree age and its diameter at 5 years gave a high degree of correspondence between observed and predicted heartwood diameter.

scholarly journals Personal Bias in Forest Measurements

1980 ◽  
Vol 56 (5) ◽  
pp. 222-224 ◽  
Author(s):  
Stephen A. Y. Omule
Keyword(s):  
Coefficient Of Variation ◽  
Forest Inventory ◽  
Measurement Errors ◽  
Total Error ◽  
Basal Area ◽  
Percentage Error ◽  
Probability Level ◽  
Tree Diameter ◽  
Breast Height ◽  
Personal Bias

The assumption that measurement errors are negligible during a forest inventory was tested using forestry students. The magnitude of personal bias in measuring tree diameter at breast height (dbh), total height, and basal area per hectare was obtained. Bias was negligible in dbh measurements and the among-crew coefficient of variation (CV) was 8.16%. Heights were significantly underestimated and the among-crew CV was 21.86%. The percentage error in basal area per hectare determination was 4.09% at the 95% probability level, using a prism of basal area factor 6. Measurement errors are, in general, not negligible. Their magnitude should be estimated per inventory and included in the total error of the inventory estimate.

APLIKASI SCORE CARD UNTUK PENILAIAN KINERJA PENGELOLAAN SUNGAI

Kinerja ◽  
2019 ◽  
Vol 1 (02) ◽  
pp. 38-51
Author(s):  
Anis Lutfiati
Keyword(s):  
Monitoring And Evaluation ◽  
Planning System ◽  
Performance Measurement System ◽  
Measuring Instruments ◽  
Evaluation Activity ◽  
Executive Performance ◽  
Balance Score Card ◽  
Score Card ◽  
Measurement Tools ◽  
Early Use

Evaluation activity should basically clear and provide context for the improvement ofmanagement processes for the better future . This should be realized by every management withinthe company wherever located . Clarity measurement tools will help achieve the objectives of thecompany later . One of the measuring instruments are applied is BSC (Balance Score Card ).BSC Assist management to evaluate and help correct the exact performance of the company.At first , the BSC is used to improve executive performance measurement system. Early use of theexecutive's performance is measured only in terms of finances. Then developed into a morespacious with four perspectives, which are then used to measure the performance of theorganization as a whole . The four perspectives, namely financial, customer, internal businessprocesses and learning and growth .In the development of the BSC has helped many companies to successfully achieve its goals. BSChas several advantages that are not owned traditional systems management strategy. Theadvantages of the BSC approach in the strategic planning system is able to produce a strategicplan, which has the characteristics : a comprehensive, coherent, balanced and measured .Basin , is an area that needs attention . Governments and communities must work together toachieve clean rivers, healthy, and productive and provide sustainable benefits to the surroundingcommunity. If the indicators are assessed in the score card is identical to the indicators used inthe monitoring and evaluation of the basin, the score card is also a tool for monitoring andevaluation of the river basin

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