scholarly journals Semi-empirical estimation of log taper using stem profile equations

2021 ◽  
Vol 67 (No. 7) ◽  
pp. 318-327
Author(s):  
Andrii Bilous ◽  
Viktor Myroniuk ◽  
Viktor Svynchuk ◽  
Oleksandr Soshenskyi ◽  
Oleksandr Lesnik ◽  
...  
Keyword(s):  
Tree Species ◽  
Volume Estimation ◽  
Empirical Estimation ◽  
Stem Form ◽  
Wood Volume ◽  
Round Wood ◽  
European Standards ◽  
Taper Equation ◽  
Annual Distribution ◽  
Semi Empirical

In January 2019 the forest industry in Ukraine adopted European standards for measuring and grading of round wood based on mid-point diameters, which caused major discrepancies from traditionally used estimates of timber volume using top diameters. To compare methods of merchantable wood volume estimation, we investigated the stem form inside bark for two dominant tree species in Ukraine, i.e. Scots pine (Pinus sylvestris L.) and common oak (Quercus robur L.). We used tree stem measurements to fit stem profile equations, whereas simulation was applied to derive log taper. We found that Newnham's (1992) variable-exponent taper equation performed well for predicting stem taper for both tree species. Then, we simulated the structure of harvested wood, so that it replicated annual distribution of logs by their length and diameters. As a result, the average log taper was estimated at 0.836 ÷ 0.855 cm·m<sup>–1</sup> and 1.180 ÷ 0.121 cm·m<sup>–1</sup> for pine and oak, respectively. The study also indicated that log taper varied along stems. The higher rates of diameter decrease were found for butt logs, for which the taper was 2.5–3.5 times higher than its average for the whole stem. The results of our study ensure the stacked round wood volume conversion between estimates obtained using top and mid-point diameters.

scholarly journals Taper Equations for Five Major Commercial Tree Species in Manitoba, Canada

2007 ◽  
Vol 22 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Ryan J. Klos ◽  
G. Geoff Wang ◽  
Qing-Lai Dang ◽  
Ed W. East
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
White Spruce ◽  
Jack Pine ◽  
Volume Estimation ◽  
Trembling Aspen ◽  
Stem Form ◽  
Taper Equation ◽  
Taper Equations

Abstract Kozak's variable exponent taper equation was fitted for balsam poplar (Populus balsamifera L.), trembling aspen (Populus tremuloides Michx.), white spruce (Picea glauca [Moench] Voss), black spruce (Picea mariana [Mill.] B.S.P.), and jack pine (Pinus banksiana Lamb.) in Manitoba. Stem taper variability between two ecozones (i.e., Boreal Shield and Boreal Plains) were tested using the F-test. Regional differences were observed for trembling aspen, white spruce, and jack pine, and for those species, separate ecozone-specific taper equations were developed. However, the gross total volume estimates using the ecozone-specific equations were different from those of the provincial equations by only 2 percent. Although the regional difference in stem form was marginal within a province, a difference of approximately 7 percent of gross total volume estimation was found when our provincial taper equations were compared with those developed in Alberta and Saskatchewan. These results suggest that stem form variation increases with spatial scale and that a single taper equation for each species may be sufficient for each province.

scholarly journals Stand Stability of Pure and Mixed-Eucalyptus Forests of Different Tree Species in a Typhoon-Prone Area

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 458
Author(s):  
Haiyan Deng ◽  
Linlin Shen ◽  
Jiaqi Yang ◽  
Xiaoyong Mo
Keyword(s):  
Tree Species ◽  
Forest Restoration ◽  
Large Scale ◽  
Stand Structure ◽  
Pinus Elliottii ◽  
Stem Form ◽  
Tree Species Composition ◽  
Eucalyptus Plantation ◽  
Mixed Plantation ◽  
Preservation Rate

Background and Objectives: The stable stand structure of mixed plantations is the basis of giving full play to forest ecological function and benefit. However, the monocultural Eucalyptus plantations with large-scale and successive planting that caused ecological problems such as reduced species diversity and loss of soil nutrients have presented to be unstable and vulnerable, especially in typhoon-prone areas. The objective of this study was to evaluate the nonspatial structure difference and the stand stability of pure and mixed-Eucalyptus forests, to find out the best mixed pattern of Eucalyptus forests with the most stability in typhoon-prone areas. Materials and Methods: In this study, we randomly investigated eight plots of 30 m × 30 m in pure and mixed-Eucalyptus (Eucalyptus urophylla S. T. Blake × E. grandis W. Hill) plantations of different tree species (Neolamarckia cadamba (Roxb.) Bosser, Acacia mangium Willd., and Pinus elliottii var. Elliottii Engelm. × P. caribaea Morelet) on growth status, characterized and compared the distribution of nonspatial structure of the monoculture and mixtures, and evaluated the stand quality and stability from eight indexes of the nonspatial structure, including preservation rate, stand density, height, diameter, stem form, degree of stem inclination, tree-species composition, and age structure. Results: Eucalyptus surviving in the mixed plantation of Eucalyptus and A. mangium (EA) and in the mixed plantation of Eucalyptus and P. elliottii × P. caribaea (EP) were 5.0% and 7.6% greater than those in pure Eucalyptus plantation (EE), respectively, while only the stand preservation rate of EA was greater (+2.9%) than that of the pure Eucalyptus plantation. The proportions of all mixtures in the height class greater than 7 m were fewer than that of EE. The proportions of EA and mixed plantation of Eucalyptus and N. cadamba (EN) in the diameter class greater than 7 m were 10.6% and 7.8%, respectively, more than that of EE. EN had the highest ratio of branching visibly (41.0%), EA had the highest ratio of inclined stems (8.1%), and EP had the most straight and complete stem form (68.7%). The stand stability of the mixed plantation of Eucalyptus and A. mangium presented to be optimal, as its subordinate function value (0.76) and state value (ω = 0.61) of real stand were the largest. Conclusions: A. mangium is a superior tree species to mix with Eucalyptus for a more stable stand structure in the early growth stage to approach an evident and immense stability and resistance, which is of great significance for the forest restoration of Eucalyptus in response to extreme climate and forest management.

scholarly journals Constructing single-entry stem volume models for four economically important tree species of Greece

2021 ◽  
Vol 48 (2) ◽  
pp. 136-146
Author(s):  
Panagiotis P. Koulelis ◽  
Kostas Ioannidis
Keyword(s):  
Tree Species ◽  
National Level ◽  
Sustainable Use ◽  
Information Criterion ◽  
Cost Effective ◽  
Volume Estimation ◽  
Stem Volume ◽  
Nonlinear Regression Models ◽  
Cubic Polynomial ◽  
Two Parameter

Abstract Three different nonlinear regression models were tested for their ability to predict stem volume for economically important native tree species in Greece. Τhe models were evaluated using adjusted R square (Adj Rsqr) root mean square error (RMSE) and Akaike information criterion (AICc), where necessary. In general, the quadratic polynomial and cubic polynomial models and the two-parameter power models fit the data well. Although the two-parameter power function fit best for fir, oak, and beech trees, the cubic polynomial model produced the best fit statistics for black pine. Making forest inventory estimates often involves predicting tree volumes from only the diameter at breast height (DBH) and merchantable height. This study covers important gaps in fast and cost-effective methods for calculating the volume of tree species at national level. However, the increasing need for reliable estimates of inventory components and volume changes requires more accurate volume estimation techniques. Especially when those estimates concern the national inventory, those models must be validated using an entire range of age/diameter and site classes of each species before their extended use across the country to promote the sustainable use of forest resources.

What factors should be accounted for when developing a generalized taper function for black wattle trees?

2020 ◽  
Vol 50 (11) ◽  
pp. 1113-1123
Author(s):  
Mateus Niroh Inoue Sanquetta ◽  
John Paul McTague ◽  
Henrique Ferraço Scolforo ◽  
Alexandre Behling ◽  
Carlos Roberto Sanquetta ◽  
...  
Keyword(s):  
Solid Wood ◽  
Auxiliary Variables ◽  
Stem Form ◽  
Mixed Effect ◽  
Individual Tree ◽  
Taper Function ◽  
Black Wattle ◽  
Taper Equation ◽  
Total Tree ◽  
Mixed Effect Modeling

Taper functions have been widely used for various purposes. Several functions were developed and successfully applied; however, most of these functions fail to account for the influence of stand-level and individual-tree effects of variation on the stem profile. Hence, we aimed in this study to assess how these factors influence the stem profile of black wattle (Acacia mearnsii De Wild.) trees in southern Brazil. There is a notable necessity for developing a domestic market for black wattle solid wood. The database was composed of 218 black wattle trees at age 10 years distributed across the state of Rio Grande do Sul, Brazil. A dimensionally compatible taper equation combined with the mixed-effect modeling approach was used. Additionally, auxiliary variables were included to build a generalized taper function that explains stem form variations. In general, all variables showed a significant influence on the stem profile, except the crown ratio. The inclusion of relative spacing and tree hierarchical position in the taper function resulted in higher accuracy when estimating stem diameters and total tree volume. This study indicates that accounting for attributes at the stand and individual-tree levels may improve stem profile predictions, as well as the biological soundness of the taper function.

A geometrical tree volume model based on the location of the centre of gravity of the bole

1982 ◽  
Vol 12 (2) ◽  
pp. 215-221 ◽  
Author(s):  
Robert R. Forslund
Keyword(s):  
Volume Estimation ◽  
Diameter Measurement ◽  
Stem Form ◽  
Total Height ◽  
Volume Model ◽  
Breast Height ◽  
Centre Of Gravity ◽  
Geometrical Form ◽  
Volume Equation ◽  
Diameter Outside Bark

A tree bole model describing a geometrical form in between a paraboloid and cone "paracone" has been developed. The model is based on empirical evidence that the average centre of gravity of aspen (Populustremuloides Michx.) boles without branches lies at 3/10 of the bole height from its base. Outside bark bole volume, V (cubic decimetres), can therefore be estimated nondestructively from the total height, H (metres), and the diameter outside bark, dK (centimetres), measured at a relative height, K, as follows:[Formula: see text]Based on a sample of 70 aspen stems, this equation estimates individual bole volume from total bole length or height and from a single diameter measurement, either at the 3/10 position or at the breast-height position, as accurately as Smalian's formula using seven diameter measurements. Based on the sample, the 3/10 position should be chosen over breast height wherever breast height lies below 20 or above 60% of the total height. It is important that care be taken in the measurement of the diameter due to the sensitivity of the volume equation to diameter variation. In addition to volume estimation, the paracone model provides a comparison profile around which stem form variation within and among species may be observed.

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