Variable-form taper functions for four Alberta tree species

The variable-form taper function was tested on a data set of 5074 trees, consisting of jack pine (Pinusbanksiana Lamb.), lodgepole pine {Pinuscontorta Dougl.), white spruce (Piceaglauca (Moench) Voss), and trembling aspen (Populustremuloides Michx.), from Alberta. When compared with the results of tests performed on the same data using the variable-exponent function and the segmented polynomial model, the variable-form model was found to be superior (based on residual mean squares) for estimating both upper stem diameter ratios and total stem volumes. The two pine species could be combined and a single taper function used without significant loss of accuracy. Stem form in two of the volume sampling regions was significantly different from that in other regions of the province, but this may have been because the samples were not representative of the two regions. The variable-form function gave accurate and unbiased estimates of both merchantable height and merchantable volume.

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A variable-exponent taper equation

Canadian Journal of Forest Research ◽

10.1139/x88-213 ◽

1988 ◽

Vol 18 (11) ◽

pp. 1363-1368 ◽

Cited By ~ 158

Author(s):

A. Kozak

Keyword(s):

Variable Exponent ◽

Computing Time ◽

Variable Form ◽

Diameter At Breast Height ◽

Breast Height ◽

Taper Function ◽

Taper Equation ◽

Taper Equations ◽

Different Parts

A different approach to fitting taper equations has been developed, which eliminates the necessity of using several functions to predict diameter inside bark at different parts of the stem. The variable form taper function is easy to develop and saves computing time. For the data used in this study, it predicted tree profile as a function of height, diameter at breast height, and height from the ground with less bias than many of the taper-estimating systems found in the literature.

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Soil carbon and nutrient stocks under Scots pine plantations in comparison to European beech forests: a paired-plot study across forests with different management history and precipitation regimes

Forest Ecosystems ◽

10.1186/s40663-021-00330-y ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Marco Diers ◽

Robert Weigel ◽

Heike Culmsee ◽

Christoph Leuschner

Keyword(s):

Scots Pine ◽

Tree Species ◽

European Beech ◽

Organic Layer ◽

Species Identity ◽

Data Set ◽

Nutrient Pools ◽

Total N ◽

Precipitation Regimes ◽

Pine Stands

Abstract Background Organic carbon stored in forest soils (SOC) represents an important element of the global C cycle. It is thought that the C storage capacity of the stable pool can be enhanced by increasing forest productivity, but empirical evidence in support of this assumption from forests differing in tree species and productivity, while stocking on similar substrate, is scarce. Methods We determined the stocks of SOC and macro-nutrients (nitrogen, phosphorus, calcium, potassium and magnesium) in nine paired European beech/Scots pine stands on similar Pleistocene sandy substrates across a precipitation gradient (560–820 mm∙yr− 1) in northern Germany and explored the influence of tree species, forest history, climate, and soil pH on SOC and nutrient pools. Results While the organic layer stored on average about 80% more C under pine than beech, the pools of SOC and total N in the total profile (organic layer plus mineral soil measured to 60 cm and extrapolated to 100 cm) were greater under pine by about 40% and 20%, respectively. This contrasts with a higher annual production of foliar litter and a much higher fine root biomass in beech stands, indicating that soil C sequestration is unrelated to the production of leaf litter and fine roots in these stands on Pleistocene sandy soils. The pools of available P and basic cations tended to be higher under beech. Neither precipitation nor temperature influenced the SOC pool, whereas tree species was a key driver. An extended data set (which included additional pine stands established more recently on former agricultural soil) revealed that, besides tree species identity, forest continuity is an important factor determining the SOC and nutrient pools of these stands. Conclusion We conclude that tree species identity can exert a considerable influence on the stocks of SOC and macronutrients, which may be unrelated to productivity but closely linked to species-specific forest management histories, thus masking weaker climate and soil chemistry effects on pool sizes.

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

Forests ◽

10.3390/f12040458 ◽

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.

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MODELOS DE AFILAMENTO PARA Pinus elliottii EM DIFERENTES IDADES, NA REGIÃO DE CAÇADOR, SC

FLORESTA ◽

10.5380/rf.v43i3.30320 ◽

2013 ◽

Vol 43 (3) ◽

pp. 439 ◽

Cited By ~ 3

Author(s):

Saulo Jorge Téo ◽

Alan Marcon ◽

Tiago Ehlers ◽

Júlio César Bianchi ◽

Adriano Peloso ◽

...

Keyword(s):

Pinus Elliottii ◽

Degree Polynomial ◽

Stem Form ◽

Taper Function ◽

Different Ages ◽

Polynomial Models ◽

Old Trees ◽

Taper Models ◽

Best Estimates

Os objetivos deste trabalho foram ajustar e selecionar modelos de afilamento para estimar diâmetros a várias alturas e volume total, com e sem casca, de árvores de Pinus elliottii Engelm., na região de Caçador, SC, para estudar a forma dos fustes das árvores de diferentes idades. Ao todo, 78 árvores, com idades de 10, 18 e 27 anos, foram abatidas, cubadas rigorosamente e tiveram os seus volumes obtidos por meio do método de Smalian. Os modelos de afilamento testados foram os Polinômios de 2º e de 5º Graus e o Polinômio de Potências Fracionárias de Hradetzky. A função de afilamento que apresentou melhor desempenho para estimar o diâmetro com e sem casca ao longo do fuste das árvores foram baseadas no Polinômio de Potências Fracionárias de Hradetzky, para as idades de 10, 18 e 27 anos. O Polinômio de 2º Grau propiciou as melhores estimativas de volume total com casca para as idades de 10 e 27 anos e de volume total sem casca para as idades de 18 e 27 anos. Já o Polinômio de Potências Fracionárias apresentou melhores estimativas de volume com casca para 18 anos e de volume sem casca para árvores de 10 anos. Os fustes das árvores de Pinus elliottii apresentam melhor forma nas idades mais avançadas. AbstractTaper models for Pinus elliottii, at different ages, in the region of Caçador - SC. The research aims to fit and select taper models in order to estimate diameters at different heights and total volumes, inside and outside bark, of Pinus elliottii Engelm. trees, in the region of Caçador - SC, Brazil, as well as to analyze behavior of stem form for trees at different ages. Altogether, 78 trees at 10, 18 and 27 years of age, had been cut and their volumes obtained by Smalian method. The taper models tested were the 2nd and 5th Degree Polynomial and the Hradetzky Polynomial of Fractioned Potencies. The best performance taper function for estimate diameters inside and outside bark throughout the stem were based on the Hradetzky Polynomial of Fractioned Potencies, for 10, 18 and 27 years of age. The 2nd Degree Polynomial provided the best estimates of outside bark volume for 10 and 27 years of age, and of inside bark volume for 18 and 27 years of age, although the Hradetzky Polynomial presented the best estimates of outside bark volume for 18 years of age and of inside bark volume for 10 years old trees. The stems of the Pinus elliottii trees present better form for the oldest tress.Keywords: Polynomial models; profile models; stem form.

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THE EFFECTS OF SUCCESSIVE THINNINGS ON THE HYPSOMETRIC FUNCTION FOR Pinus oocarpa STANDS

FLORESTA ◽

10.5380/rf.v41i2.21891 ◽

2011 ◽

Vol 41 (2) ◽

Cited By ~ 1

Author(s):

Sebastião Do Amaral Machado ◽

Dalmo Arantes de Barros ◽

José Roberto Soares Scolforo ◽

Fausto Weimar Acerbi Junior

Keyword(s):

Standard Error ◽

Unbiased Estimate ◽

Sao Paulo ◽

Average Height ◽

São Paulo ◽

Data Set ◽

Management Regimes ◽

Pinus Oocarpa ◽

Unbiased Estimates ◽

Multiple Determination

This research aimed to test the hypothesis that successive thinnings mischaracterize the hypsometric function, and that after some thinnings the average height of the plots or of the stand () is an unbiased estimate of the remaining tree heights (hi), that is, ĥi = . The data were obtained from Duraflora S. A. in Agudos, State of São Paulo. This data set came from the measurement of diameters and respective heights of 1,100 trees equitably distributed in 11 different treatments with ages ranging from 5 to 25 years, and number of thinnings varying between 0 (zero) and 6. The Stoffels model, previously fitted to all treatments, was used to observe the behavior of the following factors: coefficient of multiple determination (R²), standard error of estimate in percent (Syx %), distribution of residuals, and the significance of the b0 and b1 coefficients in each one of the equations. After tests it was confirmed the hypothesis that average height is a precise estimate of hi for the oldest treatments with more than 4 thinnings. This means low Syx % and unbiased estimates, that is, good distribution of residuals.Keywords: Hypsometric curves; management regimes; plantations; Pinus oocarpa.ResumoEfeitos de desbastes sucessivos sobre a função hipsométrica em povoamentos de Pinus oocarpa Shiede. Esta pesquisa teve como objetivo testar a hipótese que desbastes sucessivos descaracterizam a função hipsométrica e que após alguns desbastes a altura média da parcela ou do povoamento () é uma boa estimativa das demais alturas (ĥi), isto é, ĥi = . A base de dados utilizada para testar a hipótese formulada proveio de plantios de Pinus oocarpa, pertencentes à empresa Duraflora S.A., situada no município de Agudos, sudoeste do Estado de São Paulo. Esta base consistiu da altura e diâmetro de 1100 árvores distribuídas igualmente em 11 tratamentos, com variação de idades e número de desbastes. Visando atingir aos objetivos, foi primeiramente ajustado o modelo de Stoffels, separadamente para cada um dos 11 tratamentos, com o fim de observar a tendência dos coeficientes de determinação múltiplos (R2), do erro padrão da estimativa em porcentagem (Syx %), a distribuição dos resíduos e a significância dos coeficientes de interseção (b0) e de inclinação (b1) em cada uma das equações. Após proceder as análises conclui-se que a medida que se aumenta o número de desbastes os R² vão se tornando cada vez mais baixos , porém os Syx % foram sempre inferiores a 10%. Palavras-chave: Curva hipsométrica; regimes de manejo; plantações; Pinus oocarpa.

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COMPATIBILITY BETWEEN THE STEM VOLUME AND TAPER EQUATIONS VOLUME FOR BLACK WATTLE TREES

FLORESTA ◽

10.5380/rf.v50i3.63881 ◽

2020 ◽

Vol 50 (3) ◽

pp. 1518

Author(s):

Marcos Behling ◽

Henrique Soares Koehler ◽

Alexandre Behling

Keyword(s):

Traditional Approach ◽

Stem Volume ◽

System Of Equations ◽

Data Set ◽

Taper Function ◽

Black Wattle ◽

Taper Equations ◽

Volume Estimates ◽

Forest Engineering

A system of equations widely used in Forest Engineering by the international community of researchers consists of a combination of a volumetric function and a taper function, with the purpose of making volume estimates compatible. When using the volume function and the taper function in a system, the result of the volume estimated by the two functions should be compatible, meaning that the volume estimated by the volumetric function should not differ from the volume obtained by integrating the taper function. Thus, the purpose of this paper was to develop and present the procedures of a system of equations to make volume estimates from both volume and taper equations compatible, and then compare it to the traditional approach, which is used in forestry companies. The procedures proposed were applied to a data set on the Acacia mearnsii De Wild. (black wattle) at sites where the plantation of this species is concentrated in the state of Rio Grande do Sul. The data set included 343 trees ranging from 5 to 10.75 years of age. It was noted that the lack of volume compatibility, in absolute terms, grows exponentially with the size of the tree. The quality of the estimates using the system of compatible equations did not differ from those obtained from the traditional model, therefore, the former is preferable. Furthermore, it was noted that the residuals from the volume and taper equations are correlated, which suggests that the system of equations be fitted simultaneously.

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Estimation of Forest Growing Stock Volume with UAV Laser Scanning Data: Can It Be Done without Field Data?

Remote Sensing ◽

10.3390/rs12081245 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1245 ◽

Cited By ~ 5

Author(s):

Stefano Puliti ◽

Johannes Breidenbach ◽

Rasmus Astrup

Keyword(s):

Tree Species ◽

Laser Scanning ◽

Field Data ◽

Image Data ◽

Visual Assessment ◽

Average Density ◽

Data Set ◽

Tree Crowns ◽

Growing Stock ◽

Stock Volume

Laser scanning data from unmanned aerial vehicles (UAV-LS) offer new opportunities to estimate forest growing stock volume ( V ) exclusively based on the UAV-LS data. We propose a method to measure tree attributes and using these measurements to estimate V without the use of field data for calibration. The method consists of five steps: i) Using UAV-LS data, tree crowns are automatically identified and segmented wall-to-wall. ii) From all detected tree crowns, a sample is taken where diameter at breast height (DBH) can be recorded reliably as determined by visual assessment in the UAV-LS data. iii) Another sample of crowns is taken where tree species were identifiable from UAV image data. iv) DBH and tree species models are fit using the samples and applied to all detected tree crowns. v) Single tree volumes are predicted with existing allometric models using predicted species and DBH, and height directly obtained from UAV-LS. The method was applied to a Riegl-VUX data set with an average density of 1130 points m−2 and 3 cm orthomosaic acquired over an 8.8 ha managed boreal forest. The volumes of the identified trees were aggregated to estimate plot-, stand-, and forest-level volumes which were validated using 58 independently measured field plots. The root-mean-square deviance ( R M S D % ) decreased when increasing the spatial scale from the plot (32.2%) to stand (27.1%) and forest level (3.5%). The accuracy of the UAV-LS estimates varied given forest structure and was highest in open pine stands and lowest in dense birch or spruce stands. On the forest level, the estimates based on UAV-LS data were well within the 95% confidence interval of the intense field survey estimate, and both estimates had a similar precision. While the results are encouraging for further use of UAV-LS in the context of fully airborne forest inventories, future studies should confirm our findings in a variety of forest types and conditions.

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

Canadian Journal of Forest Research ◽

10.1139/cjfr-2020-0163 ◽

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.

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A new method for capturing stem taper variation for trees of diverse morphological types

Canadian Journal of Forest Research ◽

10.1139/cjfr-2016-0018 ◽

2016 ◽

Vol 46 (6) ◽

pp. 804-815 ◽

Cited By ~ 11

Author(s):

David W. MacFarlane ◽

Aaron R. Weiskittel

Keyword(s):

Tree Level ◽

Ecosystem Structure ◽

Stem Form ◽

Data Set ◽

Tree Form ◽

Large Tree ◽

Stem Taper ◽

Type Classes ◽

New Form ◽

Form Type

Understanding variation in tree stem form is fundamental to both ecological and economic assessments of forest ecosystem structure and function. Stem taper models (STMs) are widely used to describe tree form, but it can be challenging to apply them to trees with stems that diverge from an idealized norm, often leading to the exclusion of many trees from stem taper studies. Here, new “whole-tree” form type classes are advanced as simple and useful groupings for capturing stem form variation of trees of diverse morphological types and tested with a large tree data set without exclusion criteria. New form type classes explained much more of main stem form variation than knowledge of tree species, while “merchantable” form types explained the most variation between trees and stands. Broad-leaved species were much more likely to have complex stem forms than needle-leaved species, but species “evergreenness” was a very weak predictor of stem form variation when tree- and stand-level form variation was accounted for. A new, generalized framework for stem taper modeling is demonstrated, using both species and merchantable form types to capture tree-level random effects. New form types and the STM approach are relatively easy to apply and should be relatively simple to integrate into any conventional forest inventory system. Overall, the study demonstrates the importance of including and accounting for the diversity of observed stem forms in developing STMs.

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Why is the Tuaheni Landslide Complex a spreading failure?

10.5194/egusphere-egu2020-18710 ◽

2020 ◽

Author(s):

Morelia Urlaub ◽

Jon Carey ◽

Gareth Crutchley ◽

Joshu Mountjoy

Keyword(s):

Numerical Models ◽

Significant Loss ◽

Data Set ◽

Movement Rates ◽

Novel Approach ◽

Stable Slope ◽

Dynamic Experiments ◽

Direction Of Movement ◽

Set Up ◽

Undrained Loading

<p>Numerous subaqueous landslides exhibit spreading failure morphologies which are typically characterized by repetitive patterns of parallel ridges and troughs oriented perpendicular to the direction of movement. Whilst these spreading failures are commonly attributed to (i) downslope removal of material causing unloading of the temporary stable slope or (ii) significant loss of shear strength of the substratum allowing blocks of overlying sediment to detach and slide downslope, their movement rates and potential triggers remain poorly constrained. Spreading appears to be a dominant failure mechanism within the Tuaheni Landslide Complex (TLC) on the Hikurangi Subduction Margin off the coast of Gisborne, New Zealand. A combination of swath bathymetric, 2D and 3D seismic data, drilling investigations and laboratory experiments on sediments recovered from the TLC indicate that this geomorphology has been generated by translational failure. Failure could occur through episodic cycles of movement-arrest in response to either elevated pore fluid pressures or undrained loading during earthquakes. We developed numerical models that integrate this unique data set to explore the processes that lead to spreading failure and determine how large shear strains can be accommodated without accelerating to catastrophic failure. The results provide a novel approach that demonstrates how seafloor morphology can, in part, be controlled by the underlying failure processes</p>

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