scholarly journals Allocation of oaks to Kraft classes based on linear and nonlinear kernel discriminant variables

2016 ◽  
Vol 53 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Bogna Zawieja ◽  
Katarzyna Kaźmierczak

SummaryA method of discriminant variable determination was used to visualize the division of oak trees into Kraft classes. Usual discriminant variables and several types of kernel discriminant variables were studied. For this purpose the traits of oak (Quercus L.) trees, measured on standing trees, were used. These traits included height of tree, breast height diameter and crown projection area. The use of the Gaussian kernel and modified Gaussian kernel enabled the clearest division into Kraft classes. In particular, the latter method proved to be the most effective.

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Krzysztof Turczański ◽  
Bogna Zawieja ◽  
Tomasz Najgrakowski ◽  
Katarzyna Kaźmierczak

The crown class assessment is a key element in forestry practice. It is a traditional method that finds application in thinning plans, assessment of site index, tree competition, or crown condition. Assigning trees into a given class is done during field surveys and requires precision and experience to avoid inaccuracy. Therefore, Kraft’s system has often been criticized and modified. Thus, in our study, we aimed to analyse whether the directly measured traits of trunk and crown of oak trees (Quercus robur L.) can be applied to crown class assessment. For this purpose, we used the principal component analysis (PCA) and nonlinear kernel principal component analysis (KPCA) based on measurable traits of trunk and crown, i.e., the height of the tree, the diameter at breast height, the length of the crown, and the field crown projection area. In total, we measured 286 mature trees in three oak stands located in western Poland. Results indicate that all chosen traits of trunk and crown allowed, though not always perfect, to assign the trees into given crown classes. The greatest contribution to crown class distinction had the diameter at breast height and the parameters of crown, i.e., and the field crown projection area. Furthermore, results show that the best method of assigning the trees into biosocial classes is the KPCA Gauss, considering the percentage explanation of the total variability, and KPCA Laplace, considering the visual division. In the latter, the multivariate analysis resulted in a similar crown class assignment as the field-assigned method. However, its application requires measurements that make it neither cheaper nor faster than a traditional crown class assessment. It indicates that a traditional field-assigned method, despite its subjectivity, should continue to be of great importance in forestry practice. Moreover, the alternative traits of trunk and crown can be a potentially useful statistical substitute for crown class assessment. Keywords: crown class, oak stand, trunk and crown traits, multivariate methods


2016 ◽  
Vol 58 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Katarzyna Kaźmierczak ◽  
Bogna Zawieja

AbstractThe paper presents an attempt to apply measurable traits of a tree – crown projection area, crown length, diameter at breast height and tree height for classification of 135-year-old oak (QuercusL.) trees into Kraft classes. Statistical multivariate analysis was applied to reach the aim. Empirical material was collected on sample plot area of 0.75 ha, located in 135-year-old oak stand. Analysis of dimensional traits of oaks from 135-year-old stand allows quite certain classification of trees into three groups: pre-dominant, dominant and co-dominant and dominated ones. This seems to be quite promising, providing a tool for the approximation of the biosocial position of tree with no need for assessment in forest. Applied analyses do not allow distinguishing trees belonging to II and III Kraft classes. Unless the eye-estimation-based classification is completed, principal component analysis (PCA) method provided simple, provisional solution for grouping trees from 135-year-old stand into three over-mentioned groups. Discriminant analysis gives more precise results compared with PCA. In the analysed stand, the most important traits for the evaluation of biosocial position were diameter at breast height, crown projection area and height.


2005 ◽  
Vol 19 (4) ◽  
pp. 935-943 ◽  
Author(s):  
Everardo V.S.B. Sampaio ◽  
Grécia C. Silva

Allometric equations to estimate total aboveground alive biomass (B) or crown projection area (C) of ten caatinga species based on plant height (H) and/or stem diameter at ground level (DGL) or at breast height (DBH) were developed. Thirty plants of each species, covering the common range of stem diameters (3 to 50 cm), were measured (C, H, DGL, DBH), cut at the base, separated into parts, weighted and subsampled to determine dry biomass. Wood density (p) of the stem and the largest branches was determined. B, C, H and p ranged from 1 to 500 kg, 0.2 to 112 m², 1.3 to 11.8 m, and 0.45 to 1.03 g cm-3. Biomass of all 10 species, separately or together (excluding one cactus species), could be estimated with high coefficients of determination (R²) using the power equation (B = aDGLb) and DGL, DBH, H or combinations of diameter, height and density. Improvement by multiplying H and/or p to DGL or DBH was small. The mixed-species equation based only on DBH (valid up to 30 cm) had a = 0.173 and b = 2.295, similar to averages of these parameters found in the literature but slightly lower than most of those for humid tropical vegetation. Crown area was significantly related to diameter, height and biomass.


2021 ◽  
Vol 7 (4) ◽  
pp. 40150-40159
Author(s):  
Luilla Lemes Alves ◽  
Eliseu Mendes Monteiro ◽  
Júnia Laura Pêgo Ribeiro ◽  
Nívea Fransuelli da Silva Madureira ◽  
Tamires Mousslech Andrade Penido ◽  
...  

Knowledge of the Crown Projection Area (CPA) allows to make inferences about the shading and to know space occupied by a tree. However, crown measurements are more time-consuming and laborious when compared to those of Circumference Breast Height (CBH). Thus, this work aimed to evaluate regression models and present the most suitable to CPA estimate of Licania tomentosa, in an urban area of São João Evangelista municipality, Brazil. Fifty trees distributed over 7 public roads were sampled. CBH and Crown Diameter (CD, m) were measured for later calculation of its projection area (CPA, m2). Four regression models were tested in order to estimate CPA as a function of CBH alone. The equation derived from of the model “” showed a homoscedastic distribution of the percentage residues, with closer deviations around the abscissa axis. It is concluded that the equation obtained with the adjustment of the simple linear model was the most efficient to estimate of the crown projection area of L. tomentosa. This projection area increased as the stem of the trees thickened.


Author(s):  
А. M. Galasheva ◽  
Е. N. Sedov

For the first time in the world and in Russia, Academician of the Russian Academy of Sciences, breeder Evgeny Nikolaevich Sedov created a series of triploid apple cultivars from intervalent crosses 2х × 4х. Triploid apple cultivars bear fruit more regularly, have higher self-fruitfulness and have fruits of high marketability. The article presents data on the study of triploid apple cultivars of the summer ripening period of the VNIISPK breeding - Augusta, Daryona, Maslovskoye, Osipovskoye, Zhilinskoye, Spasskoye and Yablochny Spas as well as the control Canadian cultivar Melba on a semi-dwarf clone rootstock 54-118. Maslovskoye, Zhilinskoye, Spasskoye and Yablochny Spas have immunity to scab. The orchard was planted in 2014, the garden planting scheme was 5 x 2 m. The indicators of the growth force (tree height, crown width and stem diameter) and the yield of trees were studied. At the age of six, the trees of triploid cultivars reached a height of 2.2 m (Maslovskoye) to 3.0 m (Yablochny Spas) on a semi-dwarf rootstock 54-118. The highest indicators of crown volume (3.3-5.3 m3), crown projection area (4.2-5.3 m2) and the cross-sectional area of the stem (46.5-52.8 cm2) were in Osipovskoye, Yablochny Spas, Zhilinskoye and Spasskoye. The highest yield in an average of three years was given by triploid scab-immune apple cultivars on a semi-dwarf rootstock 54-118: Maslovskoye, Zhilinskoye, Spasskoye and Yablochny Spas.


2004 ◽  
Vol 34 (11) ◽  
pp. 2217-2229 ◽  
Author(s):  
Douglas B Mainwaring ◽  
Douglas A Maguire

Basal area and height growth were analyzed for individual trees in uneven-aged ponderosa pine (Pinus ponderosa Dougl. ex Laws.) and lodgepole pine (Pinus contorta Dougl. ex. Loud.) stands in central Oregon. Basal area growth was modeled as a function of other stand and tree variables to address three general objectives: (1) to compare the predictive ability of distance-dependent versus distance-independent stand density variables; (2) to determine the degree to which small trees negatively affect the growth of overstory trees; and (3) to test for differences in growth efficiency between species and between indices of spatial occupancy used to define efficiency (area potentially available, crown projection area, and a surrogate for total tree leaf area). Distance-dependent variables were found to improve growth predictions when added to models with only distance-independent variables, and small trees were found to have a quantifiably negative effect on the growth of larger trees. While volume growth efficiency declined with increasing levels of spatial occupancy for lodgepole pine, ponderosa pine volume growth efficiency was greatest at the highest levels of crown base sapwood area and crown projection area. The behavior in ponderosa pine resulted from the previously recognized correlation between tree height and total leaf area or crown size. The final statistical models distinguished between the positive effect of relative height and the negative effect of increasing tree size.


Author(s):  
Andreas Rais ◽  
Martin Jacobs ◽  
Jan-Willem G. van de Kuilen ◽  
Hans Pretzsch

The current tendency towards the silvicultural promotion of mixed tree species has increased the variability in the crown structure within stands. This study shows how neighbouring trees can influence both the external crown features and internal wood properties of trees. Using terrestrial laser scanning, the crown features of 100 European beech trees, <i>Fagus sylvatica</i> L., from pure beech stands and mixed stands of beech with Douglas fir, Norway spruce, sessile oak and Scots pine were recorded. After felling and sawing, the dynamic modulus of elasticity was determined on 1623 boards from the two lower 4.1-m logs. Significant differences were found between beech trees from pure stands and those from beech–pine mixed stands in terms of crown volume (415 m<sup>3</sup> vs 766 m<sup>3</sup>), crown ratio (50.0% vs 71.5%), crown projection ratio (0.182 m cm<sup>−1</sup> vs 0.253 m cm<sup>−1</sup>) and branch angle (30.7° vs 54.1°). Multiple regression mixed models revealed significant relationships between timber stiffness and crown volume (-1.7 N mm<sup>−2</sup> m<sup>−3</sup>), crown ratio (-28.4 N mm<sup>−2</sup> %<sup>−1</sup>) and crown projection area (-9835 N mm<sup>−2</sup> m<sup>−1</sup> cm). Thus, the crown morphology of broad-leaved species reflects the tree’s long-term competitive status and suggests indicators for the assessment of mechanical–physical wood properties.


Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1198
Author(s):  
Richardson Barbosa Gomes da Silva ◽  
Mônica Moreno Gabira ◽  
Débora Zanoni do Prado ◽  
Gláucia Uesugi ◽  
Danilo Simões ◽  
...  

Research Highlights: The mean leaf angle and crown projection area can be used as criteria for grouping tree seedling species in different irrigation zones in tree nurseries with overhead microsprinkler systems, preventing water and fertilizer waste, and increasing growth. Background and Objectives: There are important gaps in current functional knowledge about how plant architecture, especially the mean leaf angles of tree seedlings, affect water and nutrient solution capture in overhead microsprinkler systems. These gaps contribute to water and fertilizer waste in tree nurseries. This research aimed to ascertain how mean leaf angles affect irrigation water capture, leaching, and the growth of tree seedlings given different volumes of irrigation. Materials and Methods: Nine species of tree seedlings with different mean leaf angles were submitted to four irrigation volumes (8, 10, 12, and 14 mm) applied daily by overhead microsprinklers in a split-plot design completely randomized. The variables leaching fraction, height, stem diameter, shoot, root, and total dry mass, Dickson quality index, crown projection area, root system quality, and leachate electrical conductivity were evaluated. Results: For species with mean leaf angles of −54, 31, 38, 42, 55, 57, and 58°, the 8 mm irrigation volume was sufficient to produce greater growth and less leaching. For species with angles of −56 and −14°, the 14 mm irrigation volume was required to produce greater growth. Conclusions: The tree seedling species with positive mean leaf angles facilitate irrigation water and nutrient solution capture, allowing the application of lower irrigation volume. On the other hand, some tree seedling species with negative mean leaf angles hinder irrigation water and nutrient solution capture, requiring the application of higher irrigation volume. When the tree seedling species have a negative mean leaf angle, but the crown projection area is small, the difficulty of water and nutrient solution reaches directly the substrate is attenuated.


1998 ◽  
Vol 28 (9) ◽  
pp. 1344-1351 ◽  
Author(s):  
Hubert Sterba ◽  
Ralph L Amateis

Crown efficiency was first defined by Assmann (1961. Waldertragskunde. BLV, München) as individual tree volume increment per unit of crown projection area. He hypothesized that within a given crown class, smaller crowns are more efficient because their ratio between crown surface and horizontal crown projection is higher. Data from a loblolly pine (Pinus taeda L.) spacing experiment were used to test if this hypothesis also holds in young loblolly pine stands and, if so, to determine if it explains the increment differences between spacings in the spacing experiment. Using individual tree height relative to plot dominant height to describe crown class, within-plot regression showed that crown efficiency decreased with crown size for trees below dominant height. This relationship was much less pronounced than indicated from Assmann's examples, although the crown surface to crown projection ratio behaved in the same way as Assmann had hypothesized. Crown efficiency as well as the crown surface to crown projection area ratio decreased with increasing density. Basal area increment per hectare increased until total crown closure approached 130% and then stayed constant. This major impact of total crown coverage brings into question the usefullness of crown efficiency as an indicator for unit area growth.


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