Temat: bark thickness - Prolib Integro

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Tytuł:: Statistical characteristics of double bark thickness at breast height based on pine (Pinus sylvestris L.), larch (Larix decidua Mill.) and oak (Quercus robur L.)
Statystyczna charakterystyka podwójnej grubości kory drzew na pierśnicy na przykładzie sosny (Pinus sylvestris L.) modrzewia (Larix decidua Mill.) i dębu (Quercus robur L.)
Autorzy:: Kazmierczak, K.
Pazdrowski, W.
Szymanski, M.
Nawrot, M.
Tematy:: statistical characteristics
tree bark
bark thickness
breast height
Scotch pine
pine
Pinus sylvestris
larch
Larix decidua
oak
Quercus robur; Pokaż więcej
Wydawca:: Uniwersytet Przyrodniczy w Lublinie. Katedra Zastosowań Matematyki i Informatyki
Powiązania:: https://bibliotekanauki.pl/articles/9695.pdf Link otwiera się w nowym oknie
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Modelowanie cech drzew i drzewostanów z wykorzystaniem modeli efektów mieszanych
Modeling of the tree and stand parameters using mixed-effects models
Autorzy:: Bronisz, K.
Tematy:: lesnictwo
drzewostany
drzewa lesne
grubosc kory
cechy dendrometryczne
modelowanie
modele liniowe
modele efektow mieszanych
bark thickness
scots pine
regression
linear mixed−effects models; Pokaż więcej
Wydawca:: Polskie Towarzystwo Leśne
Powiązania:: https://bibliotekanauki.pl/articles/980258.pdf Link otwiera się w nowym oknie
Opis:: Regression analysis is one of the most popular statistical modeling tools, which can define linear or nonlinear relationships between individual trees and stands parameters. Mixed−effects models are one of the contemporary trends of those regression methods. These models can be applied to describe such features as: height, biomass, taper, site index or volume both at the level of a single tree and whole forest ecosystems. The aim of this work is to present the characteristics of the mixed−effects model, the applicability of linear and nonlinear mixed−effects models in forest studies, and the example of a linear mixed−effects model defining the relationship between bark thickness and diameter at breast height for Scots pine (Pinus sylvestris L.) in comparison to the linear fixed−effect model. Goodness−of−fit for the obtained linear mixed−effect model indicate its better fit to the pine bark thickness than in the case of the mixed−effects model. Moreover, most of the published research results indicate the predominance of both linear and nonlinear mixed−effects models according to fixed−effect ones. These studies indicate the wide possibilities of using mixed−effect models in forestry. However, there are also results pointing to the disadvantages of these models and put into question the legitimacy of their use in forest research. This fact to some extent confirms the results (residuals behavior) obtained in this study. Therefore, it seems necessary to conduct further research, which on the one hand will allow the potential of this solution to be used, and on the other hand will help to clarify emerging doubts.
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Dokładność sposobów określania miąższości dłużyc bez kory według normy PN-D-95000:2002 na przykładzie sosny zwyczajnej (Pinus sylvestris L.) z terenu Nadleśnictwa Płaska
Accuracy of methods to determine under bark volume of logs according to the PN-D-95000:2002 standard – a case study of Scots pine (Pinus sylvestris L.) from the Płaska Forest District
Autorzy:: Polkowski, K.
Zarzyński, P.
Tomusiak, R.
Tematy:: lesnictwo
sosna zwyczajna
Pinus sylvestris
drewno sosnowe
dluzyce
miazszosc drewna
miazszosc dluzyc bez kory
pomiary
metody obliczen
polskie normy
norma PN-D-95000:2002
bark thickness
bark reduction
volume of large−sized wood
under−bark volume; Pokaż więcej
Wydawca:: Polskie Towarzystwo Leśne
Powiązania:: https://bibliotekanauki.pl/articles/985738.pdf Link otwiera się w nowym oknie
Opis:: The State Forests, National Forest Holding operates on the principle of financial independence, and the sale of wood is the primary source of income of the institution. Raw wood is sold with the bark, although the registry applies to the wood without bark. It was hypothesized that the method of bark volume reduction may have a significant impact on the registered volume. The material collected in the Płaska Forest District was used to assess the impact of method of bark volume reduction presented in the PN−D−95000:2002 standard on the volume of Scots pine logs in thinned and harvest stands growing on fresh coniferous forest habitat. Analysis of the accuracy and precision of each method were carried out on the basis of sectional measurements of 180 logs (90 per stand type). Four methods were compared: table deduction depending on the diameter of the stem (method 1), measurement of bark thickness with manual bark gauge (method 2a), mechanical removal of the bark using a spokeshave at the place of measurement (method 2b), and calculation of the log volume with Huber formula and subsequent subtraction of the bark volume determined based on special ratio (method 3). All methods caused negative systematic error, and thus have a constant tendency to underestimate the volume of Scots pine logs. At the same time, the underestimated log volume varies depending on the method used. To the greatest extent it is lowered using method 1, as it differs significantly from the other methods. Slightly smaller errors are characterized by the method 2a, for which the average error rate also differs from the other methods. The smallest errors are provided by methods 2b and 3, between which we found no significant differences. Analyses indicate that the preferred method of determining the volume inside bark is a mechanical removing of bark, measuring the diameter without bark and calculation of the volume with Huber formula. It is also noteworthy to take into account the deduction percentage of bark in the logs of large−sized wood.
Dostawca treści:: Biblioteka Nauki

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