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Wyświetlanie 1-4 z 4
Tytuł:
Zastosowanie metod biofizycznych do oceny zywotnosci sadzonek sosny, swierka i modrzewia
Autorzy:
Wesoly, W.
Pukacki, P.M.
Naparty, E.
Powiązania:
https://bibliotekanauki.pl/articles/820003.pdf
Data publikacji:
1998
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
Pinus
Picea
metody biofizyczne
lesnictwo
Larix
pomiary
szkolkarstwo lesne
swierk
sosna
modrzew
sadzonki
zywotnosc
drzewa lesne
Źródło:
Sylwan; 1998, 142, 08; 55-64
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problematyka pomiarów oraz określania miąższości martwego drewna na kołowych powierzchniach próbnych
Measurement and calculation of the volume of deadwood on circular sampling plots
Autorzy:
Bujoczek, L.
Powiązania:
https://bibliotekanauki.pl/articles/989747.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
powierzchnie probne kolowe
drewno martwe
miazszosc drewna
pomiary drewna
metody pomiarow
coarse woody debris
snags
shape
decomposition
field methods
volume determination
Opis:
The paper analyzes two methods of deadwood (DW) measurements on circular sampling plots. In the first method, the volume of DW is measured within the circumference of the sampling plot irrespective of the fact whether the live tree was located inside or outside the plot. The other method requires the measurement of only that DW, which can be attributed to trees that originally grew within the sampling plot. This requires identification all debris fragments originating from those trees both within and outside the sampling plot. Additionally, the paper compares the results obtained using Smalin's and Huber's formulas and discusses the influence of decomposition stage on the calculated volume of lying deadwood. Measurements were conducted in two stands. In each of them 20 circular sampling plots (4 or 5 ares) were established. In both stands, the second investigated measurement method led to a lower mean DW volume (by 6.3% and 27.2%). In practice, it was very difficult to identify DW from the outside of the sampling plots as high trees growing close to the plot had their fragments lying up to several dozen meters away. If a tree was very fragmented upon falling, it was difficult to find all the relevant pieces of DW and determine whether they derived from the sampling plot or not. The volume of lying DW calculated according to Smalin's formula was by 5% higher. In case of 7.7% of the 194 inventoried fragments of lying DW the transverse cross−section changed from circular to misshapen. The application of formulas accounting for decomposition decreased the calculated volume of lying DW by 5.1%. Taking into consideration the time−effectiveness and accuracy of measurements, it has been found that for most stands the best method is to measure the ends of DW pieces, calculating the length of segments from polar coordinates (using the measurement principles presented in the figures). In addition, especially in measuring large trees, one should take into account changes in shape attributable to decomposition, which may influence the calculation of DW volume. It is recommended that all DW fragments within a circular sampling plot should be measured irrespective of whether the tree from which they derive grew inside or outside the plot.
Źródło:
Sylwan; 2015, 159, 10; 795-803
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Określenie składu gatunkowego lasów Góry Chojnik (Karkonoski Park Narodowy) z wykorzystaniem lotniczych danych hiperspektralnych APEX
Identification of tree species in Mt Chojnik (Karkonoski National Park) forest using airborne hyperspectal APEX data
Autorzy:
Raczko, E.
Zagajewski, B.
Ochtyra, A.
Jarocińska, A.
Marcinkowska-Ochtyra, A.
Dobrowolski, M.
Powiązania:
https://bibliotekanauki.pl/articles/989774.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Karkonoski Park Narodowy
gory
Chojnik
lasy
sklad gatunkowy
metody badan
teledetekcja
pomiary hiperspektralne
skaner APEX
svm classification
apex hyperspectral data
species structure
Opis:
We used hyperspectral data from APEX scanner (288 spectral bands in 380−2500 nm spectral range; 3,5 m spatial resolution) to classify five tree species occurring in the area of Mt. Chojnik in the Karkonoski National Park (south−western Poland). Data used to delimit learning and verification polygons were acquired during field research in August 2013, when ground truth polygons were acquired using device equipped with GPS receiver. Raw APEX data went through radiometric and geometric correction at VITO office. To reduce processing time, 40 most informative bands were selected using information content analysis. The Support Vector Machines (SVM) algorithm was used for classification of the following tree species: Fagus sylvatica L., Betula pendula Roth, Pinus sylvestris L., Picea alba L. Karst and Larix decidua Mill. Final classification had 78.66% overall accuracy with Kappa coefficient equal to 0.71. The best classified species included beech (87.09%) and pine (83.96%), while the worst results were obtained for larch (60.29%). Low accuracy for larch could be caused by the fact that most of larch trees in the research area grow in small patches, which made it hard to specify large enough sample of training data. All classified tree species had producer's accuracy of at least 60%, with the highest value reaching 87%. User's accuracies were from 53% for pine to 85% for beech. It is possible to classify tree species using hyperspectral data with moderate to high accuracy even if the data used lacked atmospheric correction. Further work will focus on improving the classification accuracy and use of neural networks based classification methods. Results from this paper will serve as basis for tree species map of the Karkonoski National Park.
Źródło:
Sylwan; 2015, 159, 07; 593-599
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
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.
Powiązania:
https://bibliotekanauki.pl/articles/985738.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Leśne
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
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.
Źródło:
Sylwan; 2019, 163, 06; 460-468
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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