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Tytuł:
Impacts of forest spatial structure on variation of the multipath phenomenon of navigation satellite signals
Autorzy:
Brach, Michał
Stereńczak, Krzysztof
Bolibok, Leszek
Kwaśny, Łukasz
Krok, Grzegorz
Laszkowski, Michał
Powiązania:
https://bibliotekanauki.pl/articles/2044153.pdf
Data publikacji:
2019
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
GNSS
multipath
random forest
Borut
forest structure
LiDAR
Opis:
The GNSS (Global Navigation Satellite System) receivers are commonly used in forest management in order to determine objects coordinates, area or length assessment and many other tasks which need accurate positioning. Unfortunately, the forest structure strongly limits access to satellite signals, which makes the positioning accuracy much weak comparing to the open areas. The main reason for this issue is the multipath phenomenon of satellite signal. It causes radio waves reflections from surrounding obstacles so the signal do not reach directly to the GNSS receiver’s antenna. Around 50% of error in GNSS positioning in the forest is because of multipath effect. In this research study, an attempt was made to quantify the forest stand features that may influence the multipath variability. The ground truth data was collected in six Forest Districts located in different part of Poland. The total amount of data was processed for over 2,700 study inventory plots with performed GNSS measurements. On every plot over 25 forest metrics were calculated and over 25 minutes of raw GNSS observations (1500 epochs) were captured. The main goal of this study was to find the way of multipath quantification and search the relationship between multipath variability and forest structure. It was reported that forest stand merchantable volume is the most important factor which influence the multipath phenomenon. Even though the similar geodetic class GNSS receivers were used it was observed significant difference of multipath values in similar conditions.
Źródło:
Folia Forestalia Polonica. Series A . Forestry; 2019, 61, 1; 3-21
0071-6677
Pojawia się w:
Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
State and structure of urban forests in Kharkiv region
Autorzy:
Musienko, Sergiy
Lyalin, Oleksandr
Tkach, Ludmila
Bondarenko, Vira
Kolenkina, Marina
Kolchanova, Olena
Powiązania:
https://bibliotekanauki.pl/articles/2041681.pdf
Data publikacji:
2020
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
urban forest structure
urban areas
state enterprises
environmental condition
Opis:
Deterioration of water conservation, water protection, water-regulating, soil-protective, health and recreational properties of urban forests is an urgent problem in urban areas. Researching the state and growth characteristics of urban forests will help in developing the best forestry management activities of care. The objects of study were the urban forests of Kharkiv region. During the study, methods commonly used in forestry, forest inventory and biometrics were applied. The investigation determined a species range of urban forests and prevailing species in terms of users. The stands’ distribution by species composition, age groups, their average age, site class, stand density and timber volume was determined. The practicability of further research of these objects was proved.
Źródło:
Folia Forestalia Polonica. Series A . Forestry; 2020, 62, 1; 46-52
0071-6677
Pojawia się w:
Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Struktura lasów okolic Warszawy na podstawie zdjęć satelitarnych i lotniczych
Analyzing structure of forests near Warsaw on the basis of satellite imagery and aerial photographs
Autorzy:
Wrzesień, M.
Powiązania:
https://bibliotekanauki.pl/articles/130850.pdf
Data publikacji:
2003
Wydawca:
Stowarzyszenie Geodetów Polskich
Tematy:
struktura lasu
klasyfikacja
wskaźniki ekologiczne
forest structure
classification
ecological indices
Opis:
Celem pracy było zweryfikowanie klasyfikacji nadzorowanej jako metody badania struktury gatunkowej i wiekowej drzewostanów w Rezerwacie Sieraków, Uroczysku Chojnów i Lesie Kabackim oraz ocena wykorzystanych materiałów. Ponadto zbadanie struktury kompleksów leśnych za pomocą wskaźników z ekologii krajobrazu. Do klasyfikacji, która była podstawową wykorzystywaną metodą, wzięto pod uwagę dwa trzykanałowe zestawy (TM2, TM3, TM4 oraz TM3, TM4, TM5) oraz pojedynczy kanał TM4. Określono klasy możliwe do wydzielenia na obrazach satelitarnych i na zdjęciach lotniczych. Dokonano wyboru pól treningowych i określono sygnatury spektralne poszczególnych gatunków i klas wieku. Wykonano klasyfikację nadzorowaną, korzystając z reguły największego prawdopodobieństwa. Uzyskano mapy, których dokładność określono, posługując się macierzą błędów i współczynnikiem zgodności kappa. Wybrano mapy sklasyfikowane z największą dokładnością i poddano je analizie z użyciem wskaźników z ekologii krajobrazu. Po przeanalizowaniu wyników sformułowano następujące wnioski: klasyfikacja nadzorowana obrazów Landsat umożliwia określenie składu gatunkowego i przedziałów klas wieku heterogenicznych kompleksach leśnych w sposób ogólny, skład gatunkowy jest możliwy do wydzielenia z większą dokładnością niż przedziały klas wieku, mimo położenia kompleksów leśnych w jednym regionie biogeograficznym nie można stworzyć jednolitych sygnatur spektralnych, błędy wynikają z uśrednionej informacji zawartej w pikselu, uogólnionych danych zapisanych na mapach drzewostanowych i opisach taksacyjnych, rozbieżności terminów wykonania zobrazowania i map, cyfrową analizę zdjęć lotniczych uniemożliwia zbyt szczegółowy obraz oraz jakość materiałów, które charakteryzują się znaczną zmiennością tonalną w zależności od położenia względem środka zdjęcia, wskaźniki opisujące strukturę drzewostanów ilościowo uzupełniają informację jakościową zawartą na mapach poklasyfikacyjnych, wyniki analizy ilościowej są uzależnione od rodzaju danych teledetekcyjnych.
Forests are rich ecosystems, which fulfill significant functions as scientific, educational and finally recreational. Forest landscapes play a key role, particularly near urban areas like Warsaw, where they are affected by the town and its inhabitants. Collecting data about forests and analyzing it are desirable tasks for the purposes of environmental monitoring, protection, planning and management in different scales (spatial/time). Remotely sensed data proved to be very useful sources of information about forest characteristics as a specific ecosystem and as a part of the boarder landscape. The aim of this study is to present methods and techniques used for analyzing and effectively using satellite images and aerial photographs for certain purposes in forestry and environment protection. Analyses were made on the example of Landsat ETM+ satellite images acquired in 2000 and set of aerial photographs obtained in 1997 (PHARE, true color, 1:26000, 1:5000) and 1992 (color infrared, 1:10000). The areas under study are three forest complexes located near Warsaw: Kampinoski National Park, Chojnowski Landscape Park and Las Kabacki Reserve, which differ in size, diversity, and level of protection. Automated solutions in forest studies deliver objective and high quality thematic data, which are competitive to the conventional survey mapping methods.
Źródło:
Archiwum Fotogrametrii, Kartografii i Teledetekcji; 2003, 13b; 497-505
2083-2214
2391-9477
Pojawia się w:
Archiwum Fotogrametrii, Kartografii i Teledetekcji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza zależności struktury lasu od wieku na przykładzie drzewostanów sosnowych
Analysis of forest structure in relation to age – Scots pine case study
Autorzy:
Sławski, M.
Powiązania:
https://bibliotekanauki.pl/articles/973837.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
drzewostany sosnowe
starodrzew
struktura drzewostanu
wiek drzewostanu
zmiany struktury drzewostanu
leśnictwo
forest structure
old−growth
pine forest
Opis:
Structure of pine forests develops with age and becomes more complex in older stands. Key attributes of old−growth forest structure include presence of huge trees, coarse woody debris, hollow trees, trees with fungi, clearings, two or more layered structure. In total, 26 attributes show positive correlation with age. This set can be used as base for old−growthness index. Cluster analysis divided forest stands into four groups with different level of maturity. Stands older than 160 years occurred fully developed. It seams that in sustainable forestry attributes of old−growth forests can be maintained as key elements for biodiversity.
Źródło:
Sylwan; 2011, 155, 01; 10-20
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of mangrove forest structures on wave attenuation in coastal Vietnam
Autorzy:
Bao, T.Q.
Powiązania:
https://bibliotekanauki.pl/articles/48094.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
brackish water
coastal region
forest structure
mangrove forest
marine environment
river mouth
saline water
storm
terrestrial environment
Vietnam
water quality
wave
wave attenuation
Opis:
This paper analyses wave attenuation in coastal mangrove forests in Vietnam. Data from 32 mangrove plots of six species located in 2 coastal regions are used for this study. In each plot, mangrove forest structures and wave height at different cross-shore distances are measured. Wave height closely relates to cross- shore distances. 92 exponential regression equations are highly significant with R2 >0.95 and P val. <0.001. Wave height reduction depends on initial wave height, cross-shore distances, and mangrove forest structures. This relationship is used to define minimum mangrove band width for coastal protection from waves in Vietnam.
Źródło:
Oceanologia; 2011, 53, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bivariate distribution characteristics of spatial structure in five different Pinus massoniana forests
Autorzy:
Zhang, Ren-bo
Ding, Gui-jie
Luo, Xiao-man
Chen, Mo-fang
Powiązania:
https://bibliotekanauki.pl/articles/956829.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
uniform angle index
mingling
dominance
structure-based forest management
Opis:
Bivariate distribution is an effective approach to spatial structure analysis. Combined with two of the three structure parameters (uniform angle index (W), dominance (U) and mingling (M)), the structural bivariate characteristics of five different Pinus massoniana forests were explored in this study. Our objective was to provide a theoretical direction for structure-based and detailed management in P. massoniana forests. The bivariate traits showed that mixed artificial or secondary forests predominated by P. massoniana trees do not typically achieve the highest mingling level. Trees under extreme mingling conditions were rare and typically comprised of non-dominant species instead of dominant ones in P. massoniana forests; these trees were generally overtopped and randomly distributed. Management implications can be extracted comparing the bivariate traits between all species and dominant species. The original community structure, development stage, and mixed-tree species number affect the univariate M and, furthermore, the two bivariate U-M and W-M distributions in mixed forests. Forest type has little effect on all-species W-U traits compared to those of the dominant species. U-M traits should be adjusted first if the random frequency values are highest in W-U and W-M bivariate distribution, and it is necessary to determine whether these two bivariate traits shade the W univariate. Adjustments made based on bivariate distribution can reveal poor frequency combinations for foresters to target; this allows the simultaneous adjustment of dual aspects of forest structure based on one bivariate index. Our results show that bivariate distribution may provide very useful information for the management of P. massoniana and other forests.
Źródło:
Dendrobiology; 2017, 78; 75-84
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Struktura lasów w Polsce na podstawie danych wielkoobszarowej inwentaryzacji stanu lasu
Structure of forests in Poland based on National Forest Inventory data
Autorzy:
Jabłoński, M.
Wysocka-Fijorek, E.
Budniak, P.
Powiązania:
https://bibliotekanauki.pl/articles/987174.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
lesnictwo
Polska
lasy
struktura lasu
inwentaryzacja lasu
inwentaryzacja wielkopowierzchniowa
powierzchnie probne WISL
drzewostany
cechy taksacyjne
gatunki panujace
struktura pionowa
struktura wiekowa
forest structure indicators
forest description
nfi
Opis:
In most of European countries, basic information about forests that is used for its monitoring and formulation of national policies comes from the National Forest Inventories (NFIs). Assessment of forest resources at the national level was initiated in Poland in 2005. In 2014, the second cycle of NFI was completed. Since 2010, results of NFI are the main source of information about the amount of forest resources in Poland, their structure and condition. In the paper, we analyse the indicators of forest structure. Classification of forest categories (forested, temporary non−forested, related to forestry), vertical stand structure, species composition and age structure determined directly from NFI's sample plots were compared with descriptions of stands in which plots are located. Data from more than 29,000 NFI sample plots measured in 2010−2014 were analysed. Our results demonstrate that the share of temporary non−forested areas (resulting from manage− ment practices) assessed from NFI plots is higher than this based upon the stands description (3.9% and 1.8% respectively). We also observed that results of NFI show the huge discrepancy in percentage of land related to forestry (forest roads generally) in forests of private property comparing to cadastral data (1,2% and 0,04% respectively). Most of forests in Poland (92% based on NFI) are single−layer stands. But it should be emphasised that NFI indicate more than twice higher share of two−layer stands (4.8%) than that resulting from description of stands in which samples are located (2.2%). However, only one third of NFI plots located in two−generation and uneven−aged stands was assessed in the same way. On 80% of sample plots dominant species was in accordance with stand description. On 85% plots there were compatibility of the age of dominant species with age recorded in forest management plans. The results of our research confirm that description of the entire diversity of forests by any of the indicators is not practically possible. Simplifying the forests description occurs during NFI measurements as well as within forest management planning. However, some issues need clarification and additional analysis when NFI is used as a source of forest structure. NFI plots with maximal size of a few hundred square meters seem to be too small to observe vertical structure of stands. On the other hand, it should be recog− nized whether division of the sample plots into smaller sections does not cause overestimation of the area of temporary non−forested land.
Źródło:
Sylwan; 2017, 161, 04; 267-276
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ struktury lasu na liczebność i wielkość terytorium lelka
Effect of the forest structure on the number and territory size of nightjar Caprimulgus europaeus
Autorzy:
Stasiak, K.
Grzywaczewski, G.
Gustaw, W.
Cios, S.
Powiązania:
https://bibliotekanauki.pl/articles/991563.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
Nadlesnictwo Pulawy
struktura drzewostanu
lasy
ptaki
lelek
Caprimulgus europaeus
liczebnosc
terytoria legowe
wielkosc terytorium
zageszczenie populacji
preferencje siedliskowe
caprimulgus europaeus
territory size
density
forest structure
Opis:
We analysed 7 territories of the nightjar located in the Puławy Forest District (eastern Poland). Density of the breeding population on the studied area was 0.88 territory/km². The smallest territory covered 4.5 ha, while the biggest one – 18.7 ha (average 13 ha). Birds were found in a loose birch and pine forest, in the plantation and nearby the working railway. Significant differences in open area contribution and in share of undergrowth and brushwood were found between analysed territories and random patches. Greater biodiversity was found in places chosen by birds.
Źródło:
Sylwan; 2013, 157, 04; 306-312
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficiency of different forest types in carbon storage depends on their internal structure
Autorzy:
Gheorghe, I.F.
Biris, I.A.
Valcu, C.-M.
Powiązania:
https://bibliotekanauki.pl/articles/57973.pdf
Data publikacji:
2010
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
forest vegetation
efficiency
forest type
carbon storage
internal structure
temperate forest
productivity
Opis:
Forest vegetation is a key factor in the maintenance of global carbon cycle balance under the present climate change conditions. Forest ecosystems are both buffers against extreme climatic events accompanying climate change and carbon sinks diminishing the environmental impact of anthropogenic greenhouse gas emissions. We investigated the influence of stand structure and site characteristics on the productivity and carbon storage capacity of temperate forest types. Predictors of species productivity were parameters such as stand density, age, height, average diameter and wood density. Morus alba (L.) was more productive than average both in terms of annual volume increment and annual biomass gain, while Quercus sessiliflora (Matt.) Lieb. and Quercus frainetto (Ten.) were significantly less productive than average. Differences in stand productivity were explained by stand density, age, height, altitude, type of regeneration and species composition. Statistically significant differences were measured between the productivity of stands dominated by different woody species, with low productive stands dominated by slow growing species with high wood density like Quercus or Fagus, and highly productive stands rich in fast growing species with low wood density like Populus or Salix. Stands with different plant communities in the underlying herbaceous layer also tended to have different levels of productivity.
Źródło:
Acta Societatis Botanicorum Poloniae; 2010, 79, 4
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial structure of managed beech-dominated forest: applicability of nearest neighbors indices
Autorzy:
Szmyt, J.
Powiązania:
https://bibliotekanauki.pl/articles/41043.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
spatial structure
beech forest
forest
applicability
nearest-neighbor index
Fagus sylvatica
forest management
Opis:
High structural diversity is often attributed to old-growth forests, usually established naturally and unmanaged. Forest diversity should be considered not only in terms of species diversity and richness but also the variation in trees dimension and their spatial distribution have to be taken into consideration. The main goal of this paper was the answer if nearest neighbor indices are suitable for spatial forest structure description. To answer this question results obtained from 3 managed beech-dominated forests from natural regeneration are presented and discussed. The following indices were calculated: Clark-Evans aggregation index (R), DBH and height differentiation indices (TD and TH, respectively) and mingling index (DM) analyzing horizontal and vertical spatial structure of the forest. Results indicated that managed beech forests demonstrated rather homogenous spatial structure in both aspects. Living trees as well as future crop trees were mostly regularly distributed. Spatial variation in DBH and height between living nearest neighbors was rather low. The lowest variation in sizes was demonstrated by future crop trees. Mature beech forests revealed single species structure and other tree species – if present – were spatially segregated from beech. It can be supposed that high homogeneity structure of these forests results from biological characteristics of this species as well as thinning treatments conducted by foresters.
Źródło:
Dendrobiology; 2012, 68
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Opracowanie technologii przetwarzania archiwalnych materiałów fotogrametrycznych do badań zmienności krajobrazu na przykładzie Słowińskiego Parku Narodowego
Technology of processing archival aerial phothos for changes analysis of Słowinski National Park Landscape
Autorzy:
Michałowska, K.
Głowienka, E.
Mikrut, S.
Powiązania:
https://bibliotekanauki.pl/articles/129978.pdf
Data publikacji:
2007
Wydawca:
Stowarzyszenie Geodetów Polskich
Tematy:
photogrammetry
structure
forest stand
nature reserve
yew
Opis:
W artykule przedstawiono technologie wykonania aerotriangulacji na bazie archiwalnych zdjęć lotniczych z lat 1951, 1964, 1975 i 1984, wykonanych w różnych skalach dla terenu Słowińskiego Parku Narodowego. Zdjęcia, w postaci diapozytywów, pozyskano z zasobów Zarządu Geografii Wojskowej w Warszawie. Jakość zdjęć w poszczególnych rocznikach była bardzo zróżnicowana. W celu podniesienia jakości opracowań fotogrametrycznych oraz możliwości fotointerpretacyjnych zastosowano metody przetwarzania obrazów cyfrowych. W pierwszym etapie przetwarzania zdjęć wykonano orientacje wewnętrzna i wzajemna zdjęć dla wszystkich bloków. Ze względu na specyfikę terenów SPN pomiar punktów wiążących był w znacznym stopniu utrudniony (ponad 60% opracowywanego bloku zdjęć zajmują ruchome wydmy, wody Bałtyku oraz jezior Łebsko, Gardno). Z uwagi na brak możliwości wyrównania bloku aerotriangulacji w systemie DEPHOS, proces ten wykonano w środowisku ImageStation. Konieczne było transformowanie danych z formatu Dephos’a (pikselowe współrzędne punktów wiążących na poszczególnych zdjęciach) do formatu ImageStation. Transformacji współrzędnych dokonano przy pomocy programu TRANSPOL. Jakość zdjęć miała bezpośredni wpływ na dokładność pomiarów zarówno punktów wiążących jak i fotopunktów, a także interpretacje szczegółów terenowych w późniejszym procesie generowania Numerycznego Modelu Terenu (NMT), który był podstawa analiz przestrzennoczasowych krajobrazu Słowińskiego Parku cechującego się wyjątkowo silna dynamika podłoża i roślinności. Prace były realizowane w ramach projektu KBN Nr N304 077 31/3060 „Modelowanie przestrzenne zmian wybranych elementów środowiska Słowińskiego Parku Narodowego”.
The paper presents technology of aerotriangulation on the basis of multitemporal (1951, 1964, 1975, and 1984), aerial photos of the Słowinski National Park in various scale Those photos, as negatives, were obtained from the resources of military geographic authorities Military Geography Management in Warsaw. The quality of photos in particular year was highly diversified. Therefore, methods of digital image processing, such as filtration, "image reinforcement", or preliminary tonal balancing were applied to improve the quality of those photogrammetric materials, and to improve the possibilities of their photointerpretation. The DEPHOS photogrammetric station was used to perform measurements, necessary for adjustment of the aerotriangulation block. In the first stage, internal and relative orientations were performed for all photo blocks. Due to the specificity of the Park area, the measurement of binding points was substantially hindered (more than 70% of the photo block being processed are occupied by migrating dunes, the Baltic Sea, and the Łebsko and the Gardno lakes). In view of the lack of the possibility to balance the aerotriangulation block under the DEPHOS system, the process was performed in ImageStation environment. It was necessary to transform data from the Dephos format (pixel coordinates of binding points on particular photos) to the ImageStation format. The quality of photos directly affected the accuracy of measurements, both in relation to binding points, and to photopoints, as well as the interpretation of terrain details in the later process of DTM generation. The said research works were conducted under the research project No. N304 077 31/3060 [financed by the State Committee for Scientific Research and] titled "Spatial Modelling of Changes in Selected Elements of the Słowinski National Park. " DTM was the basis for spatial and time analyses of the Słowinski National Park landscape, which is marked by its exceptionally strong dynamics of substrate and vegetation.
Źródło:
Archiwum Fotogrametrii, Kartografii i Teledetekcji; 2007, 17b; 495-504
2083-2214
2391-9477
Pojawia się w:
Archiwum Fotogrametrii, Kartografii i Teledetekcji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of a fresh broadleaved forest site and fresh mixed broadleaved forest site on selected parameters and ratios of silver birch (Betula pendula Roth.) wood fibre structure
Autorzy:
Lachowicz, H.
Paschalis-Jakubowicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/52429.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Drewna
Tematy:
fresh broadleaved forest
fresh mixed broadleaved forest
forest site
wood parameter
silver birch
Betula pendula
wood fibre
wood structure
Opis:
The variability of selected ratios characterising the dimensions and shape of silver birch wood fibres was determined based on the site where the trees grow. Two sampling areas were selected, located in the Biała Podlaska Forest District in eastern Poland. Samples for testing were taken from trees approx. 45–50 years old, growing on a fresh broadleaved forest site and on a fresh mixed broadleaved forest site. On these two sites, silver birch occurs most widely as a dominant species, both in terms of stand area and volume, in Poland. A statistical analysis was performed of selected parameters of the wood fibre structure such as length, width, lumen and cell wall thickness, as well as of the wood fibre structure ratios belonging to the basic properties of fibrous pulp: the felting power, flexibility ratio, coefficient of rigidity, Runkel and Mühlsteph ratios, as well as the compactness index. It was demonstrated that the site from which birch material originates has a significant impact on the average values of: fibre length, lumen, flexibility ratio, and the coefficient of rigidity, as well as the Runkel and Mühlsteph ratios. However, analyses did not prove any major impact of the site on the average values of: fibre width and wall thickness, the felting power or the compactness index of silver birch wood.
Źródło:
Drewno. Prace Naukowe. Doniesienia. Komunikaty; 2014, 57, 193
1644-3985
Pojawia się w:
Drewno. Prace Naukowe. Doniesienia. Komunikaty
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in horizontal structure of natural beech forests on an altitudinal gradient in the Sudetes
Autorzy:
Vacek, Z.
Vacek, S.
Bilek, L.
Remes, J.
Stefancik, I.
Powiązania:
https://bibliotekanauki.pl/articles/41453.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
structural change
horizontal structure
natural forest
beech forest
European beech
Fagus sylvatica
forest dynamics
altitudinal gradient
Sudetes Mountains
Opis:
The article describes horizontal structure of the tree layer, natural regeneration, snags and crown projections of natural beech stands on three permanent research plots in the wide altitudinal range in the Krkonoše Mts (Czech Republic). The spatial structure was classified from 1980 to 2010 and subsequently the prediction of spontaneous development with an outlook for 30 years (to 2040) was done by growth simulator. Hopkins-Skellam index, Pielou-Mountford index, Clark-Evans index and Ripley’s K-function were calculated. Further, the vertical structure and total diversity index was evaluated. The horizontal structure of individuals in the tree layer had not changed significantly during the monitored years. Tree spatial pattern of the lowest altitude lying herb-rich beech forest was mostly regular to random, in acidophilous mountain beech forest predominantly random and in fragments of beech groups around the timberline aggregated. Juvenile growth on all investigated plots was distributed aggregated and snags randomly. The horizontal structure of crown projection centroids had always higher values toward the regularity than tree layer and was random to regular. The result of principal component analysis also confirmed that spatial pattern was dependent on the altitude, but also on the number of trees.
Źródło:
Dendrobiology; 2015, 73
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ekonomiczne aspekty różnych sposobów odnowienia lasu
Economic aspects of different ways of renovation of forest
Autorzy:
Szramka, H.
Powiązania:
https://bibliotekanauki.pl/articles/1022740.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
odnowienia lasu
aspekty ekonomiczne
lesnictwo
forest regeneration
cost structure
Opis:
The paper deals with artificial and natural regeneration cost structure. The studies confirm the economic profitability of natural regeneration method.
Źródło:
Sylwan; 2005, 149, 11; 59-65
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in the structure of tree stands on bog habitats in the Bialowieza forest
Autorzy:
Czerepko, J.
Powiązania:
https://bibliotekanauki.pl/articles/38483.pdf
Data publikacji:
2010
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
structural change
tree stand
bog habitat
Bialowieza Forest
bog forest
permanent plot
plant succession
stand structure
Opis:
The analyses of 4 permanent study plots located in the Białowieża forest (NE Poland, at 52º43´ N, 23º50´ E) were carried out 4 times, first time in 1973 or 1974 and next in 1985, 1998, 2008. The paper presents the results of a long–term study on natural forest dynamics in two forest communities: raised-bog pine forest of the association Ledo-Sphagnetum magellanici Sukopp 1959 em. Neuhäusl 1969 and transitional bogs represented by the boreal spruce forest Sphagno girgensohnii-Piceetum Polak. 1962. On each measurement date the DBH of all trees were recognized. At the same time, stems of shrub species as well as tree species with the height lower than 1.3 m were counted within the experimental areas. During the study period the structure of stands changed significantly. The major change observed on raised bog sites was an increase in numbers of Betula spp., Picea abies (L.) H. Karst. and Quercus robur L. After 34th-year of observations the boreal spruce forest stand partly passed the terminal phase and regenerated. New species occurred in the stands, especially in their lower layer, are typical for oak-lime-hornbeam forest, such as e.g. Carpinus betulus L., Q. robur, Acer platanoides L. Rapid development of Corylus avellana L. was also observed. During last decades, the decrease in the number of Pinus sylvestris L. trees has been observed. The results of analyses of stand data in four research periods show that the wetland habitat of the Białowieża forest has been a subject to the processes of succession conditioned by environmental changes such as desiccation through lowering of the water table as well as climatic changes entailing inter alia an increase of the air temperature and a decrease of precipitation.
Źródło:
Folia Forestalia Polonica. Series A . Forestry; 2010, 52, 1
0071-6677
Pojawia się w:
Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 62

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