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Wyświetlanie 16-30 z 214
Tytuł:
A Study on the Correlation between Wood Moisture and the Damping Behaviour of the Tonewood Spruce
Autorzy:
Göken, J.
Fayed, S.
Schäfer, H.
Enzenauer, J.
Powiązania:
https://bibliotekanauki.pl/articles/1030781.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
spruce wood
musical instruments
wood moisture
damping measurement
Opis:
In acoustic musical instruments special attention needs to be paid to those particularly sensitive parts made of tonewood whose function is to respond to vibrations. One of the most important tonewoods is spruce because of its good resonance properties. Spruce is especially used for soundboards, these being the primary source of sound. Piano manufacturers dry their soundboards to approximately 6% wood moisture, at which drying stage they are glued into the instrument. Fluctuations of the moisture content in the wood affect the tone. With changing moisture content, the instrument can go out of tune, even cracks can appear at very low moisture content in the wood. In addition, the tone colour will change. This may result from changes in the hammer felt or from changes in the vibration properties of the soundboard. Strain- and frequency-dependent damping measurements were carried out on spruce wood at different wood moisture contents in order to investigate the effect of the moisture content on the vibration behaviour. Wood which is slowly dried in air for several years is preferably used for high-class pianos. Therefore, damping measurements on new and on more than 130-year old spruce wood samples were performed.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1241-1260
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The radial growth-competition relationship in Picea abies stands affected by windfall
Autorzy:
Badea, O.
Dumitru, I.
Cojocia, C.
Popa, I.
Powiązania:
https://bibliotekanauki.pl/articles/41406.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Norway spruce
stand
Picea abies
windfall
risk factor
Opis:
Actual status of mountain forests especialy, of Norway spruce (Picea abies Karst. (L)) stands is a result of combined action between forest management measures and biotic and abiotic risk factors. In this context, tree growth dynamics is a result of multifactor interaction (competition, disturbance, management practice, climate etc.). Wind damage affect the stand structure and normal ecosystem functions including the relationship between individual tree growth and competition processes. Though, it is recorded a diminishing of productive capacity for affected stands as well as a significant diameter increment for remaining standing trees. The correlation between tree growth (cumulate basal area increment in the last 10 years) and competition (Hegyi and Schutz competition indices) was analysed in stands with different windfall intensity. No relationship between tree growth and competition was observed in highly affected stands. Schutz competition index explains better individual tree growth comparing with Hegyi index in low or no-affected stand by windthrow. The variability of the basal area increment (lnΔɡ10), explained by competition indices, is rather low (<2%) in the stand that had been highly affected by windfall, regardless of the selected competition index. Thus, significant reduction of the stand density related to number of trees (low density), as a consequence of high intensity windfalls, crown competition has a very small influence on the basal area increment comparing with situations met in low (high density) and moderate (medium density) affected stands.
Źródło:
Dendrobiology; 2015, 73
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gregarina typographi (Eugregarinorida: Gregarinidae) in the bark beetle Ips typographus (Coleoptera: Curculionidae): transmission in nuptial chambers
Autorzy:
Lukášová, Karolina
Holuša, Jaroslav
Powiązania:
https://bibliotekanauki.pl/articles/763648.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
Beskids, Gregarinidae, horizontal transmission, protozoan disease, spruce bark beetle
Opis:
Changes in Gregarina typographi Fuchs, 1915 (Eugregarinorida: Gregarinidae) infection levels were studied in a population of the bark beetle Ips typographus (L., 1758) (Coleoptera: Curculionidae), which lives in association with Norway spruce. Beetles were repeatedly collected from three logs of trap trees during 2009 and 2010 at one study site in the Czech Republic with a high level of G. typographi infection (seasonal mean of 15.7% in 2009 and 19.8% in 2010). Infection levels did not differ statistically between sexes, logs, and trap trees but did differ among sampling dates. During the beetle reproductive period, the infection levels nearly doubled in 2009 (from 10.7 to 19.8%) and more than tripled in 2010 (from 9.3 to 31.3%). We infer that the continuous increase in the G. typographi infection level within each of the two years resulted from transmission among beetles in nuptial chambers during the May–June reproductive and egg-laying period.
Źródło:
Acta Protozoologica; 2011, 50, 4
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A tree - ring reconstruction of geomorphologic disturbances in cliff forests in the Tatra Mts.
Autorzy:
Zielonka, T.
Dubaj, N.
Powiązania:
https://bibliotekanauki.pl/articles/294903.pdf
Data publikacji:
2009
Wydawca:
Stowarzyszenie Geomorfologów Polskich
Tematy:
cliff forest
dednrochronology
landslide
Norway spruce (Picea abies)
rockfall
Opis:
Geomorphological events are very important disturbance factors for cliff forests and forests located on steep mountain slopes. In this study we present dendrochronological reconstruction of two types of disturbances which affect subalpine forest growing in such extreme habitats in Roztoka Valley in the Tatra Mountains: landslide and rockfalls. We determine the years of death of trees found in landslide area on Czuba Roztocka which indicate the year of 1997 as the time of this event, probably related to heavy midsummer rainfall in this year. Scars on trees growing at the base of Orle Ściany cliff allowed determining the rockfall events. We found that scars, even in neighbour trees were formed in different years between 1940 and 2004. It means that they were formed rather by separate stones which fell from the cliff sporadically then a large scale fall of debris at the same time. This may suggest that rockfalls in cliffs of Orle Ściany were limited to single rocks which fell successively when erosion process separated them from the bedrock. Dendrochronology seems to be an effective method which enables long term reconstruction of gemorphological processes in the High Tatras.
Źródło:
Landform Analysis; 2009, 11; 71-76
1429-799X
Pojawia się w:
Landform Analysis
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monitoring of xylem formation in Picea abies under drought stress influence
Autorzy:
Gryc, V.
Hacura, J.
Vavrcik, H.
Urban, J.
Gebauer, R.
Powiązania:
https://bibliotekanauki.pl/articles/41506.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
monitoring
xylem formation
Norway spruce
Picea abies
drought stress
Opis:
The effect of drought stress on regular cambium activity and wood formation in stems of two different clones of Norway spruce (Picea abies (L.) Karst.) was investigated. Tissue samples were taken during the growing season from May to September 2010. Artificial drought stress, induced by long-term sheltering of the soil, was significantly manifested in clone 15. In the stressed individual, the period of cambium activity was shorter, the total number of formed cells was lower and the resulting tree ring was narrower. The number of cells in the phases of postcambial growth and secondary cell wall formation was significantly lower in comparison to the control tree. The tracheid lignification process was slower in the tree stressed by water deficit and the first mature tracheids were observed later. On the other hand, in clone 18 probably genetic dispositions played an important role as no considerable deviations in the cambium activity and new wood cells production were observed. Fitting xylem increments to the Gompertz function showed that the period of the most intensive cell formation was at the turn of June and July and the maximum daily production of new cells was higher in non-stressed individuals than in the stressed ones. The results of the experiment lead us to the conclusion that drought stress can significantly affect the cambium activity of some clones, the differentiation process of anatomical elements, and thus also the resulting tree ring width.
Źródło:
Dendrobiology; 2012, 67
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ wskaźnika zadrzewienia drzewostanu na wybrane cechy makrostruktury i gęstość drewna świerkowego (Picea abies (L.) Karst.)
Effect of stand density index on selected features of macrostructure and density of Norway spruce (Picea abies (L.) Karst.) wood
Autorzy:
Michalec, K.
Powiązania:
https://bibliotekanauki.pl/articles/978906.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Leśne
Tematy:
tree−ring width
latewood proportion
wood density
Norway spruce
Opis:
The aim of the study was to determine the influence of stand density index on the tree−ring width, latewood proportion and wood density for Norway spruce. Study sites were located as follows: 12 within the north−eastern species range in Poland, 7 in the south−western range, in the Sudety Mts., and 9 in the Carpathians (southern range). Clustering stands according to their stand density index, 10 data groups were established: stand density index values from 0.3 to 1.2. The study plots were 100×100 m squares. On each plot 15 trees were chosen and increment cores were sampled using the Pressler borer. The smoothed cores served for measuring the width of annual rings, latewood zones and the share of latewood as well as for determination of relative wood density. The performed analyses indicate that mean tree−ring width was the highest in trees from stands with density index from 0.3 to 0.8 (with the exception of 0.7), whereas the it was gradually decreasing in stands with index higher than 0.9. The statistically significant differences between the analyzed stands were observed (p<0.0001). The analysis of the influence of stand density index and the width of annual rings revealed significant, negative weak correlation (r=–0.242, p<0.001). In turn, the latewood proportion was the highest in trees from stands characterised by the highest stand density index and the lowest in trees from stands with the lowest one. The differences between analyzed groups of stands were statistically significant (p<0.0001), as well as the correlation which was significant, positive and weak (r=0.269, p<0.001). Wood density was the highest in trees from stands with the highest stand density index (1.1 – 363 kg/m3 i 1.2 – 365 kg/m3) as well as in those from stands characterised by 0.7 density index (369 kg/m3). Significant differences were observed (p<0.0001) only between stand density index 0.3−0.7 and 0.7−0.8. Significant correlation was not observed.
Źródło:
Sylwan; 2020, 164, 09; 719-725
0039-7660
Pojawia się w:
Sylwan
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The radial variation of the selected physical and mechanical properties of Norway spruce (Picea abies (L.) H. Karst) wood from the provenance area in Głuchów
Autorzy:
Zawadzka, Karolina
Kozakiewicz, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2201235.pdf
Data publikacji:
2019
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
Norway spruce
wood density
wood properties
mechanical and physical parameters
Opis:
The radial variation of the selected physical and mechanical properties of Norway spruce (Picea abies (L.) H. Karst) wood from the provenance area in Głuchów. Spruce wood (Picea abies (L.) H. Karst) is one of the main species used in building constructions. Due to the wide occurrence, it is important to test various origins and in this way select those with the best material properties. Wood was obtained from one habitat from a provenance experimental area in Głuchów from 40-year-old trees. For the study, trees from three different origins were selected: Nowe Ramuki, Bliżyn and Rycerka Praszywka II (origin from respectively northern, central and southern Poland - seedlings came from these places). Spruce wood from Bliżyn, which is the closest to the proven research area in Głuchów, reached the highest average values in all studied traits (density, ultrasonic wave velocity, dynamic and static modulus of elasticity and static bending strength) and was characterized by the highest variability of these features. Regardless of the origin, the above-mentioned features of the wood showed a clear upward trend going from the pith to the to the side of the trunk.
Zmienność promieniowa wybranych właściwości fizycznych i mechanicznych drewna świerkowego (Picea abies (L.) H. Karst) z powierzchni proweniencyjnej w Głuchowie. Ze względu na szerokie występowanie świerk pospolity wykazuje znaczną zmienność genetyczną, która może przekładać się również na cechy i właściwości tworzonego drewna, decydujące o przydatności surowca do różnych celów przemysłowych. Badanie przeprowadzono na drewnie pozyskanym z 40-o letniego, litego drzewostanu świerkowego z powierzchni doświadczalnej Leśnego Zakładu Doświadczalnego Rogów w Leśnictwie Głuchów. Poszczególne drzewa, wzrastające w tych samych warunkach, różniły się pochodzeniem. W niniejszej pracy analizowano trzy pochodzenia: po jednym z północnej, centralnej i południowej części Polski, a mianowicie: Nowe Ramuki, Bliżyn i Rycerka Praszywka II. Drewno świerkowe z pochodzenia Bliżyn, leżącego najbliżej proweniencyjnej powierzchni badawczej w Głuchowie, osiągnęło najwyższe średnie wartości we wszystkich badanych cechach (gęstości, prędkości fal ultradźwiękowych, dynamicznego i statycznego modułu sprężystości oraz wytrzymałości na zginanie statyczne)a także charakteryzowało się największą zmiennością tych cech. Niezależnie od pochodzenia wymienione wyżej cechy drewna wykazywały wyraźną tendencję wzrostową idąc od rdzenia do obwodu pnia.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology; 2019, 105; 133--143
1898-5912
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biopolymer composites based on galactoglucomannans (ggms) and micrystaline chitosan (mcch)
Autorzy:
Kopania, Ewa
Wiśniewska-Wrona, Maria
Powiązania:
https://bibliotekanauki.pl/articles/1034988.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Polskie Towarzystwo Chitynowe
Tematy:
biopolymer composites
enzymatic treatment
galactoglucomannans
microcrystalline chitosan
spruce
thermal treatment
Opis:
The article presents a method of extracting galactoglucomannas (GGMs) from softwood (spruce). GGMs were extracted using thermal and enzymatic treatment in an aqueous environment. The extracted GGMs, depending on the extraction method, were characterized by different composition of simple carbohydrates i.e. glucose, galactose and mannose, as well as by the average molecular weight. Evaluation of the composition of GGMs obtained was performed using GC/MS and SEC. Biopolymer composites were obtained by combining GGMs and microcrystalline chitosan (MCCh), which can be used as preparations for plant protection and growth stimulation. The studies were performed in order to evaluate biological activity of composites based on Petri dish test in which their ability to stimulate seed germination of selected plants was estimated. The effect of plant growth stimulation depended on GGMs composition of simple carbohydrates. GC/MS and SEC chromatographic tests and 13C NMR analysis enabled to establish the composition and structural changes of the obtained GGMs and biocomposites
Źródło:
Progress on Chemistry and Application of Chitin and its Derivatives; 2015, 20; 110-121
1896-5644
Pojawia się w:
Progress on Chemistry and Application of Chitin and its Derivatives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality assessment methods for Picea abies seeds
Autorzy:
Prochazkova, Z
Powiązania:
https://bibliotekanauki.pl/articles/41166.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
international conference
Europe
forest ecosystem
plant breeding
tree
Norway spruce
Picea abies
seed quality
purity
germination
health testing
assessment method
spruce seed
Opis:
The quality assessment of spruce seeds consists mainly in determining their germination capacity, including germination rate (speed), but also purity and weight. Internationally recognised methods are listed in the ISTA Rules for Seed Testing which also specify test conditions. Some countries such as Poland use modified methods. Apart from providing information about the purity of a species, purity testing can also identify the proportion of winged seeds in each seed lot. Germination tests yield data on the maximum germination potential of a seed lot which are used to compare the quality of different lots and to establish the field sowing values. This paper presents the methods used for assessing the quality of Norway spruce seeds, and discusses their advantages and disadvantages and the problems that need further investigation.
Źródło:
Dendrobiology; 2009, 61 Supplement
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The dynamics and structure of dead wood in natural spruce-beech forest stand - a 40 year case study in the Krkonose National Park
Autorzy:
Vacek, S.
Vacek, Z.
Bilek, L.
Hejcmanova, P.
Sticha, V.
Remes, J.
Powiązania:
https://bibliotekanauki.pl/articles/41560.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
forest
natural forest
mixed stand
dynamics
structure
dead wood
spruce-beech forest
European beech
Fagus sylvatica
Norway spruce
Picea abies
Czech Republic
Karkonosze National Park
Opis:
The study deals with long-term dynamics of snags and fallen dead wood from 1970 to 2010 in an unmanaged forest ecosystem dominated by European beech in the Bažinky area, Krkonoše National Park (Czech Republic). The volume of dead wood was estimated from 1970 separately for fallen dead wood (logs) and standing dead wood (snags and stumps). Total dead wood volume on permanent research plot (PRP) 6 increased from 41.9 to 241.6 m3 ha–1 and on PRP 7 from 27.7 to 170.0 m3 ha–1. During 40 year case study the mean total volume of fallen dead wood was 193.3 m3 ha–1 (± 29.8 S.E.) and 96.2 m3 ha–1 (± 19.4 S.E.) and the mean total volume of standing dead wood was 17.4 m3 ha–1 (± 3.4 S.E.) and 12.6 m3 ha–1(± 1.4 S.E.) on PRP 6 and PRP 7, respectively. Comparing tree species, the mean volume of fallen dead wood was significantly higher for Norway spruce than for beech in the decomposition class 1 (F(1, 14) = 5.7, P = 0.03) and significantly higher for beech in the decomposition classes 4 (F(1, 14) = 20.4, P < 0.001) and 5 (F(1, 14) = 25.5, P < 0.001). Dead wood was distributed from randomly to aggregated spatial pattern. Despite the rapid decay of beech wood, the amounts of deadwood are likely to increase further during the next decades with continuing disintegration of the forest stand.
Źródło:
Dendrobiology; 2015, 73
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spadek wytrzymałości mechanicznej drewna świerkowego na skutek zniszczeń spowodowanych przez owady
Strength decrease of spruce wood as a result of damage by insects
Autorzy:
Żelazny, H.
Bednarz, B.
Powiązania:
https://bibliotekanauki.pl/articles/362699.pdf
Data publikacji:
2017
Wydawca:
Instytut Fizyki Budowli Katarzyna i Piotr Klemm
Tematy:
drewno świerkowe
wytrzymałość
szkodniki techniczne
spruce wood
strength
xylophage insects
Opis:
W pracy zbadano o ile może zmniejszyć się wytrzymałość mechaniczna drewna świerkowego z powodu zniszczenia tkanki drzewnej przez szkodniki techniczne. W ocenie zginania uzyskano około 1,6-krotne zmniejszenie wytrzymałości drewna uszkodzonego, przy rozciąganiu wzdłuż włókien wytrzymałość doraźna zmalała 1,4 razy, natomiast przy rozciąganiu w poprzek włókien niespodziewanie odnotowano 1,4-krotny wzrost tej wytrzymałości. Badanie próbek na ściskanie wzdłuż włókien pozwoliło stwierdzić, że wytrzymałość drewna zniszczonego przez owady zmalała około dwukrotnie, a przy ścinaniu w poprzek włókien obniżyła się nawet 2,8-krotnie. Uzyskane wyniki potwierdzają znaczne obniżenie się niezawodności konstrukcji drewnianych na skutek zniszczeń struktury materiałowej przez owady, co nie może nie mieć znaczenia w bezpieczeństwie użytkowania obiektów budowlanych.
The purpose of the work was to examine how much it can decrease strength spruce wood damaged by insects. In bending test was obtained about 1,6 times strength reduction of damaged wood. When stretching along the fibers ad-hoc endurance decreased 1,4 times, while at stretching across the fibers unexpectedly detected 1,4 times strength increase. In compression test was obtained about double reduction of ad-hoc strength. On shear across the fibers detected 2,8 times decrease of endurance. Results confirm significant reduction of reliability of wooden constructions as a result of damage by insects, what is important for structural safety.
Źródło:
Fizyka Budowli w Teorii i Praktyce; 2017, T. 9, nr 1, 1; 45-50
1734-4891
Pojawia się w:
Fizyka Budowli w Teorii i Praktyce
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Forest plantation productivity - soil interactions within Western Forest-Steppe of Ukraine: effects of pH and cations
Autorzy:
Raspopina, Svitlana
Debryniuk, Yuriy
Hayda, Yuriy
Powiązania:
https://bibliotekanauki.pl/articles/2041494.pdf
Data publikacji:
2020
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
forest plantation
larch
spruce
oak
potential acidity
absorbed bases
movable aluminium
Opis:
Dark grey podzolized soils on the loess like loams, which are represented in the soil cover within fresh and humidity gradients in the Western Forest Steppe of Ukraine, are characterized by high forest vegetation potential, which ensure the formation of mostly pure and mixed larch and spruce stands with high level of the productivity. Despite the fact that both species are coniferous, their effect on the soil, in particular, on its acid-base indicators (actual and potential forms of acidity, sum of absorbed bases, degree of saturation of bases, content of mobile aluminium), which are important components of soil fertility, are specific. Due to the fact that there is a close interaction between forest plantations and soil properties, changing the participation of species in the stand, it is possible to adjust the actual soil fertility. The soils under both pure and mixed spruce and larch stands are characterized by a high level of potential acidity that reaches the high acidic values in the upper horizons. A similar reaction of soil solution under coniferous forests is caused by acid hydrolysis of aluminosilicates and accumulation of mobile Al in the rhizosphere zone. Simultaneously, the same acidic characteristics, including the presence of movable aluminium, are also found in soils under broadleaved plantations. In general, acid-exchange properties of soils (high potential acidity, unsaturation of bases and availability of movable aluminium) traditionally are considered as unfavourable for vegetation. However, our researches refute it and prove that within certain values, these indicators do not limit the productivity of pure and mixed spruce and larch stands.
Źródło:
Folia Forestalia Polonica. Series A . Forestry; 2020, 62, 4; 233-245
0071-6677
Pojawia się w:
Folia Forestalia Polonica. Series A . Forestry
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Size and localisation of knots in timber from mountain spruce stands in the Dolomites
Autorzy:
Barszcz, A.
Sandak, A.
Sandak, J.
Powiązania:
https://bibliotekanauki.pl/articles/38333.pdf
Data publikacji:
2010
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
size
localization
knot
timber
mountain spruce
tree stand
Dolomites
knot healthiness
Opis:
The aim of the study was evaluation of knots in wood of 150-year-old Norway spruce [Picea abies (L.) Karst.] in stands situated at the altitude of 1450– 1740 m above sea level in the Dolomites in Italian section of the Alps. In selected stands, spruce trees were cut down and their length, stem thickness, height to the crown base and stem diameters at every 1 m along the length of merchantable bole were measured. The diameter of knots was measured and they were classified according to their healthiness and the degree of their tightness with the surrounding wood. The relative knot diameters were calculated and the relative height of their location on stem was determined. In total on sample trees there were analysed 1070 knots, of which sound knots (close to 75%) and tight (more than 60%) prevailed. Sound and tight knots had largest diameters, relative diameters and relative heights of location on merchantable boles. The smallest diameters and relative diameters were indicated by rotten and not tight knots that were located at the lowest merchantable bole parts.
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
Tytuł:
Flowering and cone bearing of Picea abies grafts in second-generation seed orchards
Autorzy:
Misiorny, A
Chalupka, W.
Powiązania:
https://bibliotekanauki.pl/articles/41542.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Norway spruce
Picea abies
cone yield
seed production
flowering
seed orchard
Opis:
In 2004, abundant flowering of Norway spruce (Picea abies (L.) Karst.) was observed in two second- generation seed orchards: (1) ‘Outbreeding’, promoting crossing between clones of five geographically distant populations; and (2) ‘Kolonowskie’, restoring a population whose offspring exists only in an international experiment (IUFRO 1964/1968). In bothseed orchards, female strobili were produced by 91.3% and 91.7% of clones, represented by 64.1% and 55.5% of grafts, respectively, and statistically significant differences between clones were found in the number of mature cones. In the case of the seed orchard ‘Outbreeding’, the number of mature cones in individual clones was significantly correlated with latitude of the origin of maternal populations (r = 0.8826, p = 0.0470). The majority (95%) of cones in seed orchards ‘Outbreeding’ and ‘Kolonowskie’ were produced by only 28.2% and 38.5% of all clones, and 21.4% and 25.7% of all grafts, respectively. These data attest to a disparity between the level of genetic diversity in seed orchard progeny resulting from the observed numbers of cone-bearing clones and grafts and the genetic diversity expected from the actual participation of clones and grafts in seed orchard composition. The estimated seed production per 1 ha of seed orchard area in 2004 reached 21.05 kg for ‘Outbreeding’ and 21.72 kg for ‘Kolonowskie’.
Źródło:
Dendrobiology; 2006, 56; 51-59
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of thermal modification temperature of spruce wood on cutting parameters during circular saw blade cutting
Autorzy:
Hlásková, Luďka
Kopecký, Zdeněk
Novák, Vit
Powiązania:
https://bibliotekanauki.pl/articles/2146674.pdf
Data publikacji:
2021
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
thermal modification
cutting force
specific cutting resistance
circular saw blade
spruce
Opis:
Effect of thermal modification temperature of spruce wood on cutting parameters during circular saw blade cutting. The work examines the effect of temperature on energetical parameters (specific cutting resistance and cutting force) when cutting heat-treated wood of Norway spruce (Picea Abies) by a circular saw. The test samples were heat-treated at 160°C, 180°C, 200°C and 220°C. One sample was not heat treated and was used as a reference sample. In comparison with the theoretical assumptions, the influence of temperature on the cutting force and specific cutting resistance was confirmed. With increasing temperature of modification, the specific cutting resistance and cutting force decreased. The reduction of value of cutting force is related to changes in the chemical structure of the wood components, weight and density loss due to the increasing temperature of modification.
Wpływ temperatury modyfikacji termicznej drewna świerkowego na parametry skrawania podczas cięcia piłą tarczową. W pracy zbadano wpływ temperatury modyfikacji na parametry skrawania (oprór skrawania i siła skrawania) przy cięciu piłą tarczową drewna świerka pospolitego (Picea Abies) poddanego obróbce termicznej. Próbki drewna do badań poddano obróbce w temperaturze 160°C, 180°C, 200°C i 220°C. Jako wariant kontrolny wykorzystano drewno naturalne (nie poddane obróbce termicznej). W ramach badan potwierdzono wpływ temperatury modyfikacji na siłę skrawania i opory skrawania drewna. Wraz ze wzrostem temperatury modyfikacji zmniejszały się wartosci oporu skrawania i siły skrawania. Zmniejszenie wartości siły skrawania związane jest ze zmianami struktury chemicznej składników drewna, ubytkiem masy i gęstości pod wpływem wzrostu temperatury modyfikacji.
Źródło:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology; 2021, 113; 30--35
1898-5912
Pojawia się w:
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 16-30 z 214

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