Wyniki wyszukiwania - Biblioteka Nauki

1

Response of greenhouse tomato to increased plant densities and defoliation

100%

Miszalski Z. , Mydlarz J. , Libik A.

Bulletin of the Polish Academy of Sciences. Biological Sciences

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1989

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tom 37

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nr 4-6

2

Application of aerial hyperspectral images in monitoring tree biophysical parameters in urban areas

100%

Jarocińska A. , Białczak M. , Sławik Ł.

Miscellanea Geographica. Regional Studies on Development

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2018

|

tom 22

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nr 1

EN

Monitoring of trees in urban areas can be conducted using remote sensing, but should be supported by field measurements. The article aims to present the research method used to evaluate discolouration and defoliation of trees and tree damage in the city of Białystok in Poland. The analyses were done using AISA hyperspectral images. Field measurements encompassed determining the locations, species and levels of discolouration and defoliation of trees. Remote sensing indices of vegetation were calculated and correlated with the field-measured values of discolouration and defoliation. Based on that, values of discolouration and defoliation were calculated and evaluated against the field studies. The RMSE of the acquired data was around 16%. Using parameter values, a map of tree damage was drawn up. Based on the analysis, it can be stated that a significant number of trees is undamaged, although a large portion of the trees falls into the warning class.

3

Scots pine (Pinus sylvestris L.) crown condition in the Lubin Forest District (Wroclaw RDSF) in years 2002-2004

86%

Jaszczak R. , Niziolek K. , Przybylski P.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

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2007

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tom 06

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nr 3

4

Improved methods of classification of multispectral aerial photographs: evaluation of floodplain forests in the inundation area of the Danube

86%

Bucha T. , Slavik M.

Folia Forestalia Polonica. Series A . Forestry

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2013

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tom 55

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nr 2

EN

The Gabčíkovo hydroelectric power plant has significantly influenced Danube water regime, thus the condition of floodplain forests in the region. Forest condition has been regularly monitored since 1995 using aerial photos. The subject of this study was to improve the procedure of floodplain forest health evaluation based on digital multispectral aerial images. Firstly, the forest mask was created with overall accuracy 89%, and next, tree health was evaluated using defoliation as health indicator. We applied orthogonal transformation of 4 original bands of multispectral imagery into two-dimensional space. Marginal values of digital numbers (DN) of the first component (New Synthetic Channel – NSC1) were defined by fully foliated willow and poplar. The second component (NSC2) was optimised for damage estimation. Calculated DN values of NSC2 represented a perpendicular distance from the line of DN values of the first component. The distance from the line was proportionate to tree damage extent in a given pixel. We generated linear regression model between pair values of NSC2 and defoliation evaluated for 38 trees in the field, respectively, from aerial photos. A decline prediction resulted in r-square equal 0.86. Finally, we used the model to predict defoliation for each picture element (pixel) of the component NSC2.

5

The study of the causal agents of massive needle fall in blue spruce

86%

Werner M. , Fruzynska-Jozwiak D. , Andrzejak R.

Roczniki Akademii Rolniczej w Poznaniu. Ogrodnictwo

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2001

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tom 34

6

Evaluation of oak tree conditions on the basis of losses in the assimilation aparatus of selected oak stands in Sulecin Forest District

72%

Szewczyk W. , Dudek M. , Baranowska M.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

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2011

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tom 10

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nr 3

EN

Oak trees play a significant naturalistic and economic role. Common oaks represent the most valuable forest-creating species in Poland. In the recent years, on the area of the whole country, one can observe a visible deterioration of the health conditions in oak tree stands. It is difficult to indicate the main factor responsible for this phenomenon. Because of the wide range of this observation, it can be assumed that this process is caused by many biotic and abiotic, as well as anthropogenic factors. Studies were out in the Sulęcin Forest District. At the turn of July and August in the years 2009 and 2010, an assessment of the losses in the majority of trees showed a medium degree (49%). Another group of trees showed 36% of leaf loss, while 14% of oak trees did not show any losses at all. A very high degree of defoliation was found only in 1% of trees. The presented data indicate that an average loss in the assimilation apparatus of oak trees amounted to 29.15%.

PL

Dęby mają duże znaczenie gospodarcze i przyrodnicze. Dąb szypułkowy jest najcenniejszym gatunkiem lasotwórczym w Polsce. W ostatnich latach na terenie całego kraju obserwujemy widoczne pogorszenie kondycji zdrowotnej drzewostanów dębowych. Trudno jest znaleźć jeden główny czynnik odpowiedzialny za to zjawisko. Ze względu na tak szeroki zasięg jego występowania przyjmuje się, że na ten proces składa się wiele czynników abiotycznych, biotycznych oraz antropogenicznych. Badania zostały przeprowadzone w Nadleśnictwie Sulęcin. Na przełomie lipca i sierpnia w 2009 oraz 2010 roku przeprowadzono ocenę ubytku aparatu asymilacyjnego dębów. Analiza stanu zdrowotnego dębów wykazała, że w większości drzewa były w średnim stopniu defoliacji - 49%, następnie 36% stanowiły drzewa z lekką defoliacją, 14% drzew nie wykazało uszkodzeń, natomiast 1% obejmuje drzewa z dużą defoliacją. Z przedstawionych danych wynika, że średnia wartość ubytku aparatu asymilacyjnego to 29,15%.

7

Method of external assessment of the quality of sugar beet roots

72%

Przybył J. , Mioduszewska N. , Wojcieszak D. , Durczak K. , Ożańska E.

Inżynieria Rolnicza

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2013

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tom R. 17, nr 4, t. 2

113--125

EN

The research problem of the paper concerned verification whether applicable or known methods of post-harvesting evaluation of the roots of sugar beet may be applied to the assessment of the quality of work of technically varied new machinery for sugar beet harvesting. Tests of machines of varied solutions of working units, in particular a topping unit, were carried out in order to accomplish the objective of the paper. Two self-propelled combine harvesters of Ropa euro-Tiger V8-3 type and Kleine Beetliner Large and two sets for 2-stage harvesting by M.A.C.E (Spain) and Amity (USA) companies were used in the study. Ropa euro-Tiger and Kleine Beetliner Large combine harvesters and M.A.C.E. set were equipped with a beet topper but of a varied topping system, whereas, only a defoliator was used in the set by Amity company. Field research of machines included assessment of the topping quality, losses caused by the broken tip of roots and damages of the lateral surface of roots. Research assumptions were assumed according to the method of the International Institute for Beet Research (I.I.R.B.). Moreover, assessment of the topping quality with the method of the Netherlands Institute of Sugar Beet Research (IRS) and the Institute of Agricultural Engineering of the Bonn University was carried out. Assessment of roots after defoliation was carried out based on the Roller's classification (2010). Based on the research results and analyses which were carried out, it was proved that the methods of measurement of the quality of beet harvesting machines operation are not fully useful for assessment of the introduced technical and technological changes. It mainly concerns the assessment of the roots topping. Thus, two modified methods of assessment of the quality of roots topping were suggested. They may be used both for machines equipped with a topping device and a defoliator.

PL

Problem badawczy pracy dotyczył sprawdzenia, czy obowiązujące lub znane metody oceny pozbiorowej jakości korzeni buraka cukrowego można stosować do oceny jakości pracy zróżnicowanych technicznie nowych maszyn do zbioru buraków cukrowych. Dla zrealizowania celu pracy przeprowadzono badania maszyn o zróżnicowanych rozwiązaniach zespołów roboczych, a w szczególności zespołu ogławiającego. Do badań wyznaczono dwa kombajny samojezdne typu Ropa euro-Tiger V8-3 i Kleine Beetliner Large oraz dwa zestawy do zbioru 2-etapowego firm M.A.C.E. (Hiszpania) i Amity (USA). Kombajny Ropa euro-Tiger i Kleine Beetliner Large oraz zestaw M.A.C.E. były wyposażone w ogławiacz, ale o różnym rozwiązaniu dogławiacza, natomiast w zestawie firmy Amity zastosowano wyłącznie defoliator. Badania polowe maszyn obejmowały ocenę jakości ogłowienia, strat spowodowanych obłamanym końcem korzeni oraz uszkodzeń powierzchni bocznej korzeni. Założenia badawcze przyjęto zgodnie z metodą Międzynarodowego Instytutu Buraka Cukrowego (I.I.R.B.). Wykonano również ocenę jakości ogłowienia metodą Holenderskiego Instytut Buraka Cukrowego (IRS) oraz Instytutu Inżynierii Rolniczej Uniwersytetu w Bonn. Ocenę korzeni po defoliacji przeprowadzono na podstawie klasyfikacji Rollera (2010). Na podstawie wyników badań i przeprowadzonych analiz wykazano, że stosowane obecnie metody pomiaru jakości pracy maszyn do zbioru buraków nie są w pełni przydatne do oceny wprowadzanych zmian technicznych i technologicznych. Dotyczy to przede wszystkim oceny ogłowienia korzeni. Dlatego zaproponowano dwie zmodyfikowane metody oceny jakości ogłowienia korzeni, które można zastosować zarówno do maszyn wyposażonych w ogławiacz, jak i defoliator.

8

Biomass allocation, compensatory growth and internal C/N balance of Lolium perenne in response to defoliation and light treatments

72%

Wang L. , Wang J. , Liu W. , Gan Y. , Wu Y.

Polish Journal of Ecology

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2016

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tom 64

|

nr 4

EN

Light environments can have a considerable influence on how plants respond to defoliation through influencing the biomass allocation patterns and internal C/N ratio. Seedlings of Lolium perenne, a common perennial grass species, were grown for eight weeks under three different light environments (natural light, red light and shading) and two different defoliation treatments (no defoliation versus 50% aboveground biomass removal). This study was conducted to examine (1) the effects of light regimes and defoliation on biomass accumulation, biomass allocation and internal C/N ratio status in plants; (2) how the light regimes influence the pattern of compensatory growth after defoliation; and (3) the relationship between compensatory growth and the internal C/N ratio status. We found that red light altered the shoot-to-root allometry, enhanced the leaf C concentrations and induced N deficiency. By contrast, the leaf N concentrations of L. perenne were greater during shading treatment, which simultaneously enhanced shoot growth and stopped root growth. Under defoliation, red light increased shoot growth, not at the expense of root growth, which was not the same as in natural light and shading treatment. Moreover, regardless of the unclipped (no defoliation) and defoliation conditions, the L. perenne biomass partitioning between roots and shoots was significantly correlated with the leaf N concentrations and C/N ratio, indicating that allometric biomass allocation can be largely modulated by signals related to the C and N status of the plants. These results demonstrated that the leaf C and N status would be an appropriate indicator of compensatory growth after defoliation.

9

Vitality of European beech (Fagus sylvatica L.) at the limit of its natural range in Poland

72%

Dobrowolska D.

Polish Journal of Ecology

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2015

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tom 63

|

nr 2

EN

The European beech is a major component of central European forests, and the eastern limit of its range lies in Poland. However, the Holocene migration of the beech is not yet finished, especially in NE Poland, so the northern distribution of the beech continues to change. The main goal of this study was to determine if the beech will reach its northern limit in the future. The investigation was carried out in 18 beech stands in Poland. To study the status of the health of the trees, circular plots were established in grids of different sizes. The basal beech stand area ranged from 3.7 m² ha⁻¹ to 31.2 m² ha⁻¹. The density of trees exceeded a hundred trees per hectare in most of the plots (61%), and the average degree of defoliation was not greater than 60% in all of the investigated stands. Environmental conditions influenced defoliation of beech trees (Fisher's test, F = 4.0204; P <0.0001). The vitality of the beech trees varied between stands (Kruskal-Walis test, H = 139.7433, P <0.0001) and was rather good in 56% of the study plots. Seedlings and saplings were observed in all of the investigated stands, and they covered from 5 to 39% and 21 to 80% of the study plots, respectively. Spontaneous beech regeneration was widespread and differed from stand to stand as well as within stands in all of the study plots. The number of tall seedlings in most of the study plots (56%) was greater than 10,000 individuals per hectare. The factors limiting beech regeneration were stand density and herb cover, and the number of beech seed trees influenced the quantity of small seedlings. Beech tree density positively influenced the number of small seedlings, and the strength of the correlation was moderate and statistically significant (Pearson correlation, r = 0.349). Beech tree density influenced the vitality of tall and small saplings (Pearson's correlations, r = 0.673 and r = 0.361, respectively). The spontaneous regeneration and strong vitality of seedlings and saplings suggests that beech can create stable stands in the future and that it is an expansive tree species both within its continuous range and at the limit of its distribution. It is quite possible that beech will reach its north-eastern limit in Poland in the future.

10

Application of a synthetic tree damage index to assess changes in the health condition of selected oak stands in the Wloszakowice Forest Division

72%

Kuzminski R. , Wtyklo R.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

|

2014

|

tom 13

|

nr 2

EN

The paper presents an evaluation of health condition of selected oak stands in the Włoszakowice Forest Division based on a synthetic tree damage index. Field work was conducted in 2007-2008. In order to perform this task seven experimental sites were established, with 25 trees from Kraft’s age classes I-III evaluated in each. It was found that the overall health condition of most stands deteriorated in 2008 in comparison to 2007.

PL

Obserwowane od wielu lat pogorszenie stanu zdrowotnego drzewostanów dębowych stwarza konieczność monitorowania tego zjawiska. W ocenie drzewostanów powszechnie wykorzystywana jest wielkość defoliacji. Jednak jako czynnik bardzo zmienny w czasie, uzyskiwane wyniki mogą nie w pełni oddawać stan faktyczny. Dlatego proponuje się wykorzystać metodę opartą na witalności drzew i procentowym ubytku aparatu asymilacyjnego do oceny stanu zdrowotnego drzew i drzewostanów [Dmyterko i Bruchwald 1998]. Celem pracy było zbadanie przydatności proponowanej metody do oceny stanu zdrowotnego drzewostanów dębowych i określenia wielkości tych zmian. Praca została zrealizowana na terenie Nadleśnictwa Włoszakowice w latach 2007-2008. Stwierdzono, że ogólny stan zdrowotny większości drzewostanów pogorszył się w 2008 roku w porównaniu z 2007 rokiem. Dla większości z nich zmiana nie była istotna, na dwóch powierzchniach stwierdzono jednak większy ubytek aparatu asymilacyjnego niż w roku bazowym – co skutkowało obniżeniem kategorii zdrowotności. Z przeprowadzonych badań wynika, że syntetyczny wskaźnik uszkodzenia drzew jest wygodnym narzędziem do monitorowania stanu zdrowotnego drzew i drzewostanów. Jest bardziej stabilny, niż sam czynnik defoliacji i pozwala obserwować wielkość i kierunek zachodzących zmian.

11

Crown defoliation of trees of common pine [P.sylvestris L.] of different kraft classes in the evaluation of forest health condition

72%

Jaszczak R.

Forestry

|

1999

|

tom 02

12

Tree crowns condition of the main scots pine [Pinus sylvestris L.] tree stand in some selected forest division in 2003

72%

Jaszczak R. , Golojuch P.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

|

2004

|

tom 03

|

nr 2

13

Wpływ typu podszytu na teledetekcyjny pomiar defoliacji Quercus robur L. w zakresie 640-820 nm

58%

Kotlarz J. , Kacprzak M. , Rotchimmel K. , Tkaczyk M.

Pomiary Automatyka Robotyka

|

2018

|

tom R. 22, nr 1

5--10

PL

Jednym z objawów zamierania drzewostanów dębowych w Europie jest wysoka defoliacja obserwowana u drzew o słabej zdrowotności. Na potrzeby corocznego monitoringu dotkniętych patogenem Phytophtora powierzchni badawczych projektu HESOFF w Zakładzie Teledetekcji Instytutu Lotnictwa podjęto próbę wytworzenia metodyki oceny defoliacji za pomocą lotniczych zdjęć wielospektralnych. W tym celu w lipcu 2015 r. za pomocą Platformy Wielosensorowej QUERCUS.6 wykonano zdjęcia lotnicze badanego kompleksu leśnego (zakres 0,46–0,82 μm). Na podstawie zdjęć wykonano pomiar reflektancji dla każdego z badanych dębów oraz porównano pozyskane w ten sposób dane radiometryczne z ocenionym metodą tradycyjną poziomem defoliacji. Na podstawie uzyskanych korelacji wykazano, że pomiar defoliacji jest możliwy przy zastosowaniu kanałów optycznych: 0,46–0,52 μm oraz 0,67–0,82 μm. Wykazano ponadto, że do poprawnego pomiaru defoliacji zaproponowaną w tym artykule metodą, konieczne jest uwzględnienie typu podszytu, który ma decydujący wpływ na obserwowaną reflektancję.

EN

One of the symptoms of dieback of oak stands in Europe is high defoliation, observed in trees with poor health. For the purposes of annual monitoring (in research project HESOFF) of the research area affected by the pathogen Phytophthora, in the Remote Sensing Department of Institute of Aviation was made attempt to develop a proper methodology for defoliation evaluation with multispectral aerial images use. For this purpose in July 2015 with the use of the Multisensory Platform QUERCUS.6 aerial photos of the test forest complex were made (range: 0.46–0.82 μm). Based on the photos, reflectance measurements for each of investigated oaks were made and acquired parameters have been compared with defoliation level obtained by conventional methods. Based on these correlation has been demonstrated that defoliation measurement is possible with use of optical channels: 0.46–0.52 μm and 0.67–0.82 μm. It was also shown that for correct defoliation measurement with proposed in this article methodology it is necessary to take into account the type of underbrush, which has a decisive influence on the observed reflectance.

14

Wplyw stresu mechanicznego na wymiane gazowa oraz wzrost roslin rzodkiewki zwyczajnej i rzepaku jarego

58%

Blamowski Z. K. , Michalek W. , Rukasz I.

Acta Scientiarum Polonorum. Hortorum Cultus

|

2003

|

tom 02

|

nr 1

3-11

EN

The effect of mechanical stress (partial defoliation and/or shoot decapitation) were studied on gas exchanges and growth of radish and rapeseed plants. Removal of older leaves increased transpiration rate (E) but it didn’t have any influence on net photosynthesis rate (Pn). Shoot decapitation and defoliation of young leaves didn’t influence the Pn of radish but it greatly decreased photosynthesis rate of rapeseed plants. The stress also changed pattern of assimilates distribution and the organs’ growth. In radish plants photoassimilates were translocated to hypocotyls whereas in rapeseed they were mostly used for the growth of leaves and roots. It is concluded that mechanical stress plays important role in sink/source regulation. In this way it has an influence on gas exchange, biomass distribution and the growth of plants. That processes also depend on the types (donor or acceptor) and age of defected organs and plants cultivars.

PL

Badano wpływ stresu mechanicznego (częściowej defoliacji lub defoliacji i dekapitacji pędu) na wymianę gazową oraz wzrost roślin rzodkiewki i rzepaku jarego będących w fazie rozety. Usuwanie starszych liści zwiększało intensywność transpiracji (E), ale nie miało wpływu na intensywność fotosyntezy netto (Pn). Dekapitacja pędu i defoliacja młodych liści nie wpływała na intensywność Pn rzodkiewki, ale bardzo silnie obniżała Pn roślin rzepaku. Stres zmieniał także wzór dystrybucji asymilatów. W roślinach rzodkiewki asymilaty translokowane były przede wszystkim do hypokotyla, natomiast u rzepaku wykorzystywane były na wzrost liści i korzeni. Uzyskane wyniki świadczą, że stres mechaniczny odgrywa ważną rolę w regulacji stosunku donory/akceptory asymilatów. Wpływa w ten sposób na przebieg wymiany gazowej, dystrybucję asymilatów oraz wzrost roślin. Wszystkie te procesy zależą dodatkowo od rodzaju (donor czy akceptor asymilatów) i wieku uszkodzonych organów oraz od gatunku roślin.

15

Wplyw pozycji biosocjalnej i wieku drzew sosny zwyczajnej [Pinus sylvestris L.] na defoliacje ich koron w strefie uszkodzen slabych

58%

Jaszczak R. , Jankowski P. , Maliszak L.

|

nr 1

27-45

16

Charakterystyka defoliacji korony drzew sosny zwyczajnej [Pinus sylvestris L.] roznych klas biosocjalnych

58%

Jaszczak R.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

|

2002

|

tom 01

|

nr 2

13-24

17

Biomass Allocation, Compensatory Growth and Internal C/N Balance of Lolium perenne in Response to Defoliation and Light Treatments

58%

Wang L. , Wang J. , Liu W. , Gan Y. , Wu Y.

Polish Journal of Ecology

|

2016

|

tom Vol. 64, nr 4

485--499

EN

Light environments can have a considerable influence on how plants respond to defoliation through influencing the biomass allocation patterns and internal C/N ratio. Seedlings of Lolium perenne, a common perennial grass species, were grown for eight weeks under three different light environments (natural light, red light and shading) and two different defoliation treatments (no defoliation versus 50% aboveground biomass removal). This study was conducted to examine (1) the effects of light regimes and defoliation on biomass accumulation, biomass allocation and internal C/N ratio status in plants; (2) how the light regimes influence the pattern of compensatory growth after defoliation; and (3) the relationship between compensatory growth and the internal C/N ratio status. We found that red light altered the shoot-to-root allometry, enhanced the leaf C concentrations and induced N deficiency. By contrast, the leaf N concentrations of L. perenne were greater during shading treatment, which simultaneously enhanced shoot growth and stopped root growth. Under defoliation, red light increased shoot growth, not at the expense of root growth, which was not the same as in natural light and shading treatment. Moreover, regardless of the unclipped (no defoliation) and defoliation conditions, the L. perenne biomass partitioning between roots and shoots was significantly correlated with the leaf N concentrations and C/N ratio, indicating that allometric biomass allocation can be largely modulated by signals related to the C and N status of the plants. These results demonstrated that the leaf C and N status would be an appropriate indicator of compensatory growth after defoliation.

18

Shea (Vitellaria paradoxa C.F. Gaertn.) seedlings showed impressive recovery after defoliation

58%

Ugese F. D. , Ezechukwu P. T. , Ogbaje C.

International Letters of Natural Sciences

|

2015

|

tom 37

EN

Experiments to determine the effect of seed size, watering interval and defoliation on growth and dry matter attributes of seedlings of shea butter tree were conducted at Makurdi, Nigeria, from July 2010 to April, 2012. In the first experiment, treatments were made up of three seed size categories described as small (5-10g), medium (11-15g) and large (16-20g) and three watering intervals of 3, 6 and 9 days. In the second experiment, treatments comprised three watering intervals of 3, 6 and 9 days and three levels of defoliation – 0, 50 and 100%. In both experiments, factorial combinations of the treatments were laid out in completely randomized design (CRD) and replicated three times. Results of analysis of variance showed that in the first experiment seed size significantly influenced root length with the medium and large seeds producing seedlings with comparatively longer roots than the small seeds. The most frequently watered seedlings (3 and 6 days) produced more leaves than those watered less frequently (9 days). Seed size influenced dry weight of root and total (whole plant) dry weight with the medium and large seeds recording significantly higher values than the small seeds. Watering interval however did not significantly influence any of the other traits. Seed weight exerted significant influence on amount of dry matter partitioned to the stem and the root. More dry matter was partitioned to the stem by the small seeds. Conversely, medium and large seeds allocated more dry matter to the root than to the stem. In the second experiment, defoliation level only influenced total fresh weight, dry weight of root and total dry weight in favour of plants with half their leaves removed. None of the traits examined were significantly influenced by watering regime. Interaction between defoliation level and watering regime significantly influenced total fresh weight, dry weight of root and total dry weight. Generally seed size had more influence on seedling characters than watering interval. Seedlings also demonstrated remarkable ability to overcome effects of defoliation.

19

Zmiana stanu koron sosny zwyczajnej [Pinus sylvestris L.] w Nadlesnictwie Doswiadczalnym Siemianice

58%

Jaszczak R.

Acta Scientiarum Polonorum. Silvarum Colendarum Ratio et Industria Lignaria

|

2002

|

tom 01

|

nr 1

35-43

20

Effect of canopy density on the defoliation of the European silver fir (Abies alba Mill.) due to heavy industrial pollution

58%

Filipiak M. , Napierala-Filipiak A.

Dendrobiology

|

2009

|

tom 62

17-22

EN

Until recently, the level of industrial air pollution in the Sudetes (a mountain range extending on the Czech Republic and Poland border) was very high.This caused a large-scale forest decline, especially in the western part of the Polish Sudetes: in the Izerskie and Karkonosze Mts. An analysis of data on fir defoliation in that area, collected directly after the period of heavy industrial pollution, showed a clear dependence of the degree of defoliation of the primary crown on canopy density: the lower the density, the higher the degree of defoliation.