Template-Type: ReDIF-Article 1.0
Author-Name: V. V. Podrázský
Author-Workplace-Name: Faculty of Forestry and Environment, Czech University of Agriculture in Prague, Prague, Czech Republic
Author-Name: J. Remeš
Author-Workplace-Name: Faculty of Forestry and Environment, Czech University of Agriculture in Prague, Prague, Czech Republic
Title: Changes in humus forms in gaps of the canopy of semi-natural beech stand
Abstract: The article presents original results of research on the humus form dynamics in a semi-natural European beech stand in the National Natural Reserve Voděradské bučiny, in the area of Training Forest Enterprise at Kostelec nad Černými lesy (Czech University of Agriculture inPrague). The accumulation and soil chemical characteristics of particular humus forms were studied: dry matter amount, pH, soil adsorption and exchangeable acidity characteristics as well as plant available and total nutrient contents. The humus form samples were taken in four replications from the particular humus form layers (L, F, H, Ah), and the analyses were performed individually. Samplings were done in the parts of the stand with closed canopy, and they were compared with the state in gaps formed during natural and semi-natural forest regeneration (the stage of stand breaking up left to spontaneous development). The results confirmed marked changes in the quantity and quality of surface humus in the gaps. The amount of dry matter decreased by ca. 25% several years after canopy opening, especially in the H horizon, the pH, base content and base saturation increased, as well as the content of macronutrients (with the exception of total calcium). The results proved considerable changes in the humus forms during the natural and semi-natural forest cycles connected with the stand regeneration.
Keywords: humus forms, beech stands, humus accumulation, soil chemistry, beech regeneration, semi-natural forests
Journal: Journal of Forest Science
Pages: 243-248
Volume: 52
Issue: 6
Year: 2006
DOI: 10.17221/4507-JFS
File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4507-JFS.html
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Handle: RePEc:caa:jnljfs:v:52:y:2006:i:6:id:4507-JFS

Template-Type: ReDIF-Article 1.0
Author-Name: J. Bąk
Author-Workplace-Name: Institute of Biology, Świętokrzyska Academy in Kielce, Kielce, Poland
Title: The occurrence of Megastigmus pictus (Förster) (Hymenoptera: Torymidae) and Resseliella skuhravyorum Skrzypcz. (Diptera: Cecidomyiidae) in the Chełmowa Góra forest reserve of theŚwiętokrzyskiNational Park (Poland)
Abstract: A study conducted in 1999-2000 in 6 compartments of the Chełmowa Góra forest reserve, situated in the ŚwiętokrzyskieMountains, was aimed at harmful insects infesting cones and seeds of Larix decidua Mill. subsp. polonica (Racib.) Domin. Insect rearing and seed and cone cutting yielded 1,045 specimens of insects belonging to 8 species. Resseliella skuhravyorum Skrzypcz. (Diptera: Cecidomyiidae) and Megastigmus pictus (Förster) (Hymeno-ptera: Torymidae) were the most abundantly represented species. They were present in cone samples of all investigated trees. The index of infestation of cones by insects (WZS) was higher in the case of trees growing at the forest edge. The analysis by cutting showed an insignificant percent increase - 6.7% of sound seeds while 88.9% of seeds were blind. M. pictus damaged 2.6% of larch seeds, while R. skuhravyorum 1.7%. The parasitoid Mesopolobus zetterstedtii (Dalla Tore) was received from the mass rearing where its host is M. pictus.
Keywords: insects infesting cones and seeds, larch, Świętokrzyski National Park
Journal: Journal of Forest Science
Pages: 249-254
Volume: 52
Issue: 6
Year: 2006
DOI: 10.17221/4508-JFS
File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4508-JFS.html
File-Format: text/html
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Handle: RePEc:caa:jnljfs:v:52:y:2006:i:6:id:4508-JFS

Template-Type: ReDIF-Article 1.0
Author-Name: J. Urban
Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry Brno, Brno, Czech Republic
Title: Occurrence, bionomics and harmfulness of Chrysomela populi L. (Coleoptera, Chrysomelidae)
Abstract: In 2003 to 2005, Chrysomela populi L. gradated on yearly cut Populus nigra var. italica in street alleys in Brno and elsewhere. Imagoes occurred on trees from the end of April or from the beginning of May. In rearing, the chrysomelid consumed unwillingly leaves of 2-year shoots and laid on average 142 eggs. On leaves of shoots, imagoes damaged 100 to 200 cm2 during 5 to 7 weeks, produced 480 to 900 frass pellets and laid on average 506 eggs. Oviposition was continual with breaks amounting to on average 2.6 days. Embryonal development took 6 to 8 (in the laboratory 5) days. Larvae of the 1st generation occurred from mid-May to mid-July. In the course of 2 weeks (in the laboratory during 10 days) of life, they damaged about 20 cm2 leaves and produced about 300 frass pallets. In the laboratory, prepupae took 2 days and pupae 4 days. Imagoes of the 1st generation occurred from June to September. They damaged on average 113 cm2 and produced on average 553 frass pellets and 653 eggs. At a temperature of 24 to 28°C, imagoes damaged on average 84 cm2 during 2 to 3 weeks and diapaused until the next year. On growing up leaves, imagoes lived longer showing higher consumption of food and higher fecundity as against new fully-grown leaves. Larvae of the 2nd generation destroyed on average 2 cm2 smaller area than larvae of the 1st generation. Part or all imagoes of the 2nd generation diapaused. Imagoes of the 3rd generation damaged 40 to 70 cm2 leaves before departure to wintering grounds. In our natural conditions, the prospective 3rd generation is always incomplete. Cleonice callida Meig. and Schizonotus sieboldi (Ratz.) rank among important enemies.
Keywords: Chrysomelidae, Chrysomela populi, occurrence, host tree species, bionomics, generation conditions, natural enemies, harmfulness
Journal: Journal of Forest Science
Pages: 255-284
Volume: 52
Issue: 6
Year: 2006
DOI: 10.17221/4509-JFS
File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4509-JFS.html
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Template-Type: ReDIF-Article 1.0
Author-Name: P. Král
Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry Brno, Brno, Czech Republic
Author-Name: J. Hrázský
Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry Brno, Brno, Czech Republic
Title: Effects of different pressing conditions on properties of spruce plywoods
Abstract: The paper presents results of an institutional research aimed at assessing the effect of different technological conditions in pressing on physical and mechanical properties of plywood sheets. Spruce plywood sheets of the veneer nominal thickness of 3.0 and 3.5 mm were analyzed. The plywood sheets were produced as five-ply and BAKELITE PF B118 phenol-formaldehyde adhesives were used for there manufacture. In relation to a different pressing temperature 115, 120 and 125°C and a different specific pressure, density, bending strength, MOE in bending and glue-bond strength by a shear test were assessed. The determined values of properties were statistically tested.
Keywords: plywood, plywood density, bending strength, MOE in bending, pressing temperature, statistic analysis
Journal: Journal of Forest Science
Pages: 285-292
Volume: 52
Issue: 6
Year: 2006
DOI: 10.17221/4510-JFS
File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4510-JFS.html
File-Format: text/html
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Handle: RePEc:caa:jnljfs:v:52:y:2006:i:6:id:4510-JFS