Template-Type: ReDIF-Article 1.0 Author-Name: M. Křepela Author-Workplace-Name: Faculty of Forestry and Environment, Czech University of Agriculture in Prague, Prague, Czech Republic Author-Name: R. Petráš Author-Workplace-Name: National Forest Centre - Forest Research Institute Zvolen, Zvolen, Slovak Republic Title: Comparison of Norway spruce (Picea abies [L.] Karst.), Scots pine (Pinus sylvestris L.) and European larch (Larix decidua Mill.) stem shape by means of geometrical methods Abstract: In this article the stem shape is compared in three coniferous tree species: Norway spruce, Scots pine and European larch. Stem is investigated by means of geometrical methods. Simplified Bookstein coordinates (stem shape diameters) and Procrustes coordinates were used for variability investigation. The material, originating from the Czech and Slovak territories, involved in total 3,346 spruce stems, 3,082 pine stems and 1,403 larch stems. The accordance of mean stem vectors was assessed by means of Hotelling's T2 two-sample test. For stem shape diameters and Procrustes tangent coordinates, the variability was examined using the method of principal components analysis. The three most important principal components were diagrammatized and described. The relationship between the stem shape and its size was also investigated, and inflection points of morphological stem curve were described for all three tree species. Keywords: Norway spruce, Scots pine, European larch, stem shape, stem shape diameters, Procrustes coordinates, principal components analysis Journal: Journal of Forest Science Pages: 337-347 Volume: 52 Issue: 8 Year: 2006 DOI: 10.17221/4516-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4516-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-200608-0001.txt Handle: RePEc:caa:jnljfs:v:52:y:2006:i:8:id:4516-JFS Template-Type: ReDIF-Article 1.0 Author-Name: E. Kula Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry Brno, Brno, Czech Republic Author-Name: I. Buchta Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry Brno, Brno, Czech Republic Author-Name: P. Stránský Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry Brno, Brno, Czech Republic Title: Frost cracks and their effect on the stability of birch stands in the Krušné hory Mts. Abstract: Frost cracks which originated in birch due to bending during long-term icing in winter 1995/1996 became the place of entrance for the attack of birch stems by Piptoporus betulinus (Bull. ex Fr.) Karst. and subsequently for one of the causes of birch stand disintegration in the Krušné hory Mts. The hypothesis is substantiated on the basis of regularities of the frost crack dispersion in the stem profile, frequency of occurrence related to the stand age, altitude and cardinal points. The number of frost cracks increased with the transect profile altitude 700-850 m. One crack on the birch stem predominated (73%) while the higher number of frost cracks occurred at altitudes > 800 m. In stands younger than 20 years, frost crack damage was higher (34-47%) than in older stands (14%). Frost cracks occurred in the lower part of stems with the highest bending stress. Keywords: Betula pendula Roth, frost cracks, icing, Piptoporus betulinus (Bull. ex Fr.) Karst., Krušné hory Mts Journal: Journal of Forest Science Pages: 348-356 Volume: 52 Issue: 8 Year: 2006 DOI: 10.17221/4517-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4517-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-200608-0002.txt Handle: RePEc:caa:jnljfs:v:52:y:2006:i:8:id:4517-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, development and economic importance of Phratora (= Phyllodecta) vitellinae (L.) (Coleoptera, Chrysomelidae) Abstract: The paper summarizes results of the study of the occurrence, development and harmfulness of Phratora (= Phyllodecta) vitellinae (L.). The majority of studies was carried out in 1998 to 2005 in riparian and accompanying stands of the Svitava and Svratka rivers in the region of Brno and in a laboratory. Imagoes leave hibernation hiding places at the end of April and at the beginning of May. In captivity, they lived on Salix fragilis about 2.5 months damaging on average 28.6 cm2 leaf blades and laying on average 293 eggs. In the excessively warm growing season of 2005, imagoes lived about 3.5 months after hibernation, however, already after one month of feeding they fell in a month diapause at the beginning of June. Before its start, they damaged on average 12.8 cm2 (after the diapause 14.4 cm2) leaves and laid on average 389 eggs (of this number, 260 eggs before and 129 after the diapause). Larvae damage about 4 cm2 leaves during 2 to 3 weeks (in the laboratory during 12 to 13 days). After 2 to 3 weeks (in the laboratory after 10 to 12 days) from the cessation of feeding young beetles appear on trees. Imagoes of the 1st generation occur from mid-June to the beginning of October. During about 55 days of life, they damaged 19 cm2 leaves and laid on average 182 eggs. Imagoes of the 2nd generation occur from mid-August to the end of the growing season. After 10 to 14 days of feeding (without previous copulation), they take shelter in wintering places. In the laboratory, however, these imagoes damaged about 19 cm2 leaves during 2 months and laid about 190 eggs. Wintering places were looked up by imagoes of the 3rd generation which damaged on average 4.2 cm2 leaves before hibernation. In the Czech Republic, P. vitellinae is usually bivoltine the 2nd generation being always incomplete. Keywords: Chrysomelidae, Phratora (= Phyllodecta) vitellinae, occurrence, host species, development, generation conditions, harmfulness Journal: Journal of Forest Science Pages: 357-385 Volume: 52 Issue: 8 Year: 2006 DOI: 10.17221/4518-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4518-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-200608-0003.txt Handle: RePEc:caa:jnljfs:v:52:y:2006:i:8:id:4518-JFS