Template-Type: ReDIF-Article 1.0 Author-Name: Ľ. Scheer Author-Workplace-Name: Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovak Republic Author-Name: R. Sitko Author-Workplace-Name: Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovak Republic Title: Assessment of some forest characteristics employing IKONOS satellite data Abstract: In recent years, satellite remote sensing has become a new tool for estimation of forest condition. The paper deals with spruce timber growing stock and vegetation cover assessment employing IKONOS satellite data from a mountain forest area of Central Slovakia. Original digital data as well as enhanced digital images were used to estimate some forest variables. Image enhancement approaches employing topographic normalization, PCA analysis and different vegetation indices are a very important part of data processing. Apart from spectral characteristics, texture as an additional variable was utilized. In order to improve classification accuracy the knowledge of the vertical distribution of tree species also was incorporated into classifiers. Spectral signatures as auxiliary variables measured with the aid of training sets were utilized for the construction of spectral models for growing stock estimation. In spite of the fact that the standard error of these models is not very favourable as it varies about 30%, they offer initial information for application of different sampling designs for timber growing stock assessment, where the final precision is acceptable. Stepwise discriminant analysis was employed to choose appropriate sets for the classification of vegetation cover. Classification results show an assumed contribution of categorial knowledge for increasing the correctly classified pixel proportion and this improvement was on average about 10%. Likewise, the texture contributes to better resolution of some very near spectral classes. Keywords: IKONOS, timber growing stock, texture, categorial knowledge, vegetation cover Journal: Journal of Forest Science Pages: 345-351 Volume: 53 Issue: 8 Year: 2007 DOI: 10.17221/2181-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/2181-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-200708-0001.txt Handle: RePEc:caa:jnljfs:v:53:y:2007:i:8:id:2181-JFS Template-Type: ReDIF-Article 1.0 Author-Name: M. Moravčík Author-Workplace-Name: National Forest Centre - Forest Research Institute, Zvolen, Slovak Republic Title: Derivation of target stocking for forests of Norway spruce vegetation zone in Slovakia Abstract: The present paper deals with derivation of target stocking in forests of Norway spruce vegetation zone. Target stocking in forests with prevailing ecological and social functions is the stocking when the forest fulfils demanded functions in the best way. For forests in the Norway spruce vegetation zone target stocking was derived by original procedures as an optimum stocking in harmonization of demands on the fulfilment of ecological functions (especially erosion control, hydrological and water protection ones), securing static stability and preconditions for the formation and growth of natural regeneration. We investigated the relations between stocking and indicators of static stability (slenderness coefficient and ratio of crown length to tree height), natural regeneration phases, ground and non-wood vegetation coverage and natural regeneration coverage. The most favourable status of these indicators was found out in stocking 0.7 and in the upper forest limit 0.6. Keywords: Norway spruce vegetation zone, target stocking, static stability, slenderness coefficient Journal: Journal of Forest Science Pages: 352-358 Volume: 53 Issue: 8 Year: 2007 DOI: 10.17221/2183-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/2183-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-200708-0002.txt Handle: RePEc:caa:jnljfs:v:53:y:2007:i:8:id:2183-JFS Template-Type: ReDIF-Article 1.0 Author-Name: V. Malík Author-Workplace-Name: School Forest Enterprise at Kostelec nad Černými lesy, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: J. Stuchlý Author-Workplace-Name: School Forest Enterprise at Kostelec nad Černými lesy, Czech University of Life Sciences Prague, Prague, Czech Republic Title: Risk factors influencing the probability of browsing by hoofed game on forest trees Abstract: In this paper we analyze how selected risk factors determine the probability of browsing by hoofed game on forest trees. Risk factors covered by the model are: tree species (Norway spruce or Scotch pine), time period (season: spring + summer or autumn + winter) and chemical structure of bark (content of selected nutrients and chemical elements). We use a logit model for these purposes. We formulate the model and perform linear transformation by the natural log. Since the disturbance term in the logit model is heteroscedastic, we cannot use the ordinary least-squares method to estimate the parameters of the model. In this case the maximum likelihood method included in STATGRAPHICS Plus for Windows program is used for its estimation. We use a random sample of data including 59 trees. We do the interpretations of the estimated parameters and other characteristics. We demonstrate how the estimated probabilities depend on the considered factor. The model explains 44.1% of variations of the logits, the model is statistically significant. All regression coefficients are significant at least at 12% confidence level. Among the main explanatory variables (content of P, Ca, NO3, tree species and season), the P and Ca contents in the bark of the tree are the most important factors influencing the probability of future damage to the tree. Keywords: element contents, bark, spruce, pine, logit model, odds ratios Journal: Journal of Forest Science Pages: 359-363 Volume: 53 Issue: 8 Year: 2007 DOI: 10.17221/2179-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/2179-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-200708-0003.txt Handle: RePEc:caa:jnljfs:v:53:y:2007:i:8:id:2179-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, biology and harmfulness of Galerucella lineola (F.) (Coleoptera, Chrysomelidae) - Part 1. Last year's (parent) beetles Abstract: In Moravia in 1995 to 2006, the abundant occurrence of Galerucella lineola (F.) was used to study its occurrence, biology and harmfulness. An "alder" biological form was studied in Alnus glutinosa and A. incana mainly in Polnička Forest District (Žďár region) and a "willow" form in Salix viminalis, S. triandra and S. caprea in riparian and accompanying stands of the Svitava river near Bílovice nad Svitavou (Brno region). Imagoes leave their sites usually in the 1st half of May. In the course of 2.5 to 3 months, they damage on average 22.6 cm2 leaves of A. glutinosa and S. caprea (of this value, males 3.2 times less than females). Males eat on average 15 times during 24 hours for a period of 3.5 minutes, i.e. in total 52 minutes (3.6% day). Females eat on average 36 times for a period of 7 min, i.e. 252 min (17.5% day). Imagoes copulate on average 10.2 times per day for a period of 67 min. For the whole period of reproduction (about 42 days), they copulate on average 428 times, i.e. for 20 days. Eggs are laid into groups of 3 to 20 (on average 14) pieces. Females lay 457 to 791 (on average 612) eggs, i.e. about 15 eggs per day. Medina collaris (Fall.) (Tachinidae) and Townesilitus fulviceps (Ruthe) (Braconidae) belong, among others, to the enemies of imagoes. Keywords: Chrysomelidae, Galerucella lineola, host species, hibernation, feeding, last year's imagoes, reproduction, natural enemies Journal: Journal of Forest Science Pages: 364-380 Volume: 53 Issue: 8 Year: 2007 DOI: 10.17221/2182-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/2182-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-200708-0004.txt Handle: RePEc:caa:jnljfs:v:53:y:2007:i:8:id:2182-JFS Template-Type: ReDIF-Article 1.0 Author-Name: V. Skuhravý Author-Workplace-Name: Prague, Czech Republic Author-Name: C. Thuróczy Author-Workplace-Name: Koszeg, Hungary Title: Parasitic Hymenoptera associated with Thecodiplosis brachyntera (Diptera: Cecidomyiidae) on the genus Pinus (Pinaceae) in the Czech Republic Abstract: Aprostocetus micantulus (Thomson, 1878) (Chalcidoidea: Eulophidae), Torymus heyeri Wachtl, 1833 (Chalcidoidea: Torymidae), Pseudencyrtus idmon (Walker, 1848) (Chalcidoidea: Encyrtidae) and Platy-gaster compressicornis (Thomson, 1859) (Platygasteroidea: Platygasteridae) are four main parasitoids reared from galls of Thecodiplosis brachyntera (Schwägrichen, 1835) (Diptera: Cecidomyiidae) developing on Pinus mugo L., P. rotundata Link, P. sylvestris L. and P. × pseudopumilio (Willk.) G. Beck (Pinaceae) in the Czech Republic during outbreak 1967-1972. Of total 4,279 parasitoid specimens, Platygaster compressicornis (1,778 specimens, 41%) was the most abundant, Aprostocetus micantulus (1,047 specimens, 25%) and Pseudencyrtus idmon (1,020 specimens, 24%) less abundant and Torymus heyeri (434 specimens, 10%) was on the fourth place of abundance. In laboratory conditions, adults of Platygaster compressicornis emerged simultaneously with adults of T. brachyntera, adults of Pseudencyrtus idmon and Torymus heyeri 14-24 days after emergence of T. brachyntera and adults of Aprostocetus micantulus after 24-60 days. Behaviour of adult parasitoid during the process of building the opening hole to escape from gall is described. Larvae identified and figured by FANKHÄNEL and ZELETZKI (1964) as larval stage of Misocyclops pini are misidentification; in reality they are the salivary glands of larvae of Thecodiplosis brachyntera. Keywords: Hymenoptera, parasitoids, Chalcidoidea, Eulophidae, Torymidae, Encyrtidae, Platygasteroidea, Diptera, Cecidomyiidae, Thecodiplosis brachyntera Journal: Journal of Forest Science Pages: 381-389 Volume: 53 Issue: 8 Year: 2007 DOI: 10.17221/2180-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/2180-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-200708-0005.txt Handle: RePEc:caa:jnljfs:v:53:y:2007:i:8:id:2180-JFS