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Results 481 to 510 of 525:

Distribution of sweet chestnut Castanea sativa Mill. in the Czech Republic

P. Haltofová, L. Jankovský

J. For. Sci., 2003, 49(6):259-272 | DOI: 10.17221/4700-JFS

Sweet chestnut Castanea sativa Mill. is an introduced species in the Czech Republic. It is recorded roughly from 300 localities. To the end of 2002, the occurrence of chestnut was verified at about 140 macrolocalities. The most northern locality recorded so far was Choustníkovo Hradiště in the region of Hradec Králové. Chestnuts occur generally to an altitude of 500 m (80% of all examined localities), at higher altitudes they suffer from climatic extremes particularly late frosts. The occurrence of chestnut was recorded at 27 localities (ca. 20% localities under investigation) where altitudes exceed 500 m. The highest location of chestnut is locality Nejdek, Karlovy Vary District where chestnut trees thrive at an altitude of 678 m. At altitudes over 600 m, two other localities were recorded. The health condition of chestnut is relatively good. At some localities, however, crown drying occurs as a result of not quite ideal climatic conditions. Within our research, quarantine Cryphonectria parasitica (Murr.) Barr. was determined for the first time in the Czech Republic at the only examined locality.

Development of the Czech forest related policy and institutions in the threshold of the 3rd millennium

K. Vančura, P. Pacourek, J. Řezáč

J. For. Sci., 2004, 50(11):505-509 | DOI: 10.17221/4647-JFS

This paper gives an overview of Czech forestry policy and legislation since the beginning of changes in the CEEC plus developments and activities of the main forestry institutions. These activities are referred to in the background material given for the political transition period and also related to the Pan-European and global forestry processes. The philosophy of forestry in the Czech Republic is based on the international framework set out by the first Ministerial Conference on the Protection of Forests in Europe and also in conjunction with the preparation of the Czech Republic for accession to the European Union. National and regional forest programmes are aimed at implementing the principles of sustainable forest management and a broad range of stakeholders from the forestry and environment sectors has been involved in its preparation. The current situation and main problems of forestry are given along with basic principles on how to solve such problems and also on how to fulfil obligations to future generations, and international commitments.

Changes in trends of the height growth of spruce and pine derived from continuous measurements in forest management plans of Kostelec nad Černými lesy and on pilot research plots in the Czech Republic

J. Sequens, M. Křepela, D. Zahradník

J. For. Sci., 2004, 50(7):327-337 | DOI: 10.17221/4630-JFS

In changing growth conditions, methodical procedures should concentrate on the investigation of processes currently under way in forests. Many studies have shown that present models of forest growth parameters differ from previous surveys as far as for instance the height is concerned. Causes of these phenomena have not been satisfactorily explained although various hypotheses are investigated. In our study, we present partial results of the investigation of height growth within a sixty-five-year period, based on the analysis of data obtained from seven forest management plans in the management-plan area of Kostelec nad Černými lesy (Kostelec n. Č. l.) and continuous measurements on pilot research plots in the period of 1965-1994. The comparison of mean height growth curves obtained by the curve fitting of the values of empirical data signifies by their different course and increasing kurtosis a dependence on the calendar year when the measure was taken. It signifies an increasing height growth trend of both species in the given area.

Biology and harmfulness of Eriosoma (= Schizoneura) ulmi (L.) (Aphidinea, Pemphigidae) in elm

J. Urban

J. For. Sci., 2003, 49(8):359-379 | DOI: 10.17221/4710-JFS

The paper deals with the occurrence, development, natural enemies and harmfulness of a heteroecious aphid Eriosoma (= Schizoneura) ulmi (L.) which showed outbreaks in elm Ulmus glabra Huds. in Moravia in 2002. At main localities under study in Bílovice nad Svitavou and Brno-Jundrov, the aphid damaged about 63% leaves. Larvae of fundatrices hatched from mid-April and their development from hatching to maturity took about 14 days. Mature fundatrices occurred in May and reproduced for a period of 14 days. Their average physiological fecundity amounted to 311 larvae and ecological fecundity 291 larvae. Migrantes alatae occurred in galls from 18 May to 15 June and their physiological fecundity was about 22 larvae. Leaves were damaged even by 3 galls of an average length of 41 and width 11 mm. Sucking affected on average 11 cm2, i.e. 27% (in case of the occurrence of 2 or 3 even 100%) leaf area. Natural enemies killed 90% aphids. A bug Anthocoris confusus Reut. killing aphids in 80% galls was the most effective control agent. Its eggs occurred from 25 April to 25 May and nymphs from 3 May to 25 June. Larvae of Syrphidae [mainly Syrphus ribesii (L.)] killed the aphids in 4 and birds in 6% galls. E. ulmi should be considered to be an important occasional pest of orchards and forests.

Real potentials of social forest functions of selected forest stands at Židlochovice Forest Enterprise

P. Kupec

J. For. Sci., 2004, 50(4):190-198 | DOI: 10.17221/4614-JFS

Social functions of forests were evaluated at Židlochovice Forest Enterprise by applying the method of Vyskot et al. (1996-2002). Real potentials of social forest functions were determined for all stand groups included in a forest management plan (FMP). The results of evaluation were processed in a database and projected in GIS. Tables and charts were used for the evaluation of results. We can claim on the basis of the results that the forest stands of the examined area are characterized by a very high potential to fulfil a bio-production social function. On the contrary, they have a low potential to fulfil social functions of ecological stabilization and edaphic soil conservation and hydric-hydrological function. The results of evaluation of the real potentials of social forest functions at Židlochovice Forest Enterprise are represented by the forest stands of management group No. 19 of forest management plan area Židlochovice.

Notes to distribution and seasonal activity of spruce diprionids (Hymenoptera: Diprionidae) in the eastern part of the Czech Republic

J. Holuša, L. Roller

J. For. Sci., 2004, 50(12):579-585 | DOI: 10.17221/4660-JFS

A study of diprionids associated with spruce was done at 31 sites of the eastern part of the Czech Republic in 1988-2003. In total 45 specimens belonging to Gilpinia abieticola (6 specimens), G. hercyniae (3) and G. polytoma (36) were collected using Malaise traps, emergency traps, bark-beetle pheromone baited traps or sweeping. The spruce diprionids were recorded in 30% of the studied sites only. G. polytoma was the most abundant and it is probably bivoltine with adult activity from April to August. The results of emergence trap-monitoring in Paskovský les indicate that this species is in latency.

Analysis of forestry financing in the Czech Republic in the period of transition to market economy

L. Šišák, M. Chytrý

J. For. Sci., 2004, 50(2):78-85 | DOI: 10.17221/4603-JFS

The article is devoted to problems of forestry financing in the Czech Republic in the period of transition to market economy (1991-1999). The policy of forestry financing is aimed above all at the provision and improvement of quality of sustainable non-market forest goods and services. Thirty programmes and 46 sub-programmes were analysed in the CR in 1991-1999. The level of financial support ranged from 909.4 mil. CZK to 1,501.7 CZK with the exception of 2,540.1 mil. CZK in 1991 (all in stable 1999 prices). On average, the support amounted to about 10% of the GDP created by the forestry sector in the given period.

Development of forest stands condition and its monitoring in the Czech Republic

P. Fabiánek, V. Henžlík, K. Vančura

J. For. Sci., 2004, 50(11):514-519 | DOI: 10.17221/4649-JFS

In 1986, the UN ECE established the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (hereinafter ICP Forests) to respond on the growing concern about forest damage caused since the beginning of eighties by air pollution load. Pan-European grid of the (ICP Forests) monitoring plots represents one of the most important systems of forest ecosystems assessing and checking. The Czech Republic is unfortunately well known due to this problem and so the country joined ICP Forest Programme since the very beginning. The paper presents general information on Czech forest stand condition that gained through various methods in the past as well as in the frame of ICP Forests. The participation in the International Cooperative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) represents a contribution of the EU candidate country to the fulfillment of the Reg. (EEC) No. 3528/86. However it seems that effects and importance of air pollution are decreasing, a lot of new stress situations exists and there is a need for continuing the programme.

Influence of forest stand structure on the occurrence of bird community in Skalná Alpa National Nature Reserve in the Veľká Fatra Mts. (West Carpathians)

M. Saniga, M. Saniga

J. For. Sci., 2004, 50(5):219-234 | DOI: 10.17221/4618-JFS

The study deals with the influence of the structure, texture and dynamics of a spruce-beech primeval forest on the bird community in Skalná Alpa National Nature Reserve in the Veľká Fatra Mts. (West Carpathians, Slovakia) in the years 1982-2002. The abundance of Norway spruce (Picea excelsa Lam.) was highest both in the optimum and decomposition stage. In the growth stage the number of Norway spruce (Picea excelsa Lam.) trees was quite low. The texture of spruce-beech virgin forest was very variable. Percentage ratios of individual stages on the area of 42.16 ha were as follows: growth stage 38.3%, optimum stage 20.1% and decomposition stage 41.6%. Altogether 46 bird species were represented in the bird community during the spring season. Mean total density was 85.8 ind/10 ha. The bird community consisted of 52 species in the summer season, 45 in the autumn migration season, 34 in the winter season, and of 47 in the spring migration season. The highest density was found in the bird community during the autumn migration season (109.8 ind/10 ha), the lowest in the winter season (24.6 ind/10 ha). During the spring migration season, both the spectrum of bird species and total density of bird community increased by the number of migratory species that came back from winter habitats.

Structure and accumulation of litterfall under Norway spruce stands in connection with thinnings

J. Novák, M. Slodičák

J. For. Sci., 2004, 50(3):101-108 | DOI: 10.17221/4605-JFS

The effect of thinning on the structure and accumulation of litterfall and holorganic horizons (L, F, H) in young Norway spruce stands was investigated. The research was conducted on a Norway spruce thinning experiment Polom (established in 1980) in the Orlické hory Mts. (north-eastern part of the Czech Republic). In 1992, the monitoring of litterfall started on an unthinned control stand (plot 1) and on a comparative stand with very heavy thinning from below (plot 3). During the period of observation (age of the stand 27-37 years), the total weight of litterfall ranged between 1,800 and 4,800 kg/ha. The amount of litterfall was partly influenced by climatic factors (precipitation and temperature), growth processes (basal area increment) and thinning regimes in individual years. The results of the investigations showed that dry biomass accumulated under a 36 years old Norway spruce stand ranged from 9,200 to 11,300 kg/ha in horizon L, from 37,000 to 38,200 kg/ha in horizon F and from 138,300 to 146,400 kg/ha in horizon H. The quality (content of basic nutrients) of litterfall and material from holorganic horizons are discussed.

A new concept in sustainable forest management - the need for forest ecosystem and landscape research

J. Kulhavý

J. For. Sci., 2004, 50(11):520-525 | DOI: 10.17221/4650-JFS

The greatest advance in ecosystem research was made in the last century. The development and acceptance of forest ecology by foresters occurred because it provided a means for recognizing, understanding, classifying and mapping the natural variation of forests. Forest ecology involved studies at the individual, population, community, and ecosystem levels but such studies always needed to involve the ecosystem concept. Today, the new concept of "ecosystem and landscape forestry" integrating ecological and socio-economic research has been developed on the basis of EU COST Action E-25 European Network for a Long-term Forest Ecosystem and Landscape Research Programme. An analysis has been carried out of the present situation in forest research in the Czech Republic. The need for forest ecosystem and landscape research is obvious.

Induced wound response of Norway spruce Picea abies P. Karst. after artificial inoculation by imagoes of Ips typographus

L. Jankovský, D. Novotný, R. Mrkva

J. For. Sci., 2003, 49(9):403-411 | DOI: 10.17221/4713-JFS

Inoculation experiments were carried out on a set of trees with imagoes of Ips typographus L. which origin from the Šumava Mts. and the Křtiny Training Enterprise. The objective of back inoculations was to determine whether species found on the surface of Ips typographus imagoes spread after the inoculation also through host tissues. It the vicinity of inoculation by Ips typographus imagoes, marked necrotic zones are evident including symptoms of the penetration of vascular pathogens through phloem and sapwood. The most marked reactions were observed in case of inoculation by an untreated Ips typographus imago. Treatment of Ips typographus imagoes by Ibefungin and Fundazol preparations did not demonstrate expected effects in full scale. The spores of several ophiostomoid fungi like Ceratocystis polonica (Siem.) C. Moreau were observed on the surface of bark beetles and at the same time were re-isolated from wounds inoculated by Ips typographus imagoes. The other fungi like Ophiostoma bicolor Davidson & Wells, Leptographium cf. lundbergii Lagerberg & Melin., Pezicula eucrita Karst., Phomopsis sp. and other were found in wounds with the imagoes artificial infection.

Soil conditions of black walnut (Juglans nigra L.) stands in the alluvium of the Svratka and Jihlava riversOriginal Paper

M. Hřib, J. Kulhavý, M. Sáňka, J. Lesná

J. For. Sci., 2002, 48(11):486-498 | DOI: 10.17221/11917-JFS

Physical, chemical and microbiological properties of soils were studied in black walnut (Juglans nigra L.) stands and compared with those in stands of natural species composition, in mixed stands of black walnut with linden and in pure oak stands. The objectives were to consider a possibility of black walnut planting at floodplain sites in the alluvial area of Southern Moravia. The first results did not show any worsening of soil properties and soil production potential. A positive amelioration effect of soil- improving species was proved in black walnut stands.

Application of logistics in woodworking industry

J. Štůsek

J. For. Sci., 2004, 50(3):142-148 | DOI: 10.17221/4609-JFS

The paper is focused on logistics. The importance of the logistic chain management is emphasized as it becomes a crucial competitive success factor. The total corporate costs and customer service quality are dependent on the structure and communication within this chain. Using a concrete example, several results of the establishment of the logistic approach in the woodworking industry are mentioned in the paper. It has to be emphasized that the application of the logistic principles in the industry has its own specificities arising mainly from the biological character of processes providing and manufacturing the basis resource. A solution of the supply - purchase chain is provided on the basis of an example of the company Dřevovýroba.

Prosperity of spruce plantation after application of dolomitic limestone powder

I. Kuneš

J. For. Sci., 2003, 49(5):220-228 | DOI: 10.17221/4696-JFS

The subject of this paper was to assess the effects of pulverised dolomitic limestone applications on prosperity of Norway spruce (Picea abies L.) plantation and on the soil in extreme ecological conditions of the Jizerské hory Mts. The characteristics such as plant mortality, annual height increment, diameter of root collar (stem base diameter), crown diameter, nutrient analyses and some data from soil analyses are evaluated in this paper. An eleven-year period of observations is summarised. According to the observations and measurements carried out until now, the effect of limestone applications (1 kg per tree) on the spruce plantation prosperity seems to be positive without any serious negative impacts on the soil.

Effect of fertilisation on Norway spruce needles

V.V. Podrázský, S. Vacek, I. Ulbrichová

J. For. Sci., 2003, 49(7):321-326 | DOI: 10.17221/4706-JFS

Yellowing of Norway spruce is a relatively common problem in many regions of the Czech Republic. At some places, it is also connected with forest decline. This unfavourable phenomenon is initiated by several ecological as well as anthropogenic processes. One of the most important is the imbalance of forest stand nutrition. Particular reasons lead to nutrient deficiency, especially deficiency of magnesium. Solution to this undesirable trend is a profound ecological analysis and cause-oriented treatments. Besides decreasing air pollution impacts, fertilisation with deficient nutrients represents a successful treatment in the forest stand management in affected areas. In the area of interest, application of relatively small amounts of appropriate fertiliser (SILVAMIX Mg) led to considerable improvement in the defoliation dynamics and yellowing progress since the first year after application.

Discrimination of vegetation from the background in high resolution colour remote sensed imagery

P. Surový, N.A. Ribeiro, A.C. Oliveira, Ľ. Scheer

J. For. Sci., 2004, 50(4):161-170 | DOI: 10.17221/4611-JFS

Different transformations of RGB colour space were compared to develop the best method for discrimination of vegetation from the background in open pure cork oak stands in southern Portugal in high-resolution colour imagery. Normalised difference index, i1i2i3 colour space and other indices developed for classic band imagery were recalculated for near infrared imagery and tested. A new method for fully automated thresholding was developed and tested. The newly developed index shows the equal accuracy performance but provides the smallest overestimation error and retains the largest scale of grey levels for a subsequent shape analysis.

Forestry, mountain catchments and floods in the Czech Republic

M. Bíba, J. Jiřík, K. Vančura

J. For. Sci., 2004, 50(11):538-541 | DOI: 10.17221/4653-JFS

A short introduction of historical overview and current situation refer to forestry problems of the country. Local climate is characterized and impacts of natural phenomena are described, as well as the impacts of human beings. The influence of forest management is mentioned and discussed in relation to latest catastrophic floods. The territory of the Czech Republic is damaged especially by a high intensity of atmospheric precipitation abnormal values which lead to a local or regional damage. In the catchment areas of torrents, damage leads to faster soil erosion, development of ravines, landslides, moving of soil sediments and their deposition, devastation of watercourse beds and properties, flooding while the flooding rates of flow represent a danger for the life of inhabitants. Important elements and results of respective research are described in brief. E.g. research of precipitation and its relation to the runoffs in the small mountain catchment areas with the forest stands restoration, as well as the forestry-hydrologic monitoring of forest environment, which has been taking place since 1928, and tradition of the service for torrent control. Forestry-hydrologic research gradually documents that a favorable flood-control performance of forest is limited. However, this is not a reason for not taking care of flood-control measures in the mountain afforested areas. These measures and importance of forest for the protection of land are historically verified and justified. In closing the mankind behavior to the landscape is underlined as a question mark.

Effects of pruning on heartwood formation in Scots pine trees

B. Bergström, R. Gref, A. Ericsson

J. For. Sci., 2004, 50(1):11-16 | DOI: 10.17221/4595-JFS

The object of this study was to investigate the effect of pruning on heartwood formation in mature Scots pine (Pinus sylvestris L.) trees. Fifty trees were treated by three different intensive pruning regimes: 42, 60 and 70 percentage of defoliation. After five growing seasons numbers of growth rings were counted and the width and the area of sapwood and heartwood were calculated. The results did not show any proportional increase or decrease in the heartwood area or in the number of growth rings in heartwood associated with the pruning. A statistically significant negative effect of pruning was found on the width of the five most recently formed sapwood growth rings. This decreased growth rate did not influence the ratio of sapwood and heartwood. However, it cannot be excluded that the proportion of heartwood may increase during a longer period. It is concluded that pruning is not a practicable silvicultural method for regulating heartwood formation in mature Scots pine trees.

The ground beetles (Coleoptera: Carabidae) of forest altitudinal zones of the eastern part of the Krušné hory Mts.

E. Kula, L. Purchart

J. For. Sci., 2004, 50(10):456-463 | DOI: 10.17221/4641-JFS

By means of Sörensen's index and Renkonen's number, the differences in species composition and abundance of the ground beetles (Carabidae) were specified in 5 forest altitudinal zones (3rd, 5th-8th) and also the faunal similarity in the linking-up forest altitudinal zones. The entry of some species (Carabus coriaceus, Carabus violaceus, Pterostichus niger and Pterostichus oblongopunctatus) into higher altitudes was much more marked than is mentioned in hitherto published information. The objective of the present study was to explore the potential use of the ground beetles as an ancillary component of the geobiocoenological typological system.

Optimisation of forest road network under principles of functionally integrated forest management

P. Hrůza

J. For. Sci., 2003, 49(9):439-443 | DOI: 10.17221/4717-JFS

A traditional approach to problems of the opening-up of forests has been based primarily on technical and economic aspects. It results particularly from the ground configuration and calculations of minimum costs for logging and transport operations. Optimum density of main forest roads is determined by a minimum value of the summary curve of costs of forest road construction and timber skidding. A new conception from the aspect of integrated forest management taking into account forest functions is based on a standard approach when technical and economic aspects are complemented by the particular functions of the forest. Thus, the technical and economic approach is changed to a technical-economic-environmental conception that will contribute to a reduction in negative effects of the construction of forest road network on the environment.

Relation of dead wood course within the development cycle of selected virgin forests in SlovakiaOriginal Paper

M. Saniga, J.P. Schütz

J. For. Sci., 2002, 48(12):513-528 | DOI: 10.17221/11920-JFS

Following measurements of dead wood (20 to 40 years) at various developmental stages of the life cycle of selected virgin forests of the 1st to 7th altitudinal zone the relation of its course was derived. The dynamics and course of dead wood in the life cycle of virgin forests were best represented by a polynomial of the third degree. An analysis confirmed that virgin forests consisting of stable tree species with approximately the same physical age (Boky) showed small differences between maximal increase and decrease in necromass during the whole development cycle. Virgin forests at sites rich in nutrients consisting of several tree species with various physical age had high values of necromass during their whole development cycle. Spruce stands at the upper forest boundary also had a relatively high ratio of necromass at the advanced optimum stage.

Mountain Norway spruce forests: Needle supply and its nutrient content

M. Kovářová, S. Vacek

J. For. Sci., 2003, 49(7):327-332 | DOI: 10.17221/4707-JFS

Soon after bark-beetle attack as well as after clear cutting, grown-up mountain Norway spruce forest cast the following mass of needles: 50-60 kg of dry matter per tree, or 18-20 tons per hectare, containing 8,800-10,000 kg/ha of carbon, 190 to 250 kg/ha of nitrogen, 13-16 kg/ha of phosphorus, 65-91 kg/ha of calcium, 9-13 kg/ha of magnesium and 56-67 kg/ha of potassium. These values were obtained by application of equations assessing needle mass from measured tree and plot parameters, and from chemical analyses of two types of needle material (from living and dead trees).

A contribution to the effect of liming on forest soils: review of literature

P. Formánek, V. Vranová

J. For. Sci., 2003, 49(4):182-190 | DOI: 10.17221/4692-JFS

Extensive forest areas were ameliorated by large-scale liming in the last years in order to prevent proceeding acidification and degradation of forest soils. The hitherto knowledge of liming effects on the function of forest soils still appears insufficient for an unambiguous evaluation. Sorption properties of soils and acidity are favourably affected by liming and the favourable effect is usually manifested in the layer of forest floor humus and in mineral soil within ten years. Reduction of soil acidity stimulates development of a bacterial component of microflora, soil edaphon, and good prerequisites are formed for a release of nutrients from soil organic matter. Improvement of some physical parameters of soils and negative effect of liming on the depth of rooting in spruce, availability of nutrients at some sites and in connection with mechanical soil preparation were also described. A key point of liming effect on forest soils is nitrogen dynamics. Mineralization of nitrogen is stimulated at nitrogen-rich sites with C/N < 30. Nitrogen-limited sites show nitrogen mineralization inhibited by liming with signs of pronounced deficiency in spruce nutrition. A positive effect of liming on nutrition with bases is generally accompanied by an adverse influence on N dynamics in acidic soils under spruce monocultures. Therefore it is possible to state that liming induces relatively marked changes in the soil but the actual growth response of woody species cannot be derived only from these changes.

Quantitative and qualitative damage caused by mammals and birds to the planting and natural seeding

M. Saniga

J. For. Sci., 2003, 49(1):37-43 | DOI: 10.17221/4676-JFS

In the years 1999-2000, I studied damage to transplants in the planting and wildlings in the natural seeding at the locality Zamrlô in the Starohorské vrchy Mts. (750-1,000 m a.s.l., NE exposure, forest type Abieto-Fagetum). Damage to the woody plants by the mammals and birds in the planting was much higher (14%) than in the natural seeding (7%). All woody plant species were also more damaged in the planting (spruce 16%, larch 9%, fir 24%, beech 10%, and sycamore 10%) than in the natural seeding (spruce 7%, larch 6%, fir 10%, beech 7%, and sycamore 9%). There were found 8 mammals that damaged woody plants both in the planting and natural seeding (Apodemus sp., Capreolus capreolus L., Cervus elaphus L., Clethrionomys glareolus SCHREB., Lepus europaeus L., Microtus agrestis L., Microtus arvalis PALL., Sciurus vulgaris L.). Only one bird species was found to damage woody plants in the planting and natural seeding (Tetrao urogallus L.).

Assessing the occurrence of Vitis vinifera subsp. sylvestris (C. C. Gmelin) Hegi in the Czech RepublicOriginal Paper

P. Maděra, M. Martínková

J. For. Sci., 2002, 48(11):482-485 | DOI: 10.17221/11916-JFS

The objective of the paper is taxonomic evaluation of a woodland grape individual found near the Dyje river. The finders (Vicherek et al. 2000) determined the liana as Vitis vinifera subsp. sylvestris. Based on microscopic observations of bud sections some doubts were cast on the classification to the subspecies of sylvestris. Correct determination will be possible only on the basis of further observations of the found individual and its comparison with real members of the taxon (Čenkov, SR).

Hymenoptera (Aculeata) of spruce stands in the air-pollution region of Northern Bohemia

E. Kula, P. Tyrner

J. For. Sci., 2003, 49(5):200-207 | DOI: 10.17221/4694-JFS

Using Moericke's yellow dishes we studied the Hymenoptera (Aculeata) fauna (with the exception of Formicoidea) in spruce (Picea abies) stands of the colder region of Northern Bohemia. We collected 103 species and the most important species in this spectrum were Vespula vulgaris (56.4%), Vespula rufa (4.7%), Dolichovespula norvegica (3.1%), Dolichovespula saxonica (4%), Nysson spinosus (1.8%), Andrena lappona (1.9%), Cleptes semiauratus (5.9%), Halictus sp. (6.7%) and Trypoxylon minus (2.2%). Comparisons made in 1990-1994 and 1995-1999 indicated a recession of species of the genus Halictus, of Andrena nitida (Apidae), Pemphredon lugubris, Trypoxylon clavicerum and T. minus (Sphecidae), and an increased abundance of Cleptes semiauratus (Cleptidae), Nysson spinosus (Sphecidae), Vespula vulgaris and V. rufa (Vespidae). Compared to closed stands, open spruce stands had a greater species diversity and lower number of captured specimens.

Monitoring of sawfl y ( Hymenoptera: Tenthredinidae Hymenoptera: Tenthredinidae ) infestation on spruceOriginal Paper

J. Holuša, O. Holuša

J. For. Sci., 2002, 48(5):219-224 | DOI: 10.17221/11877-JFS

A new method for evaluating damage caused by tenthredinids to Norway spruce stands is based on defoliation of the top whorls. A scale with four classes of defoliation was established that is easy to use. Defoliation can be displayed graphically on a grid map (Central European system), in which the map fi elds are delimited by parallels of latitude (6 by 6 minutes) and meridians (10 by 10 minutes) with an approximate size of 11.2 × 12.0 km. The degree of defoliation for an entire forest can be marked by circles of different size in the map field. The range and intensity of an infestation, and the change in defoliation from year to year are easily seen.

Introskeletal erosion threat in mountain forests of the Czech Republic

S. Vacek, V.V. Podrázský, M. Mikeska, W.K. Moser

J. For. Sci., 2003, 49(7):313-320 | DOI: 10.17221/4705-JFS

Summarization of the potential of introskeletal erosion (ISE) was done on the basis of field surveys in the Šumava Mts., Krkonoše Mts. and Jeseníky Mts. areas. The results give a rough estimation of the ISE extent in mountain forests of the Czech Republic. They indicate that in the mountainous areas of the Czech Republic there are 46,535 ha of forest lands endangered by these processes, which represents 10.1% of mountain forests and 1.7% of the total forest area in the country. The worst situation is in the Krkonoše Mts., where the considerable ISE potential is on 30.5% of forest area (in the Jeseníky Mts. 16.6%, in the Novohradské hory Mts. 13.3%, in the Šumava Mts. 8.2%). Because these areas are relevant production and water protection areas, the ISE processes have to be studied carefully and forest lands have to be protected, also using special technologies for forest protection and restoration.

Occurrence, development and natural enemies of Pemphigus spyrothecae (Homoptera, Pemphigidae)Original Paper

J. Urban

J. For. Sci., 2002, 48(6):248-270 | DOI: 10.17221/11883-JFS

In 2001, galls were analysed of Pemphigus spyrothecae Pass. taken in one- to three-week intervals from Populus nigra and P. nigra var. italica at 4 localities in Brno. Fundatrices matured in the first half of June and during the first half of summer produced about 50 offsprings. Virgines produced about 10 offsprings which grew up in winged sexuparae. The winged individuals started to occur in galls from the beginning of August. In galls with intact development, on average 500 aphids developed. Galls with intact development on P. nigra var. italica reached larger average dimensions and contained at least by 4% more aphids than galls on P. nigra. About 5% of fundatrices died already in the 1st instar and other 3 to 6% in higher instars by the beginning of reproduction. At localities under investigation, 7.5 to 39.0% of galls on P. nigra and 3.9 to 13.7% of galls on P. nigra var. italica were occupied by the fly Leucopis puncticornis Meig. (Chamaemyiidae). About 24.3 to 32.2% of galls on P. nigra and 23.3 to 49.3% of galls on P. nigra var. italica were occupied by the bug Anthocoris minki Dohrn (Anthocoridae). Hover flies Heringia heringi (Zett.) and Pipiza festiva Meig. (Syrphidae) killing aphids in 3.8 to 30.4% of galls on P. nigra and 6.5 to 6.8% of galls on P. nigra var. italica were an important regulator. In August (i.e. at the beginning of the formation of winged sexuparae), the majority of galls opened through primary slit-shaped or oval emergence holes. A part (7.8 to 19.5%) of galls with so far intact development, however, remained closed and all aphids contained in them died. Diseases (particularly mycoses) often participated in the accelerated dying of aphids. The effect of mortality factors on the gall size differentiation was evaluated in details. The galls do not cause any leaf area reduction. In the case of mass outbreak, they decrease decorativeness of poplars in street alleys. In August and September, liquid excrements fall out from the galls (honeydew) polluting the environment in villages and housing estates.

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