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Results 661 to 690 of 740:

Dead wood and mycoflora in Nature Reserve Polom, Protected Landscape Area Železné hory

L. Jankovský, J. Beránek, A. Vágner

J. For. Sci., 2004, 50(3):118-134 | DOI: 10.17221/4607-JFS

Activity of fungi participating in the dead wood decomposition was studied in the Velký Polom Nature Reserve, Protected Landscape Area Železné hory. Two game-proof fences of an area of 0.30 ha (570 m alt.) and 0.19 ha (620 m alt.) were used as permanent sample plots. In both the plots, activities were monitored of wood-destroying fungi in 126.82 m3 dead wood, 104.05 m3 of which were in beech. After conversion to an area, the volume amounts to 258.82 m3 per ha. In the whole reserve, almost 220 species of macromycetes were recorded in the course of a mycological survey. Wood-destroying fungi are the dominant component of mycoflora representing more than 50% identified taxa of in the period under study. The proportion of mycorrhizal fungi amounted to 14%. A series of macromycetes considered to be saprophytes is bound to products of wood decomposition. Fomes fomentarius (L.) Fr., Fomitopsis pinicola (Sowerby) P. Karst., Ustulina deusta (Fr.) Petrak, Hypoxylon fragiforme (Pers.) Kickx, Ganoderma lipsiense (Batsch) Atk. and the genus Armillaria were the predominant species of wood-decaying fungi. As for rare macro-fungi, it is possible to mention Ascotremella faginea (Peck) Seaver, Stropharia albocrenulata (Peck) Kreisel and Tricholomopsis decora (Fr.) Singer.

Influence of amphibolite powder and Silvamix fertiliser on Norway spruce plantation in conditions of air polluted mountains

I. Kuneš, V. Balcar, M. Čížek

J. For. Sci., 2004, 50(8):366-373 | DOI: 10.17221/4663-JFS

The objective of the paper is to assess the effects of amphibolite powder (waste from a dust removing process in a rock pulveriser) and Silvamix slow release fertiliser on Norway spruce plantation in the harsh physical environment of the Jizerské hory Mts. The plantation characteristics such as mortality, annual height increment, stem base diameter, crown diameter and nutrient analyses are evaluated. A nine-year-long period of observation is summarised. The effects of both the forms of chemical amelioration seem to be positive and statistically significant. The benefits of the amelioration expressed in absolute figures have been easily observable until now. Recently, the importance of these benefits has decreased after the adaptation of planted trees to the mountain site and natural acceleration of their annual increment.

Structure and functions of the types of Norway spruce (Picea abies[L.] Karst.) roots

R. Gebauer, M. Martinková

J. For. Sci., 2005, 51(7):305-311 | DOI: 10.17221/4566-JFS

The aim of the study was to describe variability of the structure of roots in Norway spruce (Picea abies [L.] Karst.) from their growth tips to the stem foot, i.e. anchor roots in relation to their changing functions. Histology and anatomy of plant organs were dealt with by the innumerable number of authors and fundamentals of knowledge in these disciplines have become the self-evident part of botany textbooks. The description of primary and secondary structure of roots is explained in many textbooks by means of drawings depicting the mutual position of particular systems of tissues. However, it refers mostly to the structure of herb roots in either Magnoliophytes or Liliophytes. Naturally, the structure of tree roots does not substantially differ from herb species. A certain problem is related to the secondary thickening of roots, their ramification, anastomosis and changes in the structure which are enforced by tension and pressure forces; these forces affect the roots during their mechanical load, e.g. by solifluction, soil load and compaction or through their above-ground systems. Trees can be stressed by wind gusts, snow cover, glazed frost and a number of other factors. Therefore, the structure of roots changes in the course of time as well as due to the increasing weight of the stem and crown. In terms of histological structure Norway spruce roots were studied within a forest stand in the area of the Křtiny Training Forest Enterprise, viz. Vranov Forest District (49°19´484´´N, 16°47´629´´E). Root systems were exposed with an air blast using the AIR-SPADE tool (nadezhdina, čermák 2003) and cuts of buttress roots, horizontal roots, root anastomosis and fine roots were selected. Histological studies were focused on manual transversal cuts of fine roots.

The occurrence of fungal and insect pests in riparian stands of the central Hron and Slatina rivers

J. Kodrík, M. Kodrík, P. Hlaváč

J. For. Sci., 2006, 52(1):22-29 | DOI: 10.17221/4483-JFS

The paper deals with the occurrence of fungi and rusts, viruses and insects on main woody species in riparian stands along the middle courses of the Slatina and Hron rivers in Slovakiain 2002-2004. Forty fungal species, rusts and viruses and 79 insect species were found. The highest number of fungi occurred on the branches and twigs of poplar where Cryptodiaporthe populea (Sacc.) Butin and Phellinus igniarius (L.) Quél. had the highest representation and so the influence on the health condition. Melampsora alliipopulina Kleb., Poplar mosaic carlavirus, Venturia po-pulina (Vuill.) Fabr. and Venturia tremulae Aderh dominated on the leaves. The most frequently present fungus on the aspen was Armillaria sp., Phellinus igniarius (L.) Quél., on the alder a new hybrid from the genus Phytophthora - alder Phytophthora, Valsa oxystoma Rehm., Inonotus radiatus (Sowerby) P. Karst. and Inonotus obliquus (Fr.) Pilát. From the insect species Melasoma vigintipunctata Scop. and Phyllodecta vitellinae L. caused total defoliation on willows. The highest occurrence on the black poplar was on the leaf stalks represented by Pemphigus spirothecae Pass. species, on the alder it was Cryptorrhinchidius lapathi L. on the twigs and Agelastica alni L. on the leaves.

Logging and forest decline effects on the surface humus horizons in the Šumava Mts.

V. Podrázský

J. For. Sci., 2006, 52(10):439-445 | DOI: 10.17221/4524-JFS

Holorganic layers belong among the key ecosystem components of forest soils at higher altitudes. Increased biological activity of the surface humus is very often observed after forest decline and/or forest cut and removal at these sites. The forest removal or tree layer extinction was studied in the flat, water affected terrain: its effects on the soil chemical characteristics and on the soil respiration, ammonification and nitrification activities. The standard methods of analyses were used. The study proved the increased intensity of nitrification and ammonification in stands with decreased ecological as well as environmental function potentials, further decreased concentrations of magnesium. Due to the concentration effects, the concentrations of some macroelements - nitrogen, calcium - increased in these stands (in the humus form layers), as well as the base content and base saturation.

Effect of forest liming in the Western Krušné hory Mts.

V. Šrámek, J. Materna, R. Novotný, V. Fadrhonsová

J. For. Sci., 2006, 52(20):S45-S51 | DOI: 10.17221/10159-JFS

In May 31, 2000, the Government of the Czech Republic, has adopted the Decision No. 532, assigning the minister of agriculture to realize liming and fertilizing in the Krušné hory Mts. and Orlické hory Mts. Based on the decision, in 2000-2003, liming of forest stands was done, at the area of 34,000 ha. Changes of soil and leaf chemistry two years after liming were studied in the Western Krušné hory Mts., Forest administration Horní Blatná. Slight pH increase layer was stated both in the humus layer, and in upper horizons of mineral soil. Increased contents of calcium and magnesium, same as nitrogen and potassium were also recorded. Content of basic cations, mainly of magnesium and calcium, in the sorption complex was increased, aluminium content was decreased. C/N ratio in the humus layer did not change, ratio of basic cations and aluminium in the humus layer was increased significantly. Analyses of the assimilation organs of spruce have proved increase of magnesium and calcium content. The increase was higher in the stands of originally lower values of these elements. While before liming, in about a half of the samples of second needle year class, magnesium was under the deficiency level, two years after liming no deficient values were recorded.

Assessment of long-term tending in mixed stands of spruce, fir and beech on research plot KorytnicaOriginal Paper

I. Štefančík, L. Štefančík

J. For. Sci., 2002, 48(3):100-114 | DOI: 10.17221/11862-JFS

The paper deals with problems of thinnings in a mixed stand (spruce-fir-beech) situated in the sixth altitudinal forest zone. Three of the five investigated plots were tended by free crown thinning for a long time, and two were left without any planned silvicultural treatments as control. Dynamic changes in tree species composition, stand structure, qualitative and quantitative production were evaluated for a period of 30 years. The changes were compared with respect to differences between the plot with long-term silvicultural treatments and the control plots (without treatments).

Variation of the tree ring micro-hardness demonstrated on spruce wood

V. Mareš, J. Blahovec

J. For. Sci., 2004, 50(3):135-141 | DOI: 10.17221/4608-JFS

Micro-hardness was used for the study of wood structure (Norway spruce) in the line perpendicular to tree rings (radial surface). The steel indentor 0.25 mm in diameter with flat head was used for this purpose. The individual penetration tests were performed at constant velocity 0.0167 mm/sinto a depth of 0.3 mm. Local wood strength was defined as the mean pressure on the indentor head at 0.02 mm penetration. The set of tests (~ 320) gave information about stress variation in dependence on the location of the test place in the tested surface. The stress was understood as a parameter describing the growth properties of wood similarly like the density usually used in dendrochronology. The measured strength variation is in agreement with visually observed tree rings. The acquired data made it possible to determine the mean characteristic points of the tree ring as well as the development of the parameters in dependence on the weather variations.

The effect of stress factors on birch Betula pendula Roth

D. Kaňová, E. Kula

J. For. Sci., 2004, 50(9):399-404 | DOI: 10.17221/4636-JFS

In a controlled pot trial, plants of birch (Betula pendula Roth) were treated in six variants: acid watering (pH 3), acid watering with spraying, drought, ammonium sulphate fertilisation, ammonium sulphate fertilisation in combination with drought, and control. The response to the treatment with ammonium sulphate in terms of the increment was discordant as it increased the sensitivity of birch to frost. Drought had a negative effect on increments. A combination of ammonium sulphate and drought; drought; ammonium sulphate and sprayed acid watering delayed the shedding of leaves; this was due to a longer vegetation period, significantly higher nitrogen content in these variants, with the exception of drought.

The host spectrum of Dothistroma needle blight Mycosphaerella pini E. Rostrup - new hosts of Dothistroma needle blight observed in theCzech Republic

M. Bednářová, D. Palovčíková, L. Jankovský

J. For. Sci., 2006, 52(1):30-36 | DOI: 10.17221/4484-JFS

Dothistroma needle blight Mycosphaerella pini E. Rostrup and its anamorphic stage Dothistroma septospora (Dorog.) Morelet was detected for the first time in the territory of the Czech Republic in a consignment of imported plants of Austrian pine Pinus nigra Arnold in 1999. In 2000, it was also found on Pinus nigra in an open planting in a plantation of Christmas trees by the village of Jedovnice near Brno in South Moravia. In the Czech Republic, Dothi-stroma needle blight was identified on 13 species of pine. Pinus nigra Arnold and Pinus mugo Turra are the most frequent hosts. In addition to these species, Dothistroma needle blight was observed on Pinus ponderosa Douglas ex Lawson, Pinus jeffreyi Grev. et Balf, Pinus banksiana Lamb., Pinus contorta Douglas, Pinus rotundata Link, Pinus leucodermis Ant. and Pinus sylvestris L. Finds on Pinus aristata Engelm., Pinus rigida Mill., Pinus heldreichii H. Christ. and Pinus cembra L. var. sibirica (Du Tour) G. Don. are a certain rarity. These species are not mentioned anywhere as potential hosts of Dothistroma needle blight. As for the species of other genera Picea pungens Engelm., Picea abies L. Karst. and last but not least Picea schrenkiana Fisch. & C. A. Mey were also observed as hosts. The host range of Dothistroma needle blight recorded in papers is noted as well.

Effects of different pressing conditions on properties of spruce plywoods

P. Král, J. Hrázský

J. For. Sci., 2006, 52(6):285-292 | DOI: 10.17221/4510-JFS

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.

Biologically degradable oils at working with power saws

A. Skoupý

J. For. Sci., 2004, 50(11):542-547 | DOI: 10.17221/4654-JFS

Power saws require a relatively large amount of oil for their operation the reason being idle lubrication of the cutting chain. Oil leakages in the environment can result in soil and water contamination and are known to impact both flora and fauna. Many countries in Europe struggle to minimize the damage by imposing the use of biologically degradable oils for these purposes. The work presents an assessment of these biologically degradable oils from the viewpoint of their possible occurrence in environment and from the viewpoint of their technical characteristics which affect reliability and economy of working with power saws. Oil dispersion is evaluated especially from the viewpoint of the concentration of its occurrence on the soil surface after cutting with the power saw. Technical properties evaluated include heat-oxidation stability and pumping properties of oils at low temperatures. There are original methods of measurement developed for these purposes, which facilitate high repeatability of results. The effort aims at oils with core technical parameters at least comparable with mineral oils used so far, which would represent a lesser burden on natural environment.

Green alder effects on the forest soils in higher elevationsOriginal Paper

V. V. Podrázský, I. Ulbrichová, I. Kuneš, J. Folk

J. For. Sci., 2005, 51(20):38-42 | DOI: 10.17221/11847-JFS

Presented study documents the effects of green alder (Alnus alnobetula [Ehrh.] C. Koch) on the uppermost forest soil layers in mountain areas, respectively in the top part of the Orlické hory Mts. Three variants effect to the forest soil have been studied: pure groups of green alder, pure groups of Norway spruce and Norway spruce stand under-planted by green alder. The effect of alder stands litter influenced some basic soil characteristics: the surface humus accumulation (low), the bases content and base saturation (decreased). The green alder increased the acidification trends in the forest soils of the humus forms on the studied locality and intensified the mineralization and nutrient losses from the soil profile.

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.

Forest topsoil organic carbon content in Southwest Bohemiaregion

E. Cienciala, Z. Exnerová, J. Macků, V. Henžlík

J. For. Sci., 2006, 52(9):387-398 | DOI: 10.17221/4519-JFS

The aim of this study was to evaluate organic carbon content (SOC) in the surface layers of forest soils in the two Natural Forest Regions situated in Southwest Bohemia, namely Západočeská pahorkatina (NFR 6) and Český les (NFR 11). The study is based upon on two consecutive soil sampling campaigns during autumn 2003 and 2004. While the sampling of 2003 was inadequate to estimate bulk density, the consecutive campaign used a defined sample volume to permit an estimation of bulk density and quantification of soil organic carbon (SOC) for soil organic layers and the upper mineral horizon. The total sampling depth was 30 cm including both organic and mineral layer. SOC of organic horizon was on average 1.99 kg C/m2. It differed by stand site type ranging from 0.70 to 3.04 kg C/m2. The organic layer SOC was smallest under beech (1.03 kg C/m2), whereas it was higher under pine (2.19 kg C/m2) and spruce (2.09 kg C/m2). SOC in the mineral layer was in average 7.28 kg C/m2. SOC differed significantly by the major tree species and reached 10.6; 5.67 and 7.5 kg C/m2 for beech, pine and spruce sites, respectively. The average SOC for the total soil layer (0-30 cm) reached 9.33 kg C/m2. The methodological aspects of regional estimation of SOC and the potential of utilization of the national forest inventory program are also discussed.

Fertilizing and liming in a heather area of Norway

K. J. Erstad

J. For. Sci., 2006, 52(20):S52-S57 | DOI: 10.17221/10160-JFS

In a 6 years' field experiment in a podzolized heather area in Norway the effects of liming and P and Cu fertilization were tested versus changes in vegetation and soil chemistry. The vegetation altered slowly, particularly the woody species, but pronounced over years. Liming had a positive effect on all species except Deschampsia flexuosa and Vaccinium myrtillus, P tended to favour all except V. myrtillus, and Cu promoted all except Nardus stricta, V. oliginosum and V. myrtillus. Surface spreading of liming material and fertilizers caused distinct lime, phosphorus and copper effects and interactions in the soil litter layer. Liming markedly increased pH and Ca level and stimulated microbial activity, whilst the fertilizers increased P and Cu availability in soil. Cu fertilization counteracted a feared Cu deficiency when liming marginal soils. Gradually the changes penetrated into deeper soil layers. This strong chemical influence led the podzol into a cambisol cycle, characterized by retention of humus in the E layer, accompanied by a slight increase in pH, elevated levels of Kjeldahl-N, AL dissolved and exchangeable Ca, and in CEC and BS.

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.

Spontaneous infiltration of broadleaved species into a spruce monoculture left without tending

P. Jelínek, P. Kantor

J. For. Sci., 2006, 52(1):37-43 | DOI: 10.17221/4485-JFS

An experimental stand was established as a monoculture by planting Norway spruce on a clear-felled area in 1925. In 1958, a research thinning experiment was established there. Control plots and the study of their development without anthropic interventions are of interest in particular. The spruce monoculture nearly disintegrated and the stand-forming role was taken over by species which occurred there originally as admixed ones. The stand became sparser and it was associated with the spontaneous regeneration of broadleaves. Out of the eight control plots three plots were selected differing significantly in stocking and extent of natural regeneration. The development of regeneration was studied in detail on these plots. The undergrowth consisted of 24 woody species in a total number of 6,000 individuals per hectare and about two thirds of them belonged to trees. The results of the study show a possibility to convert a spruce monoculture to a broadleaved commercial forest using the spontaneous regeneration of trees.

Growth of Austrian pine (Pinus nigra Arnold) treated with soil conditioners on Loket spoil bank

P. Bulíř

J. For. Sci., 2006, 52(12):556-564 | DOI: 10.17221/4536-JFS

The effects of soil conditioners Frisol, TerraCottem, Bi-algeen, and fertilisers Silvamix Forte and Cererit on the welfare of Austrian pine were observed in a seven-year experiment on Loket spoil bank. Simultaneously the economic aspects of growing the Austrian pine until the stage of established plantation were examined. The application of products one year and a half after planting did not cause seedling mortality. The elongation growth of young plants conditioned by the application of Silvamix Forte and Frisol was statistically significant whereas these effects manifested themselves in the second year: they persisted till the end of the experiment for Silvamix Forte, and for three years in total for Frisol. The other products - TerraCottem, Bi-algeen and Cererit - also showed generally better, though statistically insignificant results as compared to those of the control plants. The elongation growth for all products culminated in the fifth year and then declined. The stem diameter growth for the best products reached its maximum in the second year. Regarding the overall height growth after seven years, the average number of the highest plants on the experiment location was on plots treated with Silvamix Forte; these plants exceeded the control plants by 46.2 cm. Pines treated with Frisol were higher by 23.4 cm. However, the application of soil conditioners and fertilisers to the given location proved economically ineffective because there was no need to improve the soil at the location, the same applies to mowing and hoeing since almost no forest weed grew there and the substrate surface remained well-aerated and porous.

Actual status of the beech bark necrotic disease in NorthWestern Bulgaria

A. Cicák, I. Mihál, Ch. Tsakov, P. Petkov

J. For. Sci., 2006, 52(5):226-232 | DOI: 10.17221/4505-JFS

In this paper we present recent findings about the beech bark necrotic disease in selected localities situated in the mountain ranges Vitosha and Stara planina in Bulgaria. The resulting values of necrotic disease expressed by the necrotisation index (ISN) ranged from 0.72 to 1.12. In Slovakia such low values of ISN were obtained only for seven out of 52 examined localities. The ISN results are more favourable than the results obtained using the same methods for four localities situated in Northern Hungary (ISN values ranging from 1.11 to 1.18). The results of monitoring of three selected biotic vectors of beech necrotic disease were follows: the focus of occurrence of the species Bucculatrix ulmella was in submountain beech forests. Considerable affinity to lower situated sites was found in Ectoedemia liebwerdella. We also found that the boundary of the occurrence of this species is approximately at 1,000 m a.s.l. The frequency values of Cryptococcus fagi were significantly influenced by the altitude. In four out of six localities we recorded the occurrence of three species of the genus Nectria: Nectria cosmariospora, Nectria galligena and Nectria coccinea.

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.

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.

Application of image analysis in plant pathology and forest protection

P. Čermák, P. Mazal, D. Palovčíková, L. Jankovský

J. For. Sci., 2006, 52(7):316-323 | DOI: 10.17221/4513-JFS

By means of computer-based image analysis it was possible to accelerate and automate a number of originally time-consuming activities in plant pathology and forest protection. In 1997-2005, image analysis was applied to the measuring of the size of colonies of fungi in vitro, feeding mark area, mass measuring of the size of spores and other microscopic objects, assessment of the progress of rot in a stem etc. The paper brings particular examples of the application of image analysis including methodical procedures and examples of research results obtained using Lucia G and Quick Photo Micro programs.

Effects of overstory structure and fire regime upon diversity and abundance of selected understory species in longleaf pine (Pinus palustris Mill.) forests in southeastern Georgia

W. Keith Moser, Chui Kwan Yu

J. For. Sci., 2003, 49(9):395-402 | DOI: 10.17221/4787-JFS

We examined the impacts of variation in overstory structure and burning regime on understory vegetation in the longleaf pine (Pinus palustris Mill.) forest of the Okefenokee National Wildlife Refuge in southeastern Georgia, U.S.A. On sandy upland sites surrounding the Okefenokee Swamp and on islands, we established five randomly-located 0.04-ha plots within each of six study areas. The plots varied in overstory density, past management and fire regime. We measured overstory tree size of longleaf pines in the 0.04-ha plots and percent cover of ground cover species in five 1-m2 subplots nested within each 0.04-ha plot. We also calculated diversity indices for the ground cover species. There was no significant relationship between overstory basal area and any diversity measure. Even at the subplot level, there was no significant relationship observed between the diversity measures and distance to the nearest tree, presumably a surrogate for overstory density. The diameter (DBH) of the nearest tree exhibited a slight influence over the Shannon Index, and the nearest tree's height was significantly related to evenness in each subplot. There were varied relationships between individual species and fire regime or nearest tree measurements. There was a definite, but statistically insignificant, trend of decreasing diversity with increasing years since the last burn. Height of the nearest tree positively influen­ced evenness, probably reflecting the influence of stochasticity and amount of needle deposition (influencing fire behavior) over a wide area. Within the generally equal fire-return interval across sites, individual fire-events and site-specific behavior apparently influence understory diversity. It is not surprising that the last burn would affect species richness, even more so than the number of growing-season burns, other studies support this observation. The presence of obligate seeding and (clonal) sprouting as dominants in the ground cover suggests that the fire-return interval is not regular. The cycling of fire-return intervals, even within the manage­ment-prescribed 2- to 4-year range, and the variation by microsite appear to provide sufficient variability of disturbance to create diversity in the ground-level cohort. Site-specific relationships between particular species and the nearest tree suggest that even a narrowly-prescribed fire management regime can provide sufficient diversity.

Changes in humus forms in gaps of the canopy of semi-natural beech stand

V. V. Podrázský, J. Remeš

J. For. Sci., 2006, 52(6):243-248 | DOI: 10.17221/4507-JFS

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.

Recreational load as a driving variable for urban forests

I. Kupka

J. For. Sci., 2006, 52(7):324-328 | DOI: 10.17221/4514-JFS

Green areas and urban forests represent important factors of urbanized environment which attracts more and more attention of forest management and silviculture. Recreational load and its types are the most important driving variable for the management framework in which basic silvicultural methods should be applied. The problem of the required combination of natural and social limits is resolved by a matrix which takes into account forest ecosystem quality and recreation. The matrix defines 9 or 27 units (their number depends on the fact if we take into account the age of stand or not) for which basic management rules could be prepared. The basic rules concerning biological aspects are described in a general way in the article.

The role of root system in silver birch (Betula pendula Roth) dieback in the air-polluted area of Krušné hory Mts

O. Mauer, E. Palátová

J. For. Sci., 2003, 49(5):191-199 | DOI: 10.17221/4693-JFS

120 root systems and trunks of 20 years old birch trees and 60 root systems and trunks of 15 years old birch trees affected by defoliation and with no visual symptoms of damage were analyzed in the air-polluted area of Krušné hory Mts. In the given area, birch develops a superficial or anchoring root system of circular shape. A greater effect of defoliation was recorded in trees with the superficial root system. The defoliation was in correlation with the extent of bole rot, root system rot and rooting depth. The proportion of root system branches infested by rot increased with increasing defoliation. Dominating fungi on roots were Armillaria gallica and Armillaria ostoyae. The degree of defoliation was directly proportional to the extent of bole rot induced by Trametes confragosa and Armillaria gallica, infecting frost ribs in the trunks. Extensive defoliation was recorded if more than 25% of peripheral tissues of the trunk and over 15% of root system branches were infected by rot. The defoliated trees showed a marked loss of fine roots, impaired longevity of fine roots and a change of ectomycorrhiza into ectendomycorrhiza.

Composition of psocid taxocenoses (Insecta: Psocoptera) in dependence on the level of naturalness of forest ecosystems in the Žďárské vrchy hills

P. Mückstein, O. Holuša

J. For. Sci., 2003, 49(5):208-219 | DOI: 10.17221/4695-JFS

In 1999-2000 in the Protected Landscape Area (PLA) Žďárské vrchy hills the occurrence of psocids (Psocoptera) was studied in different types of biotopes: natural forest ecosystems (stands of Fagus sylvatica with individual admixture of Abies alba, Acer pseudoplatanus, Picea abies), changed forest ecosystems (monoculture of Picea abies), young plantations in forest stands, disperse forest vegetation (solitary trees), and also non-forest ecosystems - agrocenoses, meadows and grazing lands. A total of 10,560 adults in 20 species were found. Three groups of biotopes with specific psocid taxocenosis were found out by computed cluster analysis - l. natural forest stands with dominance of Fagus sylvatica, 2. disperse tree vegetation and solitary trees in cultural landscape, and 3. forest stands remote to nature (monoculture of Picea abies). Occurrence of psocids was observed from the beginning of May to mid- November. Maximum of abundance was found in September.

Biological and chemical amelioration effects on the localities degraded by bulldozer site preparation in the Ore Mts. - Czech Republic

V.V. Podrázský, J. Remeš, I. Ulbrichová

J. For. Sci., 2003, 49(4):141-147 | DOI: 10.17221/4689-JFS

Biological and chemical (fertilising, liming) amelioration are among the principal tools used to restore degraded sites. These techniques were also used on the Ore Mts. plateau on plots prepared by bulldozing. We evaluated the impact of these amelioration techniques by measuring tree species primary production and humus form restoration. Begun in 1983-1985, this project studied growth reaction of forest stands by measuring height and diameter increment, for the following species (blue spruce Picea pungens Engelm., European larch Larix decidua Mill., lodgepole pine Pinus contorta Dougl., Eastern white pine Pinus strobus L., alder Alnus incana Moench., European beech Fagus sylvatica L.) during the period 1994-2000. The growth potential by species decreases in the following order: larch, alder, lodgepole pine, white pine, blue spruce. Beech was almost exterminated by red deer browsing and the harsh climate; pines suffered heavily from browsing and bark stripping. Holorganic horizons were measured and basic soil chemical and mechanical characteristics were determined - pH, soil adsorption complex characteristics (using Kappen's methodology), content of the humus and total nitrogen, exchangeable acidity and plant available macronutrients, granulometric composition of mineral soil horizons. Our results confirmed the relatively long-lasting effects of soil amendments, as well as the amelioration effects of alder, and the relatively inhibiting effects of larch and blue spruce.

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.

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