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The paper presents the results of evaluating the growth and health of 20 different poplars from the Aigeiros group in 30-year populetum Leles on uninundated alluvia of the Latorica River in ecological conditions of the lowland Východoslovenská nížina. The populetum is situated on medium-heavy loamy soils in the group of forest site types Ulmeto-Fraxinetum carpineum. The results of evaluation document that out of the investigated poplar clones the poplars I-214, I-476, Blanc du Poitou, Flachslanden and P. nigra (Baka 5) had the best height and diameter growth and maximum volume production. Their health status was also very good. The lowest volume production was determined in P. nigra (009/66 ČR), I-455 and Grandis, and the worst health was found out in Grandis, P. nigra (Pavlovce 1) and P. nigra (Ivachnova 1). These results will facilitate to include the poplars I-476 and Flachslanden in the assortment of regionalized poplars for the lowland area of Východoslovenská nížina.

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.

The paper studies the effect of a single use of a textural fraction of dolomitic limestone (5.1 t per ha) on soil reaction (pH/KCl and pH/H2O) and the content of exchangeable Ca and Mg (in the soil layer of 0-30 cm or in F, H and A horizons) during a 6-year experiment under a mature Norway spruce stand and a 4-year experiment on a clear-felled area. The increase in pH culminated in the 3rd or in the 3rd-6th year of the experiment. Maximum effects were achieved applying the fine fraction of a particle size £ 1 mm. The coarse fraction of a particle size > 1 mm showed virtually negligible effects. The increase in Ca and Mg content culminated in the last 6th year of the experiment. Maximum effects were achieved applying fine fractions again. The effect of the coarse fraction was also virtually negligible. After 6 years, ma-ximum increase in all values under study occurred in the upper narrow F horizon while the increase rapidly dropped downwards.

In birch (Betula pendula Roth) stands of the Děčín sandstone uplands (northern Bohemia) 55 species of leafhoppers were captured using photoeclectors, ground traps and shaking down onto sheets (23,855 specimens of larvae and imagoes). The dominant representatives of the grass and herb undergrowth in birch stands are Jassargus allobrogicus, Anoscopus flavostriatus, Neophilaenus lineatus, Hyledelphax elegantula, Diplocolenus bohemani, Streptanus brevipennis, Macustus grisescens, Planaphrodes bifasciata and Cercopis vulnerata. A heavy abundance of the dominant Oncopis flavicollis and the less abundant O. tristis, weakens birch growth due to the leaf-sucking activities of the insects.

In three investigated stands the highest increment (8.8 m3/ha per year, i.e. 1.5% of the actual stand volume, measured at the end of the control period) was reached by Jawornik I stand in the initial period of the growing up stage, and Tworylczyk stand in the advanced growing up stage (7.4 m3/ha per year, i.e. 1.2% of the actual stand volume). Jawornik II stand, in the optimum stage, the aging phase, had the lowest increment (3.9 m3/ha per year, i.e. 0.7% of the actual stand volume). The process of a natural volume loss was the most intensive in Tworylczyk stand (7.6 m3/ha per year), a little less intensive in Jawornik II stand (7.1 m3/ha per year), and the least intensive in Jawornik I stand (5.8 m3/ ha per year). The analysis of tree loss, recruitment, and increment, and the relations between these processes, can form the basis for a conclusion that stable stands developed in the Carpathian primeval beech forests in the years 1988-1998. Such steady processes can be used for the development of a stable, multifunctional model of the forest managed by the selection system, or the Swiss irregular shelterwood system in the Carpathian beech stands of a similar structure.

The mycoflora was investigated under the conditions of climax spruce stands in the Krkonoše Mountains in relation to wood decomposition. The areas under observation have been affected more or less by air pollution since the eighties. The average mass of deadwood found on the plots is 124 m³ per ha - the mass of fallen trunks is about 32 m3 per ha, mean value from total average. About 128 species of macrofungi were identified that besides others included 43 species of wood-decaying fungi. Also 54 mycorrhizal species were identified. Among the mycorrhizal fungi about 10 species were dominant, such as Laccaria laccata (Scop.: Fr.) Cooke, Lactarius helvus Fr., Lactarius mitissimus Fr., Lactarius rufus (Scop.) Fr., Russula emetica (Schaeff.: Fr.) Pers. and Russula ochroleuca Pers. etc. Concerning the volume of decomposed wood on monitored plots in climax spruce stands, the prevalent wood-decaying fungi are brown rot fungi. The proportion of brown rot fungi in wood decomposition is 60-95% of deadwood mass on the plots of climax spruce stands. A dominant species is Fomitopsis pinicola (Sw.: Fr.) P. Karst. causing the brown rot. Concerning the group of white rot fungi, the most important is Stereum sanguinolentum (Alb. & Schw.: Fr.) Fr., participating by 17% in wood decomposition on plots damaged by deer.

Height and diameter growth and volume production of 22 different clones of poplars were evaluated in Sliepkovce populetum at the age of 12 years. The populetum is situated on medium-heavy and medium humic uninundated alluvia of the Laborec river; typologically, the group of forest types is Ulmeto-Fraxinetum populeum. The results of evaluation documented that among the poplars under study the clones Gigant, OP-229 and BL achieved the best growth and maximum volume production while their mean height amounted to 22.9-23.8 m, mean diameter to 31.9-33.2 cm and average annual volume increment was 25.1-28.3 m³ per 1 ha. The growth of P. Rochester 20/66 poplar was considerably much slower: its mean height amounted to 17.3 m, mean diameter to 18.7 cm and average annual volume increment was 6.3 m³ per 1 ha. It will be necessary to carry out further studies to obtain more detailed values for these clones.

The paper presents a method for the derivation of total timber production and of increments in value units, particularly in net financial yield for spruce stands damaged by crown defoliation after their dieback. The value production was derived by means of value growth models of undamaged stands and models for the adjustment of volume and qualitative production of damaged and died stands. Changes in timber quality after tree drying and changes in the production of damaged stands compared with undamaged ones are illustrated in tables and graphs. The changes are expressed by means of the indexes of total mean increment and total current increment. They depend mainly on the degree of stand damage expressed by crown defoliation, age and yield class of stand, the age of stand when the damage started and duration of damage. The value of damaged stands after their dieback is lover minimally by 50% than before their dieback. It is caused mainly by deteriorated quality of timber from dead trees in stand.

The results document changes in the herb vegetation of a South-Moravian floodplain forest in the period of 1978-1997. It is shown that hydrological measures strongly changed the floodplain forest in the area of the Dyje river near Lednice na Moravě. The herb vegetation in the area of the confluence of the Morava and the Dyje rivers was conserved nearly unchanged after artificial floods.

From the economic point of view the issue is comprehensive namely for its long-term character. At present, there is little experience in complexly understood economic calculations concerning the effect of climate change on forest management. Therefore a new methodology had to be proposed to solve the assigned task, i.e. to analyse the results of research on the effect of climate change on forest management. The issue is closely related to changes in production characteristics of commercial species, i.e. site quality and species composition or health conditions and rotation period of each species and stand. In this case it concerns with a higher proportion of deciduous species at the expense of conifers, namely spruce. This issue also includes the question of further afforestation of non-forest agricultural land, that means the question of land delimitation between agriculture and forestry.

This paper evaluates the development of growing stock, number of trees and diameter distribution of the standing volume in the Opuky locality where conversion to a selection forest has been the aim of management over a long period of time. With respect to species composition, the stand is divided into two plots. The initial condition and development of both plots differed. The favourable initial composition of the stand has gradually deteriorated due to delay in natural regeneration and therefore recruitment of young trees over a long period. The total number of trees on both plots has been low for target diameter of 51 cm. On the other hand, the growing stock has exceeded the model condition. The proportion of broadleaved species in the stand gradually increases, reducing the possibility of conversion to a selection forest in future.

Differentiation of forest technologies according to ecosystem properties is a necessary step to achieve sustainable forestry. A forest typological system is considered to be the basic unit of ecosystem differentiation in the Czech Republic. Terrain characteristics, potential water erosion and applicable harvest technology were examined for 44 forest sites in a landscape segment of the Jizerské hory Mts. Forest site was found homogeneous in terms of terrain and technological properties. Edaphic category and groups of forest types as higher classification units and management sets as units of alternative classification showed lower homogeneity insufficient for operational planning.

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).

The article deals with issues of non-market forest services. There is a persistent issue complicating the quantification of adequate subsidy to forest owners - non-existence of market with such forest services. Forest services financing can be made objective by implementation of the following steps: 1. Earmarking of non-market forest services that are becoming market subjects gradually. 2. Earmarking of non-market forest services that create a secondary product of wood production function. 3. Quantification of demand for services. 4. Quantification of costs necessary to cover the demand for those forest services. 5. Quantification of losses caused to forest owners by restricting their economic activities.

Age and diameter classes or growth stages as criteria for the implementation of thinning

Natural regeneration is an important part of close-to-nature forestry. However, natural regeneration also has either natural or technological limits. Among the most important natural limits are a low sum of precipitation and site type. The study concentrates on Žatec region where the long term average sum of precipitation is only 440-450 mm per year. Dry periods during the vegetation time are quite frequent. The study was conducted on clear cut area, stand edge, shelterwood area and stand interior. The results showed the highest population densities in a shelterwood system, the lowest in the stand interior. On the other hand, the dry seedling biomass is lower for seedlings from shelterwood area than from clear cut area.

A grown-up specimen of Juglans ×intermedia Carr. walnut was accidentally found in the stand of black walnut (Juglans nigra L.) in the Židlochovice Forest Enterprise in the forest district Velký Dvůr, Stand No. 224 D10. The tree was photographed, leafy shoots and fruits were sampled for later analyses. The paper brings a description of growth habit, rough bark, morphology of leaves, current year shoots and fruits. Discussed are dissimilarities from the parental species (J. nigra and J. regia L.).