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Surface ozone is considered to be a very phytotoxic gaseous air pollutant. Its negative impacts at both the cell and the organ level have been shown, mainly as a result of experiments. However, the demonstration of ozone negative impacts on native plants is not explicit. An assessment of ozone impact on vegetation and ecosystems using indicators based on ambient ozone concentrations is insufficient and assessment techniques based on internal ozone dose and on real plant damage are more appropriate. Such a possible technique is the mapping of ozone visible symptoms due to ozone influence. The ICP-Forest method concerning ozone visible symptoms and the assessment of ozone influence were applied for the purposes of this case study. The visible symptoms are characterized by a few typical signs. Nevertheless, the identification of visible symptoms in native conditions can be problematic and misleading conclusions could be drawn. Therefore it is necessary to complete the identification of visible symptoms with a validation in order to confirm ozone as the cause of plant injury.

The study analyses the growth of beech seedling fine roots and their development in the first five years. The research plots were established in 1997-2003 in community forests of Starý Plzenec (Western Bohemia, Czech Republic). The data are based on annual reviews of beech samplings extracted from surveyed plots. The whole root volume as well as the fine root volume is significantly (on a 95% significance level) growing during the first years after outplanting and there is not any disruption of growth immediately after outplanting.

The degree of the beech bark necrotic disease was evaluated in three selected localities in southern Poland, in different orographic complexes, Beskid Sądecki, Beskid Niski, and Bieszczady. The degree is expressed by means of the stem necrotising index (I_SN ), crowns necrotising index (I_CN ), and whole tree necrotising index (I_NWT ). The values of the indices laid in the following limits: I_SN 0.73-0.84%, I_CN 0.12%-0.51%, and I_NWT 0.84%-0.90%. The current status of the beech necrotic disease in Southern Poland can be considered as favourable. The values of I_SN recorded in Southern Poland were lower by 30% than the average I_SN for whole Slovakia. We also recorded the frequency of selected insect pests (Bucculatrix ulmella Zeller, Cryptococcus fagi Bärensp., and Ectoedemia liebwerdella Zimm.), which act in the beech stands as vectors of the necrotic disease. With C. fagi, we recorded a high frequency reaching even 100%. In contrast, we did not at all observe the occurrence of B. ulmella and E. liebwerdella, which are common in the beech stands in Slovakia, as well as in Hungary, Romania, and Bulgaria. In the localities studied, we recorded the occurrence of two species of parasitic fungi of the genus Nectria (Fr.) Fr. causing the beech bark necrotic disease, viz. Nectria cosmariospora Ces et De Not. and N. galligena Bres. ex Strasser.

The influences of long-term flooding and Phytophthora alni subsp. alni infection on the growth and development of 4-year-old Alnus glutinosa (black alder) saplings were investigated. The black alder saplings were divided into four groups and then subjected to combinations of both factors - flooded and inoculated with pathogen, flooded non-inoculated, non-flooded inoculated, and control. The biomass of the living roots and actinorrhizae, increase in stem length, length of leaves, rate of chlorotic foliage, amount of foliage biomass and length of stem necrosis were assessed after seven weeks. Both factors, flooding and P. alni infection significantly affected the black alder. In addition, a significant effect of interaction was observed. The inoculated flooded group had a substantially lower biomass weight of living roots, actinorrhiza and leaves than the other groups. The necroses caused by the pathogen in the flooded group were more extensive than those in the non-flooded one. These findings demonstrate that the simultaneous incidence of stress caused by flooding and P. alni infection is highly dangerous for black alder.

Studies were carried out during 1987-1997 in four stands situated in the lower mountain zone, and representing the association Carici-Fagetum abietetosum (sample plots Facimiech and Walusiówka) and the community of a transitory character between Dentario glandulosae-Fagetum and Carici-Fagetum (sample plots Gródek and Przelecz Sosnów). The greatest volume increment was found in a pure fir (Abies alba) stand of Facimiech (9.4 m³/ha/year, i.e. 1.4% of actual stand volume determined in 1997) being in the optimum stage, phase of aging and regeneration, and the smallest one stand of Gródek (5.3 m³/ha/year, i.e. 0.9% of actual stand volume) being in the growing up stage, phase of selection forest. The stand of Przelcz Sosnów was characterized by the greatest mortality of trees (volume of loss, i.e. 13.5 m³/ha/year). In this stand of a transitory character between the growing up and optimum stages, due to rapid mortality of fir the break up of the stand took place, and in consequence the growing up stage, phase of a little diversified stratified structure was developed. Volume of recruitment was the greatest in the stand of Facimiech, i.e. 0.05 m³/ha/year. In three fir (Abies alba)-beech (Fagus sylvatica) stands the proportions of fir and beech in stand increment differed from their proportions in stand volume. The percentage of fir in volume increment was smaller, and that of beech greater, than their percentages in stand volume. Processes of increment and mortality of fir and beech pointed to a progressive process of changes taking place in stand species composition, expressed by the increase of beech and the decrease of fir. The knowledge about values of loss, recruitment, and increment, expressed by the number of trees and volume units, may be of help in determination of the amount of cut in productive and protective forests managed according to a close-to-nature silviculture.

The basic feature of an economic reform of the forestry in the Czech Republic after 1990 was separation of supervision in the state forests from operating performance. The Forests of the Czech Republic, state enterprise, was charged with management and supervision, hence economic activities of the subject are provided on the basis of contracts by entrepreneurial units called contractors in the forestry. The purpose of the paper is economic analysis of the Forests of the Czech Republic, state enterprise, in the period 1998-2002. The objective is the construction and testing of an elementary method of financial analysis as well as outline of financial situation and development of the chosen subject generally. The paper contributes to branch economy analysis, common in agriculture and wood-processing industry.

Altitudinal studies has become of interest to ecologists concentrated on functional alterations aiming to clarify the effects of limiting factors. Nutrient element release from forest floor (FF) decomposition is suppressed by those factors such as low temperature, shortened vegetation period concluding FF accumulation at high elevation fields. To draw out a response to the FF decomposition issue, FF layers as leaf + fermentation (L + F) and humus (H) were collected from 37 representative sample plots along an altitudinal gradient (from 1,400 m to 1,710 m) on Kaz (Balikesir-Turkey) mountain. Mass, pH, organic matter (OM) and total nitrogen (Nt) contents of FF were investigated to explain the relation between decomposition and altitudinal effects. The results revealed that total FF mass and (L + F), (H) sub-fraction masses through elevation show an insignificant relation with the altitude. No significant difference was found between the altitudinal groups in the OM content of L + F. Besides there are significant negative correlations between OM contents (%) of L + F and H layers and altitude with the coefficient values 0.342 (P< 0.05) and 0.597 (P < 0.01), respectively. The Nt content of L + F layer also increases through the elevation revealing a medium correlation with altitude (0.368; P < 0.05). The increasing Nt and decreasing OM contents show better decomposition rates at higher sites regardless of the altitude induced climatic changes. We assume that the forest floor accumulation under tree canopies provides a better decomposition relying on the microclimatic environment mediated by tree canopies, in spite of the altitude.

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.

The paper proposes a method of assessing the potential risks of the future development of stands in relation to a climatic change. To assess risks of the future development of a stand simple point scales have been worked up based on primary properties of a site and a stand according to data of the forest management plan (FMP). In assessing the health condition, the risk of damage to stands by Armillaria sp. in the felling age was evaluated on the basis of a present attack by Armillaria sp. and also defoliation of the crown primary structure assessed during a simple field examination. The evaluation was carried out in the region of the Křtiny Training Forest Enterprise (TFE) Masarykův les, ranger district Proklest, in 2002. The study was conducted in 118 Norway spruce stands aged more than 20 years. The majority of evaluated stands ranked among the category of high and medium risk from the viewpoint of site and stand risks and among the category of high Armillaria sp. attack.

The genetic variation in 20 provenances of European larch, growing under site conditions of the Beskid Sądecki mountain range (experimental area in Krynica), was investigated during a long-term study carried out within the 1967 Polish Provenance Experiment on Larch. Data consisted of diameter measurements taken outside bark on standing trees of the analyzed provenances. Results showed that there was no distinct variation in the tested larch populations in respect of stem form. Some differences between compared provenances in respect of stem taper and form factor were the result of differences in tree height and diameter.

The paper summarizes the results of institutional research aimed at new types of combined plywood materials. Under pilot plant conditions, three variants of combined plywood materials were pressed, namely with the layer of fibreglass, with a core cork layer and with a cork wear layer on one side of the plywood surface and a cork core. Tests of selected physical and mechanical properties were carried out on these materials including the basic statistical evaluation. Comparisons with plywood materials Multiplex 15 and 20 mm in thickness were also made.

In 25 to 40-years-old stands damaged by snow in the Beskids, the fauna of cambioxylophages was analyzed both on standing breaks and lying break-off stems. Breaks are characterized by the gradually drying phloem, watered phloem and secondary fauna (Hylurgops palliatus, Hylocoetes dermestoides, Dryocoetes sp., Monochamu sp.), which does not represent any danger to spruce stands. The phloem on lying breaks withered and died till the end of the growing season. The competing species Pityogenes chalcographus (L.) (46-52% cov-er) and species of the genus Dryocoetes (20% cover) colonized the breaks in particular. The upper and the lower side of the lying breaks-off differ in the intensity of attack and the degree of cover of these species. In young broken and open stands with the unprocessed wood of lying breaks-off there occurs a risk of the creation of bark beetle circles in the subsequent year after the damage.

The study is already the 5^th account on the production potential and stability of mixed forest stands in uplands. A spruce/beech stand established in the mid-30s of the 20^thcentury is assessed. The stand is situated at an altitude of 470 m and since 1960, it is left to its spontaneous development. At that time, the stand was characterized as a silviculturally neglected dense spruce young growth to a small pole-stage stand with an admixture of beech (spruce 71%, beech 13%). In the course of 41 years, spruce proportion in the stand without intentional thinning measures decreased from 71 to 56% and, vice versa, beech proportion increased from 13 to 31%. Present dominant and co-dominant position of spruce in the stand, its health condition and development in recent years indicate that the ecosystem under evaluation is stabilized fulfilling all functions on the given site at an age of 65 years. The stand is permanently fully stocked and its initial standing volume of 109 m³/ha at an age of 24 years in 1960 increased to 560 m³/ha at an age of 65 years in 2001.

This paper presents the results of investigations on natural forest regeneration in Norway spruce (Picea abies L. Karst.) monocultures in the Ukrainian Beskids with the use of FORKOME model prognostic possibilities. Different variants of regeneration methods are presented. Selective cutting with planting was determined as the most effective: spruce selective cutting with simultaneous planting of target species: beech (Fagus sylvatica L.) and fir (Abies alba Mill.) with admixture of ash (Fraxinus excelsior L.). Beech and fir biomass increases rapidly over the first 20 years - then it stabilizes. After another 20-30 years the initial form of beech forest is recognizable and it is possible to speak about an increase of beech forest, which in the course of time achieves a higher degree of similarity to natural stand. In the Ukrainian Beskids the potential forest stand consists of beech and fir (Dentario glandulosae-Fagetum).

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.

European larch (Larix decidua Mill.) is one of the most important tree species in substitute stands of the Krušné hory Mts. (northern part of the Czech Republic). At present, young larch stands have dynamic height growth and their canopy is closing. Therefore, the proper forest treatment with respect to all functions of these stands is an urgent issue. The aim of the study is to recognise when it is possible to start with thinning and what types of thinning regimes are more suitable in larch stands with respect to their functions as substitute tree species stands. Research was conducted on experimental series Kalek established in a larch monoculture in 1999 (stand age of 12 years) at an elevation of 780 m above sea level in the category Piceeto-Fagetum oligo-mesotrophicum - Calamagrostis villosa. The presented analysis has two main parts: (a) effect of closing canopy on growth of larch - comparison of the groups of trees from border and inside rows and (b) effect of opening canopy on growth and development of young larch stands - comparison of two partial plots (500 m² each): the one without thinning and the other with thinning (negative selection mainly from above at the age of 13 years). Comparative analyses of trees from border and inside rows showed high growth dynamics of these young larch stands, and therefore the first thinning is necessary in this stage (by 15 years of age). In spite of air pollution, the growth of experimental stands is supernormal and exceeds the data from growth tables, but 60% of individuals showed some malformations, mostly one-sided or two-sided stem curvature. Five years after the first thinning we found a significantly lower h/d ratio of mean stem on the thinned plot in comparison with the plot without thinning. On the other hand, the applied thinning had no effect (five years after realisation) on the h/d ratio of dominant trees (200 thickest trees per hectare).

The paper presents the results of relatively long-term research focused on spoil bank revitalization pro-cesses in the North Bohemian Brown Coal Basin after the first three years of observations. The biological activity of soil (namely catalase and phosphatase activity), indicators of basal and potential soil respiration, ammonification and growth, development and nutrition status of forest plantations were selected as indicators of this revitalization process. These parameters were determined in five localities of different age of reclamation where different technological approaches and tree species compositions were used. The results confirm the distinct time dependence of revitalization processes. From the aspect of biological activity older reclamations are close to natural forest soil. The enrichment of top soil layer with organic matter before the plantation (by ploughing in cellulose fibres and peat addition) increased some parameters of soil biological activity. The positive amelioration effect of black alder (Alnus glutinosa) was also confirmed.

High quality of planting material is an essential prerequisite for successful artificial forest regeneration. We carried out a detailed investigation aimed at differences between plantable bareroot and container plants of Norway spruce (Picea abies [L.] Karst.). Based on the results of this experiment, there exist marked differences in basic morphological traits between bareroot plants and plugs. The largest differences were observed in root collar diameter and root system volume. Differences in physiological quality (nutrient content, function of assimilatory organs) were also great. The results document that container seedlings of Norway spruce produced by intensive technology in controlled conditions of plastic greenhouses have very good predispositions for successful growth in difficult mountain conditions.

In this contribution we present the results of analyses of selected mineral nutrients in assimilatory tissues of spruce trees at different developmental phases (plants, adult trees) in the region Horný Spiš. The very close connection between mineral nutrient cycling and other physiological processes in the plants has been well recognised. The presented analyses of mineral nutrient cycling were done within comprehensive eco-physiological research assessing the physiology and health status of spruce stands in the study area. The research was conducted directly in the stand (Hliníky locality, Horný Spiš - two research plots: 1. plot with spruce stand in advanced decline, 2. control plot - without visible decline symptoms) and, at the same time as a pot experiment. The objective of the pot experiment was to verify the supposed negative influence of soil environment (in the locality with advanced decline of spruce stands) on the growth of spruce trees and their mineral nutrient conditions. The analyses of the material sampled from the stands revealed high amounts of manganese (MnT) that were in the toxicity range on both examined plots. Another negative finding was high amounts of toxic aluminium, primarily in needles of adult trees growing on the plot with symptoms of acute stand decline. This reflects a very low value of pH/H₂O - 3.7 (pH/KCl - 3 to 2.8) and total exhaustion of the soil suffering, moreover, from the lack of soil water. As for the differences in amounts of individual macronutrients between the plot with intensive decline and the control plot, no significant differences were found, with the exception of Fe. On the other hand, evident significant differences in risk elements Pb, Hg and Al were found. As for the differences in nutrient contents in spruce seedlings in the pot experiment (variants 1 to 6), we can see significant differences in macronutrient contents (N, P, Ca, K, Mn), in some cases also in risk element contents (Al).

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.

A dramatic forest decline due to the bark beetle outbreak, which occurs in the Norway spruce stands in the Western Beskidy (southern Poland) since 2003, was started after severe physiological drought during winter time. An analysis describing some spatio-temporal characteristics of this process, with special regard to the patterns of bark beetle occurrence related to root fungal diseases, is presented. In 2003 the bark beetle occurrence level assessed as high and catastrophic was recorded on 40% of the area, while in 2006 - on 59%. The range of Armillaria root disease and bark beetle outbreak increased towards higher altitudes, including the zone above 1,000 m a.s.l. The wind damage in 2004 and 2007, and high temperatures in the summer 2006, further stimulated the increase in bark beetle populations level. Some conclusions on possible development of the outbreak and recommendations concerning related needs in forest protection, are given.

: At present, the coppice-with-standards system has become so rare in floodplain forests that it is considered a natural monument. In 1990, the coppice-with-standards system was not recorded in the territory of the Czech Republic. This state contradicts the increasing interest of nature protection organizations in the relict remainders of the coppice-with-standards system, which is to be considered the closest to naturally preserved lowland forest type, and is, therefore, recommended as the final state of the biocentres and biocorridors in today's floodplain forests. The aim of this paper is to present the results of the inventory dealing with the present occurrence of the coppice-with-standards system in the floodplain forest of the Litovelské Pomoraví Protected Landscape Area (PLA) in a historical context.

Ecology of capercaillie (Tetrao urogallus) was studied in the mountains of Central Slovakia (West Carpathians) in 1981-2003. In the studied area, the capercaillie population inhabited especially old natural forests (100-250 years old) in the spruce-beech-fir (850-1,270 m a.s.l.) and spruce (1,250-1,530 m a.s.l.) vegetation zones. The overstorey stand age ranged between 80 and 250 years with the mean of 128 years. The understorey stand age ranged from 10 to 60 years. The overstorey tree density ranged between 200 and 1,050 stems per ha (mean 725). The understorey tree density ranged from 5 to 650 trees per ha (mean 290). Both males and females preferred old forests throughout the year. The results demonstrate a marked decrease (> 50%) in the numbers of cocks and hens on twelve monitored leks (28%) and a slight decrease (< 50%) on ten display grounds (24%). During the study period, capercaillie cocks became extinct on seven (16%) leks and in their surroundings. More or less constant numbers were found on twelve leks only (28%) and a slight increase occurred on two leks only (4%). A statistically highly significant correlation was found between the area of old-growth forest and the number of cocks attending a lek. In addition to forest deterioration predation appeared to be of major importance in limiting the numbers of capercaillies. Key points for forest management in relation to capercaillie protection are suggested.

The paper describes the regime and dynamics of the soil moisture content of sandy soils in Záhorská lowland during different growing seasons. Research plots are situated near Kamenný mlyn, approximately 3 km from Plavecký Štvrtok and 8 km southward from the town of Malacky. Changes in the soil moisture content are described by soil moisture constants (MCC, PDA, WP) and its relation to atmospheric precipitation and to the character of undergrowth is shown. The low water-holding capacity of sandy soils and their high drainage together with dense root system do not allow the sufficient saturation of soil during the growing season. The low wilting point value (2%) leads to the consumption of all available water in the soil. The most frequent is the semiarid interval of soil moisture (PDA -WP) with reduced availability of water to plants (> pF 3.1). The arid interval (< WP) occurrence on hot summer days results in a decrease in transpiration and assimilation intensity of plants, their physiological weakening and premature fall of assimilation organs.

In this study results of hydrogel application in reclamations are presented. The application of hydrogel affected the survival of pine seedlings during two vegetation periods after planting. Double application of STOCKOSORB AGRO (gel) on the root system after lifting caused an about 19% higher survival rate compared to control variants. The application of 7 g/planting hole of STOCKOSORB MICRO granules caused overdosage and plant mortality. The application of hydrogel granules is simple but it is very complicated not to cause the overdosage because of the very high swelling capacity of hydrogel. Research should be carried out to determine suitable hydrogel application rates for different environmental conditions and tree species. To design a technology with regard to the economic effectiveness of application will be a very important task.

The authors elaborated a new complex methodical approach to the evaluation of necrotic disease of beeches. They used two evaluation scales: a scale for the evaluation of stems and a scale for the evaluation of beech crowns. A four-degree scale for the evaluation of necrotisation of crowns completed the existing five-degree scale for the evaluation of necrotisation of stems. Combination of both these scales into one methodical approach produced the third, complex scale for the evaluation of necrotisation of whole trees. The proposed combined scale is recommended for the monitoring of beech necroses.

Geostatistical analysis of bark beetle activity and its use for the improvement of pest control measures are presented. Data on the volume of salvage timber felling due to bark beetle infestation for the period 2002-2004 were used for the analysis. Research was carried out in the northwestern part of Slovakia. The techniques used were variogram modelling, Turning Bands Simulation and selected techniques of simulation post-processing. The maps indicating the probability that a critical volume of timber felling was exceeded in a particular location were produced. The proposed system may be used effectively for the improvement of pest control measures and development of slow the spread strategies. The benefits and shortcomings of this approach in forest protection are discussed.

This paper deals with transformation of pure even-aged forest stands to uneven-aged irregular stands on an example of the Klokočná Forest Range. The fully operational management system according to principles of shelterwood or selection systems has been executed here since 1993. An investigation of this transformation process started in 1999 and it is focused on the places with more distinct structural differences. On the basis of research analysis, it is possible to consider about the permanent uneven-aged forest stands in future here. But for successful achievement of this goal it is necessary to continue this transformation step by step for a long time. The transformation is still at the beginning and its result depends on the effort and the forest management goal and the priority of the particular forest functions.

The root-plant ratio is one of the important parameters for planting stock quality. We suppose that the ratio is one of the driving variables for the growth performance of new plantation in the forest. The study summarises data on the volume of major parts of 4 years old wild cherry trees. An allometric analysis of different parts of plants in relation to the growth performance of wild cherry trees was done. The results show a close positive relationship between the volume of the whole root system and aboveground biomass. The same is true of the fine root proportion in the root system. Data also document that the efficiency of root system is not decreasing during the root development - at least in the investigated period. The same results were obtained for fine root efficiency. Data confirm the importance of the root-plant ratio for the growth performance of new plantation in the forest provided that harmful factors are not at a limiting level.

Seeds and seedlings of Quercus robur, a characteristic tree species of the hardwood floodplain forests along the Rhine River, demonstrated high resistance to complete inundation under controlled conditions. In both experimental trials no significant difference between the different flooding periods (8, 10, and 12 weeks) could be established either for shoot emergence or for the measured morphological growth parameters. Flooding delayed the germination of submerged acorns till the end of inundation. However, seeds of the flooding treatments had significantly higher germination rates than the non-flooded acorns of the control. Likewise, dry weights of seedlings from the flooded seeds were significantly higher than those of seedlings from seeds not flooded. Aboveground growth in the 24-week growth period following flooding was reduced in favour of root development in either trial of the experiment. Restricted leaf development and reduced shoot elongation stalled the growth of young oaks in the seedling trial. The results confirm knowledge from earlier experiments about the flood tolerance of Quercus robur seed and seedlings. They also serve to explain why oak seedlings are widespread on the Rhine floodplain after mast years, but gradually disappear in successive years.