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Net photosynthetic rate (A) and stomatal conductance (gs) of leaves of Nothofagus pumilio and N. an-tarctica seedlings were measured at different photosynthetic photon flux densities (PPFDs, 20, 150, 250, 500, 750, 1,000, 1,500 and 2,200 μmol/m²/s) and after 60 minutes of shade to determine the rate of photosynthetic induction after seedling transition from low to high PPFD. A and gs were also measured to evaluate the responses to water stress and the tolerance to waterlogging. N. pumilio had higher A values than N. Antarctica for all light intensities measured with the maximum value of 16.8 μmol CO₂/m²/s saturated at 1,000 μmol/m²/s PPFD. Values of gs for both Nothofagus species also declined as light intensity decreased. The times required for full induction of A were 18 and 27 minutes after the increase of PPFD (full sun) for N. pumilio and N. Antarctica, respectively. There was a negative relationship between A and water stress, expressed as pre-dawn leaf water potential (ψ_lp), where the reduction in gs was the main factor that reduced A in both species. Tolerance to waterlogging was related with changes in A and gs where N. Antarctica was more tolerant. These photosynthetic results of Nothofagus leaves to fluctuating light, water stress and waterlogging could be used to estimate the responses of regeneration to environmental conditions under the dynamics of natural stands, after silvicultural practices and for restoration plans.

The combination of georeferenced colour aerial photos and limited field measurements of individual trees was used to determine tree stand biomass in forests of prevailing Norway spruce. The technique was carried out in two localities - small catchments of natural lakes in the Bohemian Forest (56 and 76 ha in size, respectively). This method is not so expansive as the inventory based on sample plots, namely in the terrain of high dynamics in the mountains. Tree crown diameters were determined semi-automatically on the basis of orthophotos. The catchment of Plešné jezero Lake can be described by these average values: crown diameter 4.5 ± 1.35 m, mean tree height varying between 19.6 and 30.2 m depending on altitude (tree average and standard deviation are 25.5 ± 3.9 m), tree density 154 ± 67.7 ha and stand biomass 197 t/ha. The Čertovo jezero Lake catchment shows somewhat different values: crown diameter 4.9 ± 1.35 m, mean tree height varying between 20.9 and 25.1 m (dependence on altitude is weak; tree average and standard deviation are 25.6 ± 2.0 m), tree density 200 ± 65.7 ha (all parameters for Norway spruce only), and stand biomass 156 t/ha (Norway spruce) + 17 t/ha (European beech). Some features are common to both catchments: a regular to random tree pattern prevails. Tree clumping is typical of the most extreme stands. Minimum tree density occurs in the zone of the altitudes 1,200-1,250 m a.s.l. The crown diameter to dbh ratio is independent of altitude. Tree height decreases linearly with altitude. The distribution of trees according to crown diameter is skewed to higher values.

This study was designed to evaluate the quantification of the nutrient content of aboveground biomass of teak plantation in a tropical dry deciduous forest of Udaipur, Rajasthan, India. The nutrient contents in the total biomass of teak in the plantation were 165.47 kg/ha N, 20.96 kg/ha P, 35.06 kg/ha K, 49.29 kg/ha Ca, 31.52 kg/ha Mg, 4.27 kg/ha Na, 4.06 kg/ha S and 3.21 kg/ha Cl. In total, 42.93% of the dry matter accounted for crown biomass (leaves, branches, twigs and reproductive parts), which in turn accounts for 60.93% N, 58.63% P, 54.30% K, 51.40% Ca, 62.5% Mg, 53.62% Na, 59.85% S and 60.74% Cl of the aboveground biomass, whereas 57.07% of the dry matter account for trunk biomass (bole bark and bole wood), which in turn accounts for 39.07% N, 41.37% P, 45.70% K, 48.6% Ca, 37.5% Mg, 46.38% Na, 40.15% S and 39.26% Cl.

Fertilization represents a measure, used as exceptional treatment managing forest stands and ecosystems as a whole. It is used since the beginning of the 20^th century worldwide, starting in the Central Europe. The beginnings were on empirical basis, later on, the scientific background was developed profoundly. Several forms and methods, as well as aims are topical at present: - Since the beginning, restoration of degraded sites and amelioration of primarily extreme soils was the aim. In the poorest regions, e.g. in the NE Germany, different means were used to increase site productivity and stability. Also in the Czech countries, amelioration played important role restoring degraded and devastated localities. - To increase site productivity, commercial fertilization was used worldwide, as well as it was applied in all continents with intense forestry practices. It became a part of the "silviculture" sensu stricto in the commercial, industrial forestry. - Supporting the growth and prosperity of forest plantations, on sites of different characters, was a broadly intended target of fertilizers application. - Since the air pollution calamity, fertilization is one of the main counter-treatments for improvement of the situation, lowering and preventing the soil acidification and nutritional degradation. Both direct as well as indirect methods are used. At the direct fertilization, nutrients in the fertilizers increase and improve the nutrient cycles over the degraded or natural level. This causes an increase in the forest ecosystem production as the main aim of such a treatment. In the indirect way, the amelioration material accelerates the bio-cycles by improving biological activities of the soil - liming is the best example of these activities. Nutrients are mobilized by enhanced activity of the soil biota, increasing organic matter mineralization and decay. This also represents the main ecological risk of these activities: the enormous and non-natural organic matter decay. Different types of fertilizer can be used: liquid, firm, powdered, pelletized, based on natural substances such as carbonates or silicate nutrient-rich (basic) rocks. In all cases, the uses of all these treatments have to be based on the detailed ecological analysis of the locality, of the site and of the forest stand. Only in this case, fertilizer effects can be optimized and the risks minimized.

During 2004-2006, another permanent research plot (No. 12) on Pop Ivan Marmarosh Mt. in the Zakarpattya province of Ukraine was renewed, i.e. re-measured and re-analyzed. The plot was originally established in the 30's of the 20^th century. The tree layer is dominated by European beech (Fagus sylvatica L.), with Silver fir (Abies alba Mill.) and Norway spruce (Picea abies [L.] Karst.) as often associated species, and with sycamore maple (Acer pseudoplatanus L.) growing occasionally in small groups. After 70 years, the tree species composition partly changed. Total live timber volume increased from 529.6 to 636.3 m³/ha. Considerable growth was recorded in beech, while the live timber volume of fir, spruce and sycamore maple did not almost change. Total number of trees (> 3 cm in dbh) increased from 737 trees/ha to 760 trees/ha. Number of beech trees increased markedly. On the contrary, fir and spruce showed a significant decrease in tree number. Interesting results emerged from the renewal of the permanent square plot (20 × 20 m), proving that beech is able to persist in the shade for more than 70 years with only minimal increment of both height and diameter.

In conifers and other plants with long reproductive cycles, transformed embryogenic tissues can serve as a convenient source of plant material for the testing of insecticidal or fungicidal transgene efficiency. In this report, transgenic embryogenic tissue was obtained after the transformation of somatic embryos of Norway spruce (Picea abies (L.) Karst.) by Agrobacterium tumefaciens with the gus-intron chimeric gene. The stable integration of transgenes was confirmed by PCR and Southern hybridization. The transformation was successful only in a suitable embryogenic cell line sensitive to Agrobacterium. Out of the nine embryogenic lines tested only one gave transgenic callus.

Light conditions were measured along six transects from 35 m inside of a mixed Norway spruce/Scots pine forest to an adjoining clear-cut in NW-Austria. Photosynthetic photon flux density (PFD) was recorded every minute of the day from 5:00 a.m. to 8:00 p.m. for three weeks in July. PFD decreases exponentially from the clear-cut to the interior of the forest following the gap fraction. Low light intensity classes (< 50 µmol photons m²/s) decrease from the stand towards the open, whereas the clear-cut receives light of higher intensities (> 200 µmol photons m²/s) for most of the day. PFD values assessed during the day were compared with photosynthetic light response curves measured on advanced planting of broadleaf species in the same stand. The high light compensation point of Quercus petraea enables carbon gain in deep shade for about 60% of the day. The other shade tolerant species Fagus sylvatica and Acer pseudoplatanus can perform net photosynthesis at 80% and 90% of the time, respectively. This reduces the possibility of advanced planting of light demanding species to the first few meters of the inner part of the forest edge.

The abundance and species spectrum of cockchafers of the genus Melolontha and characteristics of the tribes in four forest regions of theCzechRepublic was explored. We used light traps, automatic meteorological stations and field investigations to study the course of swarming, species composition, abundance of the respective tribes, sex ratio during swarming and the dependence of swarming on the average daily temperature. Studies will continue in the next years and the objective is to use the results for prognosis of the occurrence of cockchafers and the damages subsequently caused by grubs in forest cultures.

Like in other types of forests the greatest changes in the soil of floodplain forest stands occur during their regeneration. These changes are manifested as changes in the content and dynamics of organic matter in the soil. Research was conducted in oak and ash floodplain forests in the eastern part of Croatia and in southern Moravia in the Czech Republic. The results showed that the type and extent of these changes depended, in addition to environmental factors, also on the technology of forest regeneration. The natural regeneration of oak in floodplain forests of Spačva (eastern Croatia) protects soil from dramatic changes in soil by successive regeneration felling and that it retains the plant cover permanently. The weight of organic matter on the soil surface is increased after regeneration till the period when the effect of thinning becomes evident (about 70 years). In the surface mineral layer of soil the pH value increases after shelterwood felling. Stand regeneration with clear-cutting results in a rapid change in the conditions of surface humus accumulation and decomposition. The process of organic residue accumulation is interrupted in the clearings. In the preparation of soil/site by ploughing, the concentrations of nitrogen and carbon slightly decrease. The management impact depends on the method of site preparation for the establishment of a new stand. The selection of a method of the floodplain forest regeneration (particularly of oak) is markedly dependent on actual ecological conditions and on ecological and historical experience of the given region.

Unit hydrograph is a basic method to show changes in runoff in the watershed. The investigation of runoff changes was carried out in the U Dvou louček watershed situated at the summit part of the Orlické hory Mts., East Bohemia. The waveform ordinates of recession limbs of unit hydrographs obtained using a common approach had to be approximated by the least-squares method. Final hydrographs reflected both drainage treatment and forest stand growth influencing the runoff from the watershed. Both factors increase culmination in synergy and reduce runoff on the recession limb of the hydrograph. We confirmed increased maximum runoff taking up 25-30% of the total runoff time when waterlogged sites were drained. The culmination increased by 0.2-0.8 mm/hour indicates the runoff increased by 2-8 m³/ha/hr.

The afforestation of agricultural lands was carried out under different site and ecological conditions, including lower and medium elevated localities. The present study documents the rapidity of accumulation of surface layers and their characteristics in stands of Scots pine (Pinus sylvestris), Norway spruce (Picea abies), birch (Betula verrucosa) and Douglas fir (Pseudotsuga menziesii) in the territory of the Training Forest Enterprise in Kostelec nad Černými lesy, at the altitude 430 m a.s.l., on the site of nutrient-poor gleyed soils. The plots were compared with the neighbouring continuously forested site covered with old pine-spruce stand and with near-situated arable field. During the first roughly 40 years, considerable changes were documented on the afforested plots. Forest-floor humus layers in the coniferous stands have already been formed, the humus forms being more favourable compared with the old forest site. Acidification and loss of nutrients run in the upper mineral horizons. These processes were also responsible for the less favourable character of the forest soil in the old stand. Birch showed minor shifts of soil properties in the mineral horizon compared to the conifers; the surface humus accumulation was not observed there yet. The lowest degradation among conifers was shown in Douglas fir, intensively taking up deficient nutrients on the other hand.

The differences between oak lepidopteran communities were studied in Slovakia in 1993 and 1994. Sampling was undertaken between April and October on 3 oak species (Quercus robur, Q. petraea, Q. rubra). Biological traits of larvae were examined in order to explain differences in seasonal guilds among oaks. Communities varied in structure and abundance. Species richness in four seasonal guilds (flush, late spring, summer and autumn feeders) had a similar pattern on each of the studied oak species. The guild of flush feeders had the richest species assemblage, followed by the late spring feeder guild and both guilds were significantly richer than the summer feeder guild and autumn feeder guild.

Humus forms dynamics and characteristics of different forest sites were studied in the area of Smrčina Mt. in the Šumava National Park territory. The study was performed in vital Norway spruce forest, dead Norway spruce forest (bark beetle Ips typographus infestation) and on a clear-cut area (site conditions were comparable for all three plots). The amount of surface organic matter was not affected by forest decline or by clear-cut (95.5 t/ha, 73.1 t/ha and 100.2 t/ha, respectively), pH being comparable (between 2.3 and 3.2 pH KCl). A slight favourable effect of grass litter on pH increase was obvious; higher leaching of bases occurred in lower horizons. Nitrogen losses were detected from the L + F horizons, falling from 1.93-1.83% (living stand) to 1.73-1.83% (clear-cut area). Higher ammonia production was documented in substrates (F and H horizons) from the living stand (from 263 and 103 mg/kg before incubation to 610 and 248 mg/kg after incubation - nitrogen content in ammonia form), and higher nitrification rates (nitrogen content in nitrate form) were recorded on the clear-cut area (103 and 80 mg/kg to 153 and 87 mg/kg) and especially in the dead stand (160 and 93 mg/kg to 216 and 139 mg/kg). Respective values for the living stand increased from 52 and 61 mg/kg to 119 and 84 mg/kg. Respiration activity, both potential and basic, was more balanced, indicating more intensive dynamics in the case of dead stand and clear-cut area.

Forest soil acidification and depletion of nutrient cations have been reported for several forested regions in North America, predominantly in the eastern United States, including the northeast and in the central Appalachians, but also in parts of southeastern Canada and the southern U.S. Continuing regional inputs of nitrogen and sulfur are of concern because of leaching of base cations, increased availability of soil Al, and the accumulation and ultimate transmission of acidity from forest soils to streams. Losses of calcium from forest soils and forested watersheds have now been documented as a sensitive early indicator and a functionally significant response to acid deposition for a wide range of forest soils in North America. For red spruce, a clear link has been established between acidic deposition, alterations in calcium and aluminum supplies and increased sensitivity to winter injury. Cation depletion appears to contribute to sugar maple decline on some soils, specifically the high mortality rates observed in northern Pennsylvania over the last decade. While responses to liming have not been systematically examined in North America, in a study in Pennsylvania, restoring basic cations through liming increased basal area growth of sugar maple and levels of calcium and magnesium in soil and foliage. In the San Bernardino Mountains in southern California near the west coast, the pH of the A horizon has declined by at least 2 pH units (to pH 4.0-4.3) over the past 30 years, with no detrimental effects on bole growth; presumably, because of the Mediterranean climate, base cation pools are still high and not limiting for plant growth.

The impact of blue spruce (Picea pungens) and reed Calamagrostis villosa) cover on quantity and quality of upper soil layers was investigated. The research was conducted in the Jizerské hory Mts., Czech Republic (altitude 880 m, acidic spruce forest site type - 8K). Mean weight of dry matter of holorganic horizons was similar under both variants. Totally, there were accumulated 153 t/ha of dry matter of humus horizons in blue spruce and 174 t/ha in reed. Soil pH (KCl) varied from 3.7 to 3.2 under blue spruce stand and from 3.6 to 3.3 under reed. The differences of concentrations of nutrients (P, K, Ca, Mg) were not found significant either. Only L horizon showed significant differences: there were higher values of cation exchangeable capacity (T) and higher content of exchangeable bases (S) under reed. We found very similar forest-floor humus properties under both species. Therefore we can not state worsening of the soil conditions under blue spruce compared to areas covered with tested forest weed species.

The objectives of this study are to determine the relationship between crown characteristics and the radial increment of beech (Fagus sylvatica L.) and to specify the characteristics of beech trees with the radial increment above the average in the Świętokrzyski National Park. The following relationships have been found: the radial increment of beech increases as the degree of the freedom of the light part of the crown from neighbouring trees increases, and the increase in the relative crown length causes a significant increase in the radial increment. Most of the best growing beech trees are characterized by the light part of the crown confined in an area of up to about 55%, and the relative crown length spanning the range of 55% (trees 61 to 80 years of age at b.h.) to 76% (trees 21 to 40 years of age at b.h).

Multiaged silviculture is highly variable across North America but a commonality is the ties to the negative exponential diameter distribution to guide stocking control. These methods have evolved in several regions to include alternative stand structures and new stocking control tools are being developed. A trend in these new developments is integrating disturbance regimes and their effects on stand structure. The result, in some cases, is a movement towards longer cutting cycles and more flexible guidelines for stand structure.

The paper deals with the use of European beech in the reconstruction of substitute species stands and in the regeneration of existing spruce stands in the air-polluted region of the north-eastern Krušné hory Mts. (air-pollution damage zones A, B, forest altitudinal vegetation zones 6 and 7, acidophilic sites). Twenty stand situations were analyzed during the study. The study objective was to compare the growth of European beech plantations in the Krušné hory Mts. with the growth of plantations of the same age in similar sites in the unpolluted region of the Bohemian-Moravian Upland (air-pollution damage zones C, D, forest altitudinal vegetation zone 6, acidophilic site). Each plant was assessed for eight growth and visually classified parameters and traits. Results of the survey showed that in the existing air-pollution and climatic situation, it is possible to switch to normal (shelterwood) beech management of higher elevations in the north-eastern Krušné hory Mts. The stands of substitute species and the current stands of Norway spruce may effectively eliminate injuries caused by late frost.

The author analyzes the changes in the tree species composition of Dentario glandulosae-Fagetum Klika 1927 em. Mat. 1964 in the mountain stands of Bieszczady National Park in 1993-2003. The analysis takes into account the changes over a ten-year period in the number and volume structure of each tree species in each stand layer: young natural regeneration, undergrowth, and mature stand. Additionally, after comparing the results with the natural Carpathian forests' structure, the adaptation level of the present tree species composition to the current climate and soil conditions, as well as probable directions of future changes have been assessed. A ten-year period is too short to find significant changes in stand species structure but it is possible to see some trends: beech share in stands is increasing and fir is decreasing.

The mycological conditions on study plots established in forests growing on former agricultural farm lands were studied. In young spruce stand (8-10 years) reduced and unstable spectrum of macromycetes was found. After approximately 50 years of forest growth the situation became stable and spectrum of macromycetes together with development of mycorrhizal status were similar to a situation found in stands on forest soils. Slightly increased occurrence of saproparasitic species of fungi (e.g. Heterobasidion annosum at others) was observed in older growths.

The study is a follow-up of the production potential of Douglas fir in mesotrophic sites of the Křtiny Training Forest Enterprise (TFE) (Journal of Forest Science, No. 7, 2008). Production parameters (height, dbh, volume) of Douglas fir are also evaluated, but in acid sites of the Hůrky Training Forest District, Secondary Forestry School in Písek in mature stands. In total, 17 mixed stands with the proportion of Douglas fir aged 88 to 121 years were assessed. Comparing 10 Douglas fir trees with 10 Norway spruce, Scots pine or European larch trees of the largest volume, higher and generally markedly higher production potential of the introduced Douglas fir was always found in all assessed stands. Groups where the volume of Douglas fir trees was two to three times higher than the volume of spruce, pine or larch were not an exception. For example, in stand 22B10, the mean volume of the 10 largest Douglas fir trees was 6.30 m³ but the volume of spruce trees was only 1.93 m³ and the volume of larch trees 2.25 m³. Differences between the mensurational parameters of Douglas fir and spruce (or larch) assessed by the ANOVA test were statistically highly significant. At present (based on annual ring analyses), the volume increment of particular Douglas fir trees ranges at level of 0.06 to 0.10 m³/year (i.e. about 0.6 m³ to 1.0 m³ per 10 years) in mature stands.

The diversity of arbuscular mycorrhizal (AM) fungi of Acacia catechu Willd. was studied. Dominant AM spores, the bacterium Rhizobium sp. along with the fungus Trichoderma viride were isolated from the rhizosphere of A. catechu and mass-produced in laboratory. The co-inoculation effect of Glomus mosseae, Glomus fasciculatum, mixed AM (Glomus spp. [except G. mosseae, G. fasciculatum] with Acaulospora spp., Sclerocystis spp. and Gigaspora spp.), Rhizobium sp. and Trichoderma viride was studied as exerted on the growth of A. catechu seedlings. All inoculated seedlings showed improved seedling growth compared to the control. Inoculated seedlings had a pronounced effect on all growth parameters such as height, fresh and dry weight of roots and shoots, AM spore count, per cent mycorrhizal colonization in roots and root nodule number in comparison with uninoculated seedlings. Phosphorus uptake was also higher in inoculated seedlings than in the control. This study provides a good scope for commercially utilizing the efficient strains of AM fungi for beneficial effects with other beneficial rhizosphere microflora in the primary establishment of slow growing seedlings ensuring better survival and improved growth.

This paper presents detailed data on the biomass and element pools of six sample trees in the catchments of Plešné andČertovoLakes. Diameters and heights of the sample trees ranged from 28.0 to 63.7 cm and from 14.1 to 38.7 m. The age of the sample trees ranged from 84 to 177 years. Total biomass of the sample trees was in the range of 239.4 kg to 2,932.3 kg. Variation of total biomass between the sample trees was a consequence of the tree biometric data (height and dbh) and age differences. The proportion of stem wood and bark ranged from 63.5 to 69.5%, and from 4.6 to 7.2%, respectively. The proportion of foliage and fine branches ranged from 4.3 to 8.4%, and from 0.7 to 1.9%, respectively. The proportion of branch wood and bark ranged from 2.2 to 6.5%, and from 0.8 to 2.2%, respectively. Mean concentrations of C in different tree components were quite similar. Except C and compared to the other elements, N had the highest mean concentrations in tree components in all cases. Concentrations of P, Ca, Mg, and K showed similar patterns. Generally the highest concentrations of these elements were found in foliage, fine branches, fine roots and bark of stem and branches. Fe, Na, Al and Mn showed the lowest mean concentrations in tree components for all the analyzed elements. The total element pools per tree were highly variable because of the differences in total biomass between the individual trees. Generally, stem wood and bark, foliage, and roots contained the highest proportion of the elements. But there were differences between individual elements. Concerning the important nutrients, while the highest proportion of Ca and Mg was contained in stem wood and bark, the highest proportion of P was contained in foliage. The foliage contained a relatively high proportion of P and K, but a relatively low proportion of Ca and Mg.

Common ways of nursery cultivation and sorting the planting material of mountain provenances of Norway spruce (Picea abies [L.] Karst.) are connected with the risk of undesirable narrowing of the genetic spectrum of populations. Investigations in spruce plantations established by different planting materials found out very good growth (total height is 125 cm 9 years after outplanting) and health status of these slowly growing seedlings planted in extreme mountain conditions. In order to prevent the genetic spectrum narrowing, we recommend to cultivate all seedlings including smaller outsorted (commonly culled) ones. The smallest seedlings can be grown one year longer and subsequently planted out in the same locality as the remaining planting material of the same seed lot.

The formation, size distribution and percentage of gaps in two virgin deciduous forests are presented in two case studies. Gaps are defined as openings in the canopy above 2/3 of stand height. These gaps comprise 16% of the forest area in Havešová Reserve and 14.6% of the forest area in Kyjov Reserve. The estimated turnover time is 220 years. More than half the gaps were caused by the death of one tree, and 80% of the gaps were due to the death of up to 3 trees. The largest gap in Havešová Reserve was 0.40 ha, resulting from the death of 56 trees over the last 40 years. The area of the largest gap in Kyjov Reserve was 0.44 ha. It was caused by the death of 80 trees over the last 40 years. Such large gaps are scarce. 85% of the gaps are smaller than 250 m². A correction of the bias towards the over-abundance of large gaps by line-transect sampling was made by estimating the percentage area of gaps of different size from the percentage length along the transects. In Havešová an attempt was made to date the death of trees that were still visible in the gaps. 1/5 of the trees initiated gaps by their death, while 4/5 of the trees extended gaps. While uprooted trees dominate in Havešová, breakage is most common in Kyjov.

The paper characterizes the natural conditions and current state of floodplain forests in the area of Litovelské Pomoraví and proposes the protective management of the area in accordance with the European Natura 2000 system. The paper describes the geographical location and the natural conditions of the area of interest (climate, geology, geomorphology, hydrology and flood regime, soils, and vegetation). Six groups of geobiocene types were identified, classified and described in detail. Assessment of the ecological stability of the forest stand was carried out using biogeographical differentiation of the landscape and the outline of the forest ecosystem management is drawn based on the differentiation of the protected landscape area into zones with various levels of protection.

Wild cherry is one of the noble hardwood species that increase the biodiversity of our forests and at the same time it could increase the income for forest owners. The preconditions for achieving these goals are the high quality of stem and appropriate silvicultural management. This means that wild cherry should occupy the main crown layer in the stand. The height/frequency diagram depicts two groups of wild cherry trees in the stand belonging to dominant/codominant and suppressed tree classes. Height periodic increment (measured between the years 2001 and 2007) is significantly (p < 0.01) different in these two groups confirming that there is no transition chance for the trees from the suppressed group to become a part of the main crown layer and play the role of future crop tree. The same is true of the diameter/frequency diagram which also has a two-peak shape remaining also at the end of the surveyed period. Our result suggests that silvicultural care should be focused only on trees belonging to future crop trees.

The aim of the study is to evaluate the role of the Grand fir (Abies grandis [Dougl. ex D. Don] Lindl.) as a soil-improving species in the area of the University Training Forest in Kostelec nad Černými lesy, Jevany district. The state of humus forms in the stand part with Grand fir was compared with the mature Norway spruce (Picea abies [L.] Karst.) without regeneration, with young beech (Fagus sylvatica L.), Norway spruce (Picea abies [L.] Karst.) and oak (Quercus spp. L.) stands (all of pole stage). The site is characterized as 4P1 - acid oak-fir site with Luzula pilosa, the geological bedrock is formed of cretaceous sandstone with loess overlays, the soils are Luvisols, the terrain is flat at the altitude of 420-440 m a.s.l. The humus form samples (L, F, H, Ah horizons) were taken in 4 replications, quantitatively for the holorganic layers. The dry mass amount and total nutrient contents were analyzed for holorganic horizons, the basic pedochemical characteristics (pH, soil adsorption complex characteristics, exchangeable acidity and exchangeable nutrients) were determined for all horizons. The results confirmed marked and positive effects of the Grand fir litter on the surface layer characteristics. This tree species supports the litter of good composition, transforming easily and forming humus forms of higher quality compared to coniferous as well as studied broadleaved species.

The spruce-fir-beech dominated forest stands in Litschau in the Austrian part of the Bohemian Massif were converted by former forest management practices into pure Norway spruce stands and are now discussed to be reconverted into the potential natural vegetation type. The targeted potential natural vegetation type is usually defined by experts in vegetation sciences. Because meanwhile individual-tree growth simulators are a well acknowledged tool for predicting future forest stand development, in this study we investigate if PROGNAUS can also be used to predict the redevelopment of managed forest ecosystems into natural forest ecosystems regarding species composition. The development of 23 stands in Litschau has been simulated over 1,000 years under the "no-management" option. Generally, the simulated species distribution agrees quite well with the expectations of the potential natural vegetation type. However, the predicted amounts of silver fir and maple species are lower than expected, which probably is due to browsing and management effects represented in the parameterization data for PROGNAUS.