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Results 301 to 330 of 525:

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.

Influence of a planting hole application of dolomitic limestone powder and basalt grit on the growth of Carpathian birch (Betula carpatica W. et K.) and soil chemistry in the air-polluted Jizerské hory Mts.

I. Kuneš, V. Balcar, D. Zahradník

J. For. Sci., 2007, 53(11):505-515 | DOI: 10.17221/2023-JFS

The objective of the study was to evaluate the growth potential of Carpathian birch (Betula carpatica W. et K.) at an environmentally harsh mountain site and a response of this species to altered soil chemistry after dolomitic limestone and basalt grit applications. The Carpathian birch proved to be a suitable species for the replanting of extreme acidic mountain sites. This birch shows a low mortality rate, grows well in the clear-felled patches and soon forms a cover which is necessary for the reintroducing of more sensitive tree species. The application of dolomitic limestone and basalt grit resulted in the slower growth of Carpathian birch plantations. Liming raised soil reaction, sum of exchangeable bases, base saturation, cation exchange capacity and reduced exchangeable Al content. On the other hand, liming decreased an amount of oxidizable soil organic matter and negatively affected soil N, exchangeable P and K. Basalt grit increased exchangeable P and K contents and raised soil reaction, however only slightly. The influence of basalt grit on the sum of exchangeable bases, base saturation and cation exchange capacity was also less pronounced compared to liming. Basalt grit elevated the proportion of exchangeable aluminium and reduced the content of soil N.

Growth and development of silver fir (Abies alba Mill.) regeneration and restoration of the species in the Karkonosze Mountains

D. Dobrowolska

J. For. Sci., 2008, 54(9):398-408 | DOI: 10.17221/29/2008-JFS

The main task of the study was to investigate the growth conditions of silver fir natural regeneration in the Karkonosze Mts. (Poland). The paper examines the quantity and quality of light reaching the forest floor in stands of different canopies. The aim of the study was also to define the optimal site conditions for silver fir planting under stand canopy. Data on the natural regeneration and stand structure of each investigated stand were collected on circular plots in a grid of 15 × 15 m in 1999 and 2000. Biometric measurements of fir plants planted under various stand canopies were done three times (May 1999, autumn 2000 and 2001). It was found that the fir was not a dominant tree in all size classes from seedlings to saplings. Seedlings (both phases) of spruce, beech, sycamore and rowan occurred in all studied stands. The optimal conditions for fir development were found under larch canopy. That was demonstrated by the highest increment of height, diameter and offshoots. The worst conditions for fir growth were under beech and spruce canopy, which was indicated by the lowest diameter and height. The highest PAR was recorded under pine canopy, whereas the lowest one under beech canopy. Beech stand induced a lower R:FR ratio than the other tree species both on sunny and cloudy days. The highest R:FR ratio was found under the canopy of larch and pine stands.

Analysis of the aerial application of fertilizer and dolomitic limestone

M. Bošeľa, V. Šebeň

J. For. Sci., 2010, 56(2):47-57 | DOI: 10.17221/29/2009-JFS

The paper evaluates the quality of revitalization treatments (fertilization and liming) carried out in selected areas within Forests of the Slovakia (state enterprise) during the year 2008. Revitalization treatments were carried out in declining Norway spruce forest stands in different site conditions. Full-scale aerial technology (helicopter and crop duster) was applied. The aim of the study was to find out the total amount and its variability of both fertilizers and dolomitic limestone after their application. The analyses revealed significant differences between the amount of fertilizer and dolomitic limestone which was applied to selected areas and the required amount (norm). As for fertilization, the largest difference was found in magnesium (Mg) on Šaling area (the amount of magnesium reached only 7% ± 0.5 of the norm) and in zinc (Zn) on Ľadová area (only 8% ± 1 of the norm). The required amount according to the norm was approximately met in boron (B) on Ľadová area (65% ± 10 of the norm). Yet, a significantly lower amount of fertilizers than the required one was revealed on all selected areas. After the application of dolomitic limestone to Liptovská Teplička area the significantly lower amount than the required one was found out (72% ± 12 of the norm). On the other hand, the significantly higher amount of dolomitic limestone than the required one was determined on Smolník area (143% ± 27 of the norm). Results also show the huge spatial variability of both fertilizers and dolomitic limestone on all selected areas (from 40% up to 100% between collecting places, and up to almost 170% between collectors within the collecting places). Such high variability of applied fertilizers and dolomitic limestone and the lower total amount than the required one will influence the effect of revitalization treatments.

Evaluation of the growth and health status of selected clone mixtures in comparison with ordinary planting stock

J. Leugner, A. Jurásek, J. Martincová

J. For. Sci., 2010, 56(7):314-322 | DOI: 10.17221/92/2009-JFS

The present paper compares the growth of parent trees and potentially stress-tolerant mixtures of clones of Norway spruce (Picea abies [L.] Karst.) progenies coming from a specific locality near the Černá hora peat bog in the Krkonoše Mts. Growth was studied in generative ortet plantations in Trutnov locality and in a mountain ortet plantation Lesní bouda, in the 1st generation clone plantation Benecko and in the 2nd generation clone plantation in the Černohorská rašelina locality. In the latter locality chlorophyll fluorescence and water losses during controlled desiccation were also measured in selected clones compared to control (generatively propagated) spruces. Partial data acquired until now prove the good growth dynamics and physiological state of some clones in extreme climatic conditions indicating that cuttings were taken from vital parent trees growing in exposed mountain localities. Growth relations among the clones were identical in all evaluated localities. The growth of the 2nd generation clone plantation has been markedly influenced by plantation and specific site conditions until now. The mutual interaction of clone growth and site conditions can change in time and therefore the study of clone plantations will continue in the years to come.

Different technologies of floodplain forest regeneration from the aspect of soil changes

N. Pernar, E. Klimo, S. Matić, D. Bakšić, H. Lorencová

J. For. Sci., 2009, 55(8):357-367 | DOI: 10.17221/8/2009-JFS

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.

Production potential and ecological stability of mixed forest stands in uplands - V. A mixed spruce/beech stand on a nutrient-rich site of the Křtiny Training Forest Enterprise

P. Kantor, V. Hurt

J. For. Sci., 2003, 49(11):502-514 | DOI: 10.17221/4793-JFS

The study is already the 5th account on the production potential and stability of mixed forest stands in uplands. A spruce/beech stand established in the mid-30s of the 20thcentury 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.

Pinus pumila growth at different altitudes in the Svyatoi Nos Peninsula (Russia)

R. Gebauer, D. Volařík, T. Funda, I. Fundová, A. Kohutka, V. Klapetek, M. Martinková, O. A. Anenkhonov, A. Razuvaev

J. For. Sci., 2010, 56(3):101-111 | DOI: 10.17221/60/2009-JFS

Detailed research is necessary to better understand ecological adaptations of Pinus pumila (Pall.) Regel as a species, whose biological properties are vital for its survival. In the Svyatoi Nos Peninsula, three sites differing in altitude were selected. At all sites the growth form of P. pumila was determined. At the high and medium sites, the following parameters were measured: linear increment on terminal branches, leaf mass per area and the content of nitrogen per unit leaf area. Anatomical studies were carried out on shoots and four needle-year classes. It was found that needles were longer and narrower at the medium site when compared to the high site. Leaf mass per area was higher and a substantial increase in older needles occurred at the high site. Nitrogen content per unit leaf area served as an indicator of assimilation capacity and was higher at the high site. We can conclude that P. pumila has xeromorphic needles, higher assimilation capacity, better protection ability against pathogens and slower growth rate of terminal branches at the high site. Important is also a significant increment of the growth rate of terminal branches at the high site in recent years. Therefore, data obtained from sites at the upper forest limit are valuable in assessing the climate changes and are useful for the forest management practice in mountain areas.

Productivity and cost of farm tractor skidding

N. Gilanipoor, A. Najafi, S.M. Heshmat Alvaezin

J. For. Sci., 2012, 58(1):21-26 | DOI: 10.17221/4804-JFS

In this study, productivity rate and operation cost of farm tractor were evaluated in a mountainous natural forest. Data for the study came from a detailed time study in the Research and Educational Forest of Tarbiat Modares University (REFTMU) and was used to develop a multiple linear regression model to predict the skidding cycle time. The results showed that effective independent variables of skidding time were skidding distance and slope of skid trail (P = 0.01). Average productivity rate ranged from 2.43 to 2.60 m2.h-1. Total time and effective time, respectively. Total cost of the system was 10.24 USD.h-1 whereas 4.58% of the cost of skidding resulted from personal delay. The cost and productivity resulting from this study emphasized the importance for foresters to consider a farm tractor when designing skidding operations in young stands or prescribing a combination of two machines in mature stands.

The use of hyperspectral remote sensing for mapping the age composition of forest stands

O. Skoupý, L. Zejdová, J. Hanuš

J. For. Sci., 2012, 58(6):287-297 | DOI: 10.17221/86/2011-JFS

The paper deals with the issue of mapping the age composition of stand groups using hyperspectral imagery acquired by the AISA Eagle VNIR sensor in the Bílý Kříž locality in the Moravian-Silesian Beskids Mts. An object-oriented approach was employed through segmentation and subsequent classification by means of Nearest Neighbour (NN) algorithm in the environment of eCognition Developer 8 and artificial neural network (ANN) classification provided by ENVI 4.7 software. Because of the dominant occurrence of Norway spruce (Picea abies [L.] Karst.) monocultures in the studied locality the work focuses primarily on the distinguishability of two selected age classes of Norway spruce (10-20 years and 70-80 years). It studies possibilities of a more detailed age estimation of stand groups aged from 10 to 80 years based on the classification into the boundary classes, which shows similarity to dithering based on random algorithm. Comparison with the outline map of the Forest Management Plan shows a correlation (r2 = 0.83) between the spectral characteristics of Norway spruce stands and their age composition.

Monitoring of defoliation in forest stands of the Czech Republic and its comparison with results of defoliation monitoring in other European countries

P. Fabiánek, K. Hellebrandová, M. Čapek

J. For. Sci., 2012, 58(5):193-202 | DOI: 10.17221/84/2011-JFS

As a part of International Cooperative Programme on Assessment and Monitoring of Air Pollution Effect on Forests (ICP Forests), defoliation of forest stands has been assessed in the Czech Republic since 1986. Defoliation is one of the principal parameters reflecting the health of forest stands that is assessed on monitoring plots within this programme. Monitoring plots are distributed evenly according to woodiness of the area in a regular schematic network all over the Czech Republic. Even though there has been a long-term reduction of air pollution in most European countries, forest ecosystems reflect these changes with some delay. In the Czech Republic the trend of total defoliation of coniferous and deciduous forest stands has been increasing very moderately in the last 10 years. This trend appears to be partially analogous with some neighbouring countries. Compared to the whole of Europe the trend of defoliation of broadleaves is very similar, but differences have occurred in conifers in the last 10 years. There are significant differences in defoliation levels among the particular countries; in this comparison the Czech Republic is classified as one of the worst. Differences in these levels are very evident especially among the neighbouring countries. To partly eliminate these differences, regular international calibration courses are organized.

Index of volume 58Index

editors

J. For. Sci., 2012, 58(12):I-IV | DOI: 10.17221/6477-JFS

Molecular markers: their use in tree improvement

R. Mahajan, P. Gupta

J. For. Sci., 2012, 58(3):137-144 | DOI: 10.17221/5579-JFS

Earlier breeders used phenotypic selection based on morphological characteristics to improve tree varieties. These selections often take many cycles of breeding and backcrossing in order to place desired characteristics. But today the knowledge has paved the way for a much deeper understanding of the mechanics of cell biology and the hereditary process itself. Breeders are presented with numerous possibilities of altering the behaviour of existing varieties. Linkage between molecular markers can be translated to genetic linkage maps, which have become an important tool in plant genetics. They may choose to use marker-assisted approaches in order to facilitate the selection of favourable combinations of genes that occur naturally within a tree species.

Evaluating productivity, cost, chip quality and biomass recovery for a mobile chipper in Australian roadside chipping operations

M.R. Ghaffariyan, J. Sessions, M. Brown

J. For. Sci., 2012, 58(12):530-535 | DOI: 10.17221/51/2012-JFS

The Bruks mobile chipper was tested for chipping extracted non-merchantable stemwood at the roadside in Pine plantation in Victoria. The elemental time study method was used to evaluate the system productivity. The productivity, cost, biomass yield, remaining slash, chip quality (size classification and energy content), and fuel and energy consumption were analysed. Chipping extracted small logs at the roadside yielded a productivity of 43.88 GMt.PMH0-1 (19.4 BDT.PMH0-1). The average cost was about 16.96 USD.GMt-1 (38.36 USD.BDT-1).

Structure of the montane taiga forests of West Khentii, Northern Mongolia

M. Mühlenberg, J. Appelfelder, H. Hoffmann, E. Ayush, K.J. Wilson

J. For. Sci., 2012, 58(2):45-56 | DOI: 10.17221/97/2010-JFS

Studies were undertaken to investigate the composition, structure and diversity of four different types of North Mongolian montane forest near the southern border of the taiga. These forest types, classified as willow-poplar, larch-birch, spruce-fir and Siberian-pine forests, were found to be significantly different with respect to the elevational gradient. In the study area, two fire regimes could be distinguished at lower and drier elevations, frequent surface fires resulted in less diverse forests comprising coniferous species, which in their adult form were found to be fire-resistant, burn-colonizing and light-demanding deciduous tree species. In contrast, the forests colonizing the moist, higher elevations and shaded slopes had a higher diversity of tree species with greater basal area, higher proportion of deadwood, and more regenerating trees; here the coniferous shade trees experienced infrequent but destructive treetop fires. Overall, our results showed that the four forest types differed in composition according to the tree species, diameter and height classes.

Evaluation of full tree skidding by HSM-904 skidder in patch cutting of aspen plantation in Northern Iran

R. Mousavi, M. Nikooy, A. E. Nezhad, M. Ershadfar

J. For. Sci., 2012, 58(2):79-87 | DOI: 10.17221/78/2011-JFS

This paper presents research results of the performance of HSM-904 grapple skidder using a full tree harvesting method in a non-native aspen Populus deltoides plantation in even terrain conditions in Shafaroud, Northern Iran. Patch cutting as a silvicultural method was used in the plantation (2,000 ha). To evaluate the newly introduced machine to a ground skidding system in the aspen plantation and the possibility to increase the production rate, an empirical time study was conducted. The elements of the skidding work phase were identified and 58 cycles were recorded for the study. The models for effective time consumption, total productivity and work phase models are calculated. The average load per cycle was 2.2 m3, the average one-way skidding distance was 253 m. The average travel speed of unloaded skidder was 5.53 km.h-1 and the average speed of loaded skidder was lower than the speed of the unloaded one by 2.94 km.h-1. The average output in the study was 7.1 m3 per effective hour and the unit cost was 13.9 USD.m-3.

Toward the rational use of forest biomass: Lithuanian case study

I. Varnagiryté-Kabašinskiené

J. For. Sci., 2012, 58(10):465-471 | DOI: 10.17221/10/2012-JFS

This paper contains the information about some principles of sustainable forestry which are still relevant in the world. In 2002, Lithuania started research on the nutrient balance in forest ecosystems when the forest fuel is harvested. The consequences of the intensive forest fuel harvesting on the forest ecosystem were analysed. At the same time, the experiment on the compensatory wood ash fertilizing was established in Lithuania. After the initial calculations, having the experimental data, the Ministry of Environment of the Republic of Lithuania has initiated the preparation of the Recommendations for compensating wood ash fertilization in the forests. This review briefly systematizes and analyses the main results of the related research and some ideas for the future studies are also presented.

Restoration of forest soils on reforested abandoned agricultural lands

V.V. Podrázský, I. Ulbrichová

J. For. Sci., 2004, 50(6):249-255 | DOI: 10.17221/4622-JFS

Restoration of forest soil character after the change of agricultural land use has not been studied yet despite the large areas reforested since the late 40ies of the last century. This process takes place throughout Europe to an increasing extent at present. The reformation of forest soils was studied in the area of Český Rudolec town: Natural Forest Area 16 - Czech-Moravian Uplands, altitude 600-630 m a.s.l., bedrock is built of granites and gneisses, soil type is Cambisol, forest site type 5K1. The process of restoration of a new humus form was analysed in plantations of American red oak (Quercus rubra), Swedish birch (Betula pendula), European larch (Larix europea) and Norway spruce (Picea abies), the site was homogeneous. The particular tree species accumulated 12.81, 13.81, 46.57 and 44.76 t/ha of surface organic matter during the last 30-40 years, these values are typical of forest sites at lower and middle altitudes and corresponding tree species composition. The effect of broadleaved species and conifers was markedly different, in the first case pH in KCl ranged 3.8-3.9 (mineral soil) and 3.5-5.2 (holorganic horizons), being 3.5-3.8 (mineral soil) and 3.1-5.1 (holorganic layers) for the conifers. Visible effects of the particular tree species were also evident in the soil adsorption complex and in the contents of plant available and total nutrients. The results can be summarised and generalised: - the forest soil character is reformed at lower and middle altitudes in a relatively short time from the aspect of surface humus accumulation and basic soil chemistry (30-40 years), - birch exhibited the best revitalisation effect among the studied species, - American red oak and Norway spruce humus accumulation potentials were different although the soil chemistry was comparable, - Norway spruce did not show a remarkable degradation effect until now, - on the contrary, European larch appeared as a site degrading species.

Impact of Scots pine admixture in European beech stand on dissolved organic carbon and nitrogen leaching from organic and humic horizons of Dystric Arenosols in Northern Poland

J. Jonczak, A. Parzych

J. For. Sci., 2012, 58(6):278-286 | DOI: 10.17221/7/2012-JFS

The effect of Scots pine admixture in European beech stand on the leaching of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), nitrate nitrogen (NO3-N) and ammonium nitrogen (NH4-N) from organic and humic horizons of Dystric Arenosols was studied in northern Poland in 2008-2009. Three zero-tension lysimeters under organic and humic horizons were installed in pure beech and mixed pine-beech stands. Water samples were collected after each rainfall, measured volumetrically, filtered and analysed. In each sample pH and concentrations of DOC, DON, NH4-N and NO3-N were analysed. Stronger acidification of leachates was observed in mixed stand compared to pure beech. About twice higher concentration of DOC and its fluxes per unit area were determined in mixed stand. The fluxes of DOC from unit mass of soil were less varied. In general, lower concentrations of DON, NH4-N and NO3-N as well as fluxes of the components (calculated in mg.kg-1DM.year-1 and mg.m-2.year-1) were observed in mixed stand.

Current use of European beech (Fagus sylvatica L.) for artificial regeneration of forests in the air-polluted areas

P. Hobza, O. Mauer, M. Pop

J. For. Sci., 2008, 54(4):139-149 | DOI: 10.17221/788-JFS

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.

Structural and compositional responses to timber harvesting for an old-growth forest on Changbai Mountain, China - Short Communication

H. Gu, L. Dai

J. For. Sci., 2008, 54(6):281-286 | DOI: 10.17221/20/2008-JFS

Broadleaved-Korean pine (Pinus koraiensis) mixed forest is a dominant native vegetation type in the eastern Eurasian Continent. We intended to examine the implications of high-intensity timber harvesting (ca 70% of stand volume) for the sustainable management of a mixed forest ecosystem. We measured trees at three sites: control without cutting, older-cut site cut in 1987 and newer-cut site (cutting in 1997). There were significant differences in structure and composition between these three sites in 2003. There were 4,441 trees of 14 species with basal area 56 m2 at control plot, 6,314 trees of 16 species with basal area 9 m2 at newer-cut site and 8,438 trees of 21 species with basal area 31 m2 at older-cut site (all on the area of 1 ha). The high-intensity timber harvesting system helped promote natural regeneration and the growth of small trees but it also allowed light-demanding tree species to invade into the forest. Dominant position and suitable diameter distribution of economically important species (Pinus koraiensis and Tilia amurensis) were maintained across the three sites. The existing timber harvesting appears to consider short-term economic values to a larger extent than long-term ecological values. To manage the broadleaved-Korean pine mixed forest for both timber production and biodiversity conservation, timber-harvesting intensity must be lowered.

The effect of liming on the mineral nutrition of the mountain Norway spruce (Picea abies L.) forest

J. Kulhavý, I. Marková, I. Drápelová, S. Truparová

J. For. Sci., 2009, 55(1):1-8 | DOI: 10.17221/96/2008-JFS

Mineral nutrition represents the uptake, transport, metabolism and utilization of nutrients by the forest stand. These processes influence all physiological functions of trees. A specific minimum amount of all nutrients is necessary for the healthy development and growth of forest trees. The uptake of nutrients is influenced not only by natural conditions but also by anthropogenic activities. During the period of 2000-2005 the mineral nutrition of mountain Norway spruce stands was studied at the study site Bílý Kříž (Moravian-Silesian Beskids Mts., Czech Republic). Research was carried out in a spruce stand that was limed in the past years (in 1983, 1985 and 1987) and in a spruce stand that was not limed in order to compare the liming effect on the mineral nutrition of spruce stands. A positive liming effect was detected in the calcium, magnesium and phosphorus nutrition because their contents in current needles were higher on the limed plots. No liming effect was determined in the nitrogen, potassium and microelement (Fe, Mn, Cu, Zn, Al) content in current needles. Sufficient nutrition of spruce stands only with calcium was recorded on all studied plots.

Humus conditions of stands with different proportion of Douglas fir in the Hůrky Training Forest District and Křtiny Training Forest Enterprise

L. Menšík, J. Kulhavý, P. Kantor, M. Remeš

J. For. Sci., 2009, 55(8):345-356 | DOI: 10.17221/9/2009-JFS

The paper presented evaluates reserves and chemical composition of forest floor of three stands of Douglas fir, spruce and spruce with beech at acid sites (3K) in the Hůrky Training Forest District (TFD) and at a meso-trophic site (4H) in the Křtiny Training Forest Enterprise (TFE). The aim of the study was to evaluate: (i) reserves of forest floor, (ii) soil reaction, (iii) total content of carbon and nitrogen for the forest floor layers, iv) C/N ratio, and (v) the content of dissolved organic carbon (DOC). The lowest reserve occurs in the Douglas fir stand at a mesotrophic site (25.0 t/ha), the highest accumulation occurs in the spruce stand and in the spruce/beech stand at an acid site (79.4-79.6 t/ha). The soil reaction is strongly acid to acid. The most favourable values of pH for forest floor and soil at acid (4.6 ± 0.4) and mesotrophic sites (5.2 ± 0.4) occur in the Douglas fir stand. It also corresponds to C/N ratio (23-26). The highest reserve of carbon in forest floor occurs at the acid site 34.7 t/ha (1.3 t/ha nitrogen). The lowest reserve of carbon in forest floor at the mesotrophic site amounts to 8.5 t/ha (0.4 t/ha nitrogen). The higher content of DOC in stands at acid sites can result in a higher risk of soil acidification. Keywords: spe

Productivity and cost of manual felling with a chainsaw in Caspian forests

F. K. Behjou, B. Majnounian, J. Dvořák, M. Namiranian, A. Saeed, J. Feghhi

J. For. Sci., 2009, 55(2):96-100 | DOI: 10.17221/69/2008-JFS

A field production study was conducted for a manual harvesting system using a chainsaw in a Caspian hardwood forest site. A selective cut was performed on a 42-hectare tract with an average slope of 30 percent. Felling time per tree was most affected by diameter at breast height and by the distance among harvested trees. The gross and net production rate was 20.6 m3 and 26.1 m3 per hour/one person, respectively. The unit cost considering the gross and net production rate was 1.05 USD/m3 and 0.81 USD/m3, respectively. The significant variables included diameter at breast height (D) and distance among harvested trees (L) for the time expenditure model. This regression function is statistically significant at α = 0.01.

Plant community variability within potential natural vegetation units: a case study from the Bohemian Karst

P. Šamonil, K. Polesná, P. Unar

J. For. Sci., 2009, 55(11):485-501 | DOI: 10.17221/111/2008-JFS

: Based on a map of potential natural vegetation (PNV), actual vegetation was studied in the Mramor locality (106.4 ha). A total of 188 relevés were examined using stratified random sampling. A comparison was made between trends in vegetation variability throughout the entire locality and variability within the defined PNV units. The stratification of the locality according to PNV units was only partly representative of the main trends in vegetation variability, especially at ecologically distinctive sites. On the other hand, in areas with a relatively limited ecological gradient, the sites were "oversampled". The variability of plant communities within PNV units was high. The results of this case study suggest that the need for delineation of PNV units which are homogeneous in terms of production, site and phytocoenosis is overestimated. This delineation neither corresponds to the characteristics of actual ecosystems nor is necessary for the application of a PNV system. A more suitable unit for the development of such a system would be, for example, forest type series.

Value production of poplar clones

R. Petráš, J. Mecko, V. Nociar

J. For. Sci., 2008, 54(6):237-244 | DOI: 10.17221/12/2008-JFS

The results of research on the value production of the stands of poplar clones Robusta and I-214 carried out in Slovakia are presented. Models of value yield tables were constructed separately for each clone. The models simulate gross and net financial yield of wood production in dependence on the site index and age of stand. They were constructed on the basis of the models of assortment yield tables, timber prices according to assortments and the models of own costs of timber felling and processing. The clone I-214 produces a faster and higher proportion of thicker assortments of average and below-average quality, and therefore it has the higher value production at a younger age only. Robusta produces smaller diameter but higher quality assortments and has the higher value production only at an older age. The site index of the stand is the most important factor in the value production of poplar clones. Differences in the production between site indexes are much greater than between the clones.

Forest yield index and its applicability to the assessment of future forest yields

L. Kulla, J. Tutka, R. Marušák

J. For. Sci., 2009, 55(1):41-50 | DOI: 10.17221/45/2008-JFS

The paper suggests and examines a simplified relative indicator of forest production, with special regard to possibilities of its use in projecting future forests. Forest yield index (IY), based on an economic parameter "value of final cutting yield" was proposed, and examined in the model territory of Kysuce in north-western Slovakia. The current values of final cutting yield, dependent on tree species, site index and the length of rotation period served as a basis for the assessment of expected yields. The possibilities and limitations of index applicability in long-term strategic forest management decision-making are discussed, considering the uncertainty of ecological and economic conditions during the long forest production cycle, as well as the complexity of tree species growth and production in the mixed forests, uneven aged forests and forests under climate change.

Comparison of deposition fluxes on the open area and in mountain spruce stands of different density

I. Marková, I. Drápelová, S. Truparová

J. For. Sci., 2009, 55(9):395-402 | DOI: 10.17221/37/2009-JFS

To better understand the chemical transformation of rainfall after the passage through the canopies it is necessary to study throughfall deposition fluxes within forest stands. The comparison of bulk deposition fluxes of Ca, Mg, K, S-SO4, N-NO3 and N-NH4 in mountain spruce stands of different stand density and bulk deposition fluxes on the open area was made at the study site Bílý Kříž (Moravian-Silesian Beskids Mts., Czech Republic) during the period of 1999-2006. A linear relationship between the amount of rainfall on the open area and the amount of throughfall in the spruce stand was found. Throughfall deposition fluxes of selected elements in the dense as well as in the sparse spruce stands were higher when compared with bulk deposition fluxes on the open area. There were mostly statistical significant differences between the bulk deposition fluxes on the open area and those in the studied spruce stands. The throughfall deposition fluxes of Ca, Mg, K and S-SO4 were influenced by the spruce stand density.

Assessing the short rotation woody biomass production on marginal post-mining areas

C. Böhm, A. Quinkenstein, D. Freese, R. F. Hüttl

J. For. Sci., 2011, 57(7):303-311 | DOI: 10.17221/94/2010-JFS

The Lusatian lignite-mining district (Eastern Germany) is characterized by a high share of marginal post-mining areas. At these sites, crop yield is generally low, and hence, conventional land use systems often fail in terms of reliable and efficient crop production. In this paper the attempt is made to evaluate the production of woody biomass for bioenergy in short rotation coppices (SRC) and alley cropping systems (ACS) with black locust (Robinia pseudoacacia L.) and lucerne (Medicago sativa L.) from the aspect of possible ecological and economic benefits compared to the conventional agricultural recultivation practice. The results show that, due to both high establishment and harvesting costs and comparatively low prices of energy wood, land use systems such as SRC or ACS are currently hardly profitable compared to conventional agriculture. However, the cultivation of black locust resulted in a higher humus accumulation and in a lower harvest-related nutrient export than the cultivation of lucerne as a typical recultivation crop in this region. Therefore, it can be concluded that for an improvement of soil fertility woody biomass production is more beneficial than the conventional agricultural recultivation practice.

Findings regarding ectotrophic stability of Norway spruce forest of the Krkonoše and Orlické Mountains based on mycorrhiza studies

V. Pešková, J. Landa, F. Soukup

J. For. Sci., 2011, 57(11):500-513 | DOI: 10.17221/139/2010-JFS

Analyses of root mycorrhizal samples and monitoring of fruiting bodies of macromycetes from Norway spruce stands at mountain and foothill localities in the Krkonoše and Orlické Mts. provided several data series allowing to assess and compare (albeit somewhat preliminarily) mycorrhizal conditions and macromycete incidence related to stand ages and location conditions. The overall mycorrhizal conditions in young (10 years old) and older (80 years old) stands on formerly agricultural soils are comparable to those in 80- and 90-year-old forests growing on standard forest soils, but young spruce stands in the Orlické Mts. replanted on forest soils do not surprisingly show any favourable mycorrhizal characteristics. The research documents a marked diversity of macromycete species composition in mountain spruce stands compared to foothill spruce stands on former agricultural soils. While in the younger mountain spruce stands of the Orlické Mts. the expansion of macromycete species composition began to develop in a similar fashion to that in the Krkonoše Mts., the comparison of older (80-year-old) stands on formerly agricultural soils in the Orlické Mts. foothills and Krkonoše Mts. implies that the macromycete species composition developed quite differently but with a similar success.

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