Start  Wyszukiwarka artykułów
Control BreakRok  Remove Breaks
Control BreakZeszyt  Remove Breaks
View Chart
1 - 15 Next
Rok : 2014, Zeszyt : 09
Wielowymiarowa analiza bankructwa przedsiębiorstw w przemyśle drzewnym
Multivariate analysis of bankruptcy in companies in the wood sector

Abstract: The article describes the accuracy of Altman and Mączyńska predictive models. The research material consisted only of financial economic reports from wood−furniture sector for years 2003−2012. Multiple discriminant analysis (MDA) was the main method applied in the study and which was used for three years in advance before bankruptcy. To evaluate the accuracy of the analysed models, the companies classification matrix and the odds ratio were used. Obtained results showed higher prediction accuracy of Mączyńska model. Moreover, comparing with the Altman model, Mączyńska system was better adapted as a multiple discriminant analysis model allowing forecasting of bankruptcy and continued functioning of companies in the wood sector.

Key words: forestry economics, prediction, discriminant analysis, bankruptcy

[SYLWAN 158 (9):643-650, 2014]

Planowanie hodowlane w drzewostanach jodłowych o złożonej strukturze z wykorzystaniem metody BDq w Nadleśnictwie Zagnańsk
Silvicultural planning in complex structures of silver fir by means of the BDq method in Zagnańsk Forest District

Abstract: The paper deals with problems concerning silvicultural planning in silver fir stands in Zagnańsk Forest District (central Poland) that are characterized by complex structure. Based on a detailed inventory using 98 permanent circular sample plots in four control units the BDq method was employed for determining the future silvicultural activities of the current forest management cycle. The equilibrium model is based on diameter distributions and has the following parameters: B=35 m²/ha; D=63 cm and q−factor=1.28.

Key words: close−to−nature silviculture, complex stand structure, multifunctional forestry, silver fir, silvicultural planning

[SYLWAN 158 (9):651-660, 2014]

Zmiany składu gatunkowego i stopnia pokrycia przez rośliny na powierzchniach zaburzonych przez huragan na terenie Puszczy Piskiej w 2002 roku
Changes in species composition and cover of understory plants in stands disturbed by a hurricane in Piska Forest in 2002

Abstract: Comparison of understory of stands disturbed by hurricane and managed ones allowed to distinguish two phases that include degenerative and regenerative changes. In the first phase, which lasted about 6 years, following processes were observed: chaotic changes in species composition, invasion of exogenous species, increase in cover of Deschampsia flexuosa and Vaccinium vitis−idaea, decrease in moss cover and Vaccinium myrtillus as well. In the second phase changes had opposite direction. Structure of ground flora typical to Scots pine forest was slowly developing. Increasing shade of forest floor, caused by growing shrub layer and regeneration of tree species, was a key factor of the regeneration process.

Key words: disturbance, windthrow, regeneration, Szast Protected Forest

[SYLWAN 158 (9):661-668, 2014]

Wpływ odnowienia lasu zrębem zupełnym na trofizm gleb rdzawych na przykładzie Nadleśnictwa Spała
Trophic soil index of the rusty soils affected by clear−cutting in the Spała Forest District

Abstract: The paper describes the influence of clear−cutting on the fertility of rusty soils expressed by trophic soil index. Soils in the Spała Forest District (central Poland) were covered by coniferous or mixed coniferous forests. Clear−cutting in acidic and oligotrophic mixed coniferous forests decreased soil fertility and affected an increase of hydrolitic acidity, particularly in Oh and Bv horizons. This type of timber harvest influenced also decrease of organic carbon in the first year after cutting.

Key words: forest soils, trophic soil index, forest soil quality, soil organic carbon

[SYLWAN 158 (9):669-674, 2014]

Relacje między typem siedliskowym lasu a zbiorowiskiem roślinnym w warunkach górskich
Relationships between forest habitat types and phytosociological classification in mountain environment

Abstract: Two main typological systems (forest habitat types and phytosociological classification) are used in forest research in Poland. The paper presents relationships between forest associations and forest habitat types in mountain environment of the Promotional Forest Complex ‘Sudety Zachodnie' (SW Poland). The results show that the link between these two topological systems is rather weak and ambiguous. This has strong implications for nature conservation in Poland, where forestry databases are widely used for inventories of protected habitats (in the sense of Habitat Directive).

Key words: forest habitat types, phytosociological classification, syntaxonomy

[SYLWAN 158 (9):675-683, 2014]

Wpływ drzewostanów o zróżnicowanym udziale świerka na gleby różnych typów siedliskowych lasu w Górach Stołowych
Influence of stands with diversed share of Norway spruce in species structure on soils of various forest habitats in the Stołowe Mountains

Abstract: Chemical properties and fertility of soils were compared under spruce, mixed and beech stands in four types of forest habitat (mountain broadleaf forest, mountain mixed broadleaf forest, mountain mixed coniferous forest and mountain coniferous forest) in 373 sites of forest monitoring in the Stołowe Mountains National Park, SW Poland. Soils under the spruce stands had higher organic carbon pools in their upper horizons, but lower pH, increased activity of exchangeable aluminum, lower contents of exchangeable base cations, available potassium and magnesium, resulting finally in lower values of the soil trophic index (SIG). The negative impact of spruce monocultures on the physicochemical soil properties was much stronger in the eutrophic habitats (dedicated to broadleaf forest) than in dystrophic ones. Weak positive effect of the beech introduction on soils in the dystrophic habitats indicated that the conversion of the coniferous into mixed or deciduous stands would not cause a rapid improvement in the physicochemical properties deformed previously under spruce monocultures.

Key words: pH, organic carbon, soil fertility, forest habitat type, trophic soil index

[SYLWAN 158 (9):684-694, 2014]

Zmiany w dwóch zespołach buczyn pomorskich w rezerwacie Kołowskie Parowy (Puszcza Bukowa) w latach 1985−2006
Changes in two Pomeranian beech forest communities in the Kołowskie Parowy nature reserve (Bukowa Forest) between 1985 and 2006

Abstract: The paper presents the analysis of changes in two beech forest communities in the Kołowskie Parowy nature reserve (NW Poland). Within 21 years the frequency and cover of most species significantly decreased, including typical taxa for shady deciduous forests. Analysis of ecological indicator values showed that species richness is strongly correlated with light availability. The results suggest that passive protection promoted in Puszcza Bukowa forest brings negative effects for vascular plants biodiversity.

Key words: beech, nature protection, forest management, biodiversity, gaps

[SYLWAN 158 (9):695-703, 2014]

Zmiana powierzchni zbiorowisk o charakterze leśnym w dolinie Karpnickiego Potoku jako przykład zmian lesistości w dolnych partiach Sudetów
Changes in the area covered by woody plants communities in the Karpnicki Potok valley as an example of changes in forest area in lower parts of the Sudety Mountains

Abstract: On the basis of historical and recent cadastral maps, topographic maps, and aerial photographs, we analysed changes in forest area within the cadastral units of Karpniki village, in the Karpnicki Potok (SW Poland). In 1823−2012, forest area increased there from about 41% to over 57% of the total area. The greatest increase has been recorded recently. Moreover, at that time over 16% of land classified officially as farmland was naturally colonized by communities dominated by woody plants. This seminatural process in the analysed case does not pose any serious threat to natural resources, but a complete lack of its control may lead to deterioration of the value of the local landscape and development of low−quality forest stands. The observed changes seem to be typical of other areas located in lower parts of the Sudety Mountains.

Key words: increase of forest area, lower parts of the mountains, seminatural succession, landscape

[SYLWAN 158 (9):704-713, 2014]

Wpływ gryzoni na regenerację lasu z uwzględnieniem zaburzeń naturalnych i antropogenicznych
Influence of the rodents on forest regeneration considering natural and anthropogenic disturbances

Abstract: The role of the rodents in forest regeneration includes both negative (seed and seedlings consumption) and positive (seed dispersal) aspects. The objective of this paper is to review the knowledge of this dual effect of the rodents on forest regeneration after disturbance, particularly in temperate managed forest stands. Many studies have demonstrated that consumption of seeds and seedlings by rodents can substantially inhibit regeneration of forest stands after disturbance. Small mammal predation on oak, pine and European beech seeds and seedlings contributes to reduced forest regeneration after tree harvest and natural disturbances such as fires. On the other hand, some rodent species may promote seed dispersal towards deforested areas. Moreover, they frequently prefer nesting and caching of acorns near structures providing shelter. Such structures are abundant in disturbed areas and appear to promote higher survival of cached seeds. Furthermore, there are certain techniques of seed and seedling protection against small mammals, e.g., planting seeds in the soil, using polyethylene tubes to raise seedlings, or providing alternative food for rodents. The positive impact of the rodents can be enhanced and negative minimized through proper management, such as providing appropriate microhabitats for seed caching, or maintaining continuity of canopy cover/forest stands.

Key words: anthropogenic disturbances, forest management, forest regeneration, natural disturbances, rodents

[SYLWAN 158 (9):714-720, 2014]

Rok : 2014, Zeszyt : 08
Wzrost i przyrost wysokości dębu szypułkowego (Quercus robur L.) w dolnej warstwie drzewostanu sosnowego
Growth and increment of height of pedunculate oak (Quercus robur L.) undergrowth in Scots pine stands

Abstract: The study compares height growth of pedunculate oak (Quercus robur L.) undergrowth in Scots pine (Pinus sylvestris L.) stands and in open canopy conditions. Material was collected in 20 Scots pine stands with well−developed pedunculate oak undergrowth located in north−eastern Poland, representing the mixed deciduous forest type (Querco roboris−Pinetum). Fraction of oak undergrowth with slow height increment in Scots pine stands amounted 40% and was twice as high as in the open canopy conditions. On average 10 years longer than in the open canopy conditions juvenile phase characterizes the height growth of pedunculate oak undergrowth. A shift of height growth phases of oak undergrowth was recorded. However in most of the stands Scots pine shelter did not cause large delay in the age at which the culmination of current height increment of pedunculate oak is achieved.

Key words: height, growth phases, undergrowth, pedunculate oak

[SYLWAN 158 (8):563-570, 2014]

Nowy wariant modelu ryzyka uszkodzenia drzewostanu przez wiatr
New variant of the wind damage risk model for forest stands

Abstract: The paper presents a new variant of the wind damage risk model for forest stands in view of its application in the forests under private ownership. It was based on the following characteristics: average height, age and slenderness of the main tree species, stand density index, species composition, forest habitat type, as well as stand location in the region of the country and the volume of windbreaks, windfalls and deadwood in previous years. The latter characteristic in the new model variant is generated by the stand damage model. The new wind damage risk model variant determines the risk factor for individual stands ranging from 0 to 3. A higher value of the factor indicates a higher wind damage risk for the stand. The verification of the model was performed using the forest data from two counties (powiat) situated in the Podkarpackie Province. The wind damage risk factors obtained from the model are shown on numerical maps.

Key words: wind damage, risk factor, private forests

[SYLWAN 158 (8):571-578, 2014]

Tabele wiekowe dla drzew z wczesnosukcesyjnych drzewostanów brzozy brodawkowatej (Betula pendula Roth) na gruntach porolnych
Age tables for silver birch (Betula pendula Roth) trees for early succession stands on abandoned agricultural lands

Abstract: The paper presents the tables for indirect determination of the age of silver birch (Betula pendula Roth) trees basing on easy to measure dendrometric parameters. We elaborated empirical formulae that enable determination of tree age using total tree height, breast height diameter and stump diameter as the predictors. Data was collected in 40 pure silver birch stands growing on former farmlands in Mazowsze region (central Poland). Sample material consisted of data from the stem analyses of 200 trees and measurements of 600 stumps. Obtained equations explain 70−86% of the age variability. The best fit was achieved for joint use of total tree height and breast height diameter as the independent variables.

Key words: age tables, silver birch, early succession, abandoned agricultural lands, age models

[SYLWAN 158 (8):579-589, 2014]

Drzewotocz japoński Xylosandrus germanus (Bldf.) (Coleoptera: Curculionidae, Scolytinae) w Polsce
Xylosandrus germanus (Bldf.) (Coleoptera: Curculionidae, Scolytinae) in Poland

Abstract: The information about the occurrence of the invasive bark beetle Xylosandrus germanus (Bldf.) in Poland is presented. A set of traits enabling its distinguishing from similar Anisandrus dispar is provided.

Key words: bark beetle, invasive, Poland

[SYLWAN 158 (8):590-594, 2014]

Wpływ warunków świetlnych na namiotnika czeremszaczka – głównego szkodnika czeremchy zwyczajnej
Light conditions effect on bird cherry ermine moth – the main pest of bird cherry

Abstract: This article studies the effect of light and high temperature on various parameters describing the growth and development of bird cherry ermine moth (Yponomeuta evonymellus L.) – the main pest of bird cherry (Prunus padus L.). We found that light significantly influences the moth masses and dynamics of their development. Moths developed from larvae feeding on leaves growing in full light conditions have a higher mass and shorter time of adult eclosion from pupa in comparison with larvae feeding on leaves growing in shade. However, extremely high summer temperature significantly disturbs pupation process in Y. evonymellus population. Our laboratory experiments indicate that a critical temperature is 36°C. Above this threshold the percentage of pupation drastically decreases (from ca. 70% to 35%). The conditions of intensive sun are better for some parameters of growth and development of bird cherry ermine moth. On the other hand, extreme summer temperatures, related with global warming, may restrict the occurrence of Y. evonymellus gradation.

Key words: folivorous insect, global warming, high temperature, leaf toughness

[SYLWAN 158 (8):595-603, 2014]

Wpływ zastosowania trocin w uprawie jednorocznej sosny zwyczajnej na liczebność pędraków chrabąszczy
Effect of sawdust addition into one−year−old Scots pine plantation on number of Melolontha grubs

Abstract: Number of Melolontha grubs in forest soils reforested with Scots pine (Lubartów A, LA, Lubartow B, LB) and those in post agricultural soils afforested with this species (Swierczyna, SW) were assessed before (autumn 2011, spring 2012) and one year after (2013) planting. At the same time, mortality of seedlings was evaluated on both study sites. Pine sawdust was mixed with soil in rows (treatment T1) or applied under seedling roots just before planting in April 2012 (treatment T2). In May 2013, seedling mortality varied significantly, from 27.5% in LB to 51.0% in LA, whereas the differences between the treatments were not significant. The mean number of Melolontha grubs decreased from 35/0.15 m³ of soil in autumn 2011 to 3/0.15 m³ in spring 2012 and in spring 2013. The differences depended on the site, treatment and grubs spatial distribution in soil. Addition of sawdust did not influence either seedlings, or insects mortality. T2 was more beneficial for Scots pine seedlings growing on agricultural soils, while treatment T1 – for those on forest soils. On the other hand, pine sawdust applied under roots of the seedlings seemed to attract Melolontha spp. grubs.

Key words: Melolontha, frequency, Scots pine, seedlings, mortality, sawdust, soil

[SYLWAN 158 (8):604-613, 2014]

1 - 15 Next

Zakład Informatyki Lasów Państwowych
Aplikacje internetowe i obsługa informatyczna · NetExpert