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    Wyświetlanie 1-6 z 6
    Tytuł:
    Teoria portfela w leśnictwie - optymalizacja składu gatunkowego drzewostanów
    Portfolio theory in the forestry - optimization of the species composition
    Autorzy:
    Klocek, A.
    Zając, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/985859.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    teoria portfela
    portfel inwestycyjny
    wskaznik Sharpe'a
    gospodarka lesna
    zarzadzanie ryzykiem
    minimalizacja ryzyka
    drzewostany
    sklad gatunkowy
    optymalizacja
    Opis:
    The paper presents the assumptions of the portfolio theory and the possibilities of its application in the forestry to diversify the species composition of the stand. The decision problem concerns the rationalization of the species share, ensuring the optimal ratio of annual production value from 1 ha in the stand (financial effect) to the expected level of risk. The adopted measure of the assessment of the value of production and the risk of its achievement is the Sharpe index, which is an approximate measure of the correlation between the income of one investment and its market, and therefore a measure of systematic risk. The paper presents the theoretical foundations of the mentioned optimization problem and examples of research results of American and European scientists regarding applications of portfolio theory in the forestry. The research results indicate that the portfolio theory in forestry focuses on making investment decisions in conditions of high uncertainty. The main criteria for selecting these decisions are income and risk. Diversification of the share of various investments is the source of the so−called risk diversification effects, e.g. the share of particular species in the composition of the stand, the assortment structure and other natural and economic factors that cause a reduction in the total risk with the same income or an increase in the total income with the same risk. The paper indicate that in forest management it is possible and justified to use the simplified Sharpe model, in the form of a univariate indicator, to analyze and make decisions rational from the point of view of natural and economic investment. This solution was applied to various portfolios, including the diversification of the species composition of tree stands. The key indicator when assessing the size of risk and related (predicted) income is the so−called the beta coefficient, determined using the modified Sharpe formula.
    Źródło:
    Sylwan; 2018, 162, 12; 971-979
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optymalizacja wieku dojrzałości rębnej drzewostanów z punktu widzenia wiązania węgla
    Optimizing the stand rotation age from the point of view of carbon sequestration
    Autorzy:
    Wysocka-Fijorek, E.
    Zając, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/988959.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    gospodarka lesna
    drzewostany sosnowe
    drzewostany bukowe
    dojrzalosc rebna
    wiek dojrzalosci rebnej
    optymalizacja
    wiazanie wegla
    wzory empiryczne
    wspolczynniki przeliczeniowe
    optimization of the rotation age
    carbon dioxide accumulation
    timber production
    Opis:
    The selection of the rotation time of a stand (from planting to final felling), i.e. the age at which stand reaches harvest maturity, is a key decision in forest management due to, inter alia, the amount and value of carbon stored in the forest. In this context, the basis for the economic optimisation of the rotation age of forests is to define the goal of forest production and desirable state of forests ensuring the achievement of the adopted aim. Therefore, the choice of the most suitable optimal moment of completing a production cycle and starting the subsequent one is very important in forest management. The aim of the performed analysis is to verify the empirical equations and conversion factors as well as to assess their suitability for determining the volume and value of standing timber and accumulation of carbon in the aboveground woody biomass. The verified equations will be used for modelling the optimal rotation age of forests due to the maximization of the rate of carbon accumulation in the aboveground woody biomass. The input data for the verification of equations and conversion factors were grouped according to the dominant species, 10−years age subclass and site index class. Four methodological approaches were used to analyse and estimate the amount of carbon accumulated in the aboveground woody biomass. With the assumption of a continuous use of forest land for timber production, the generated revenues will be same at the same level of costs in the subsequent production cycles. Analysing the results of the optimization of the age of felling maturity it should be noticed that these are the averaged values relating to the State Forests. They do not take into account local differences in the price of raw wood and production costs including the specific characteristics of individual trees or stands. The accuracy (quality) of calculating the average and current increment of stands and, in consequence, of the amount and value of the accumulated carbon is important for the effectiveness of the optimization of the amount of carbon accumulated in the aboveground woody biomass.
    Źródło:
    Sylwan; 2017, 161, 11; 883-891
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wybrane cechy gospodarki lesnej w Polsce na tle krajow europejskich
    Selected parameters of forest management in Poland against the background of European forests
    Autorzy:
    Zajac, S.
    Lotz, D.
    Mlynarski, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/46160.pdf
    Data publikacji:
    2009
    Wydawca:
    Instytut Badawczy Leśnictwa
    Tematy:
    lesnictwo
    zasoby lesne
    gospodarka lesna
    lasy
    stan zdrowotny lasu
    ochrona lasu
    szkody w lesie
    produkcja drewna
    rynek drzewny
    Polska
    Unia Europejska
    Źródło:
    Leśne Prace Badawcze; 2009, 70, 4; 411-418
    1732-9442
    2082-8926
    Pojawia się w:
    Leśne Prace Badawcze
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ekonomiczna efektywność naturalnego i sztucznego odnowienia drzewostanów sosnowych w Nadleśnictwie Nowa Dęba
    Economic effectiveness of natural and artificial regeneration of Scots pine stands in the Nowa Deba Forest District
    Autorzy:
    Długosiewicz, J.
    Zając, S.
    Wysocka-Fijorek, E.
    Powiązania:
    https://bibliotekanauki.pl/articles/985715.pdf
    Data publikacji:
    2019
    Wydawca:
    Polskie Towarzystwo Leśne
    Tematy:
    lesnictwo
    gospodarka lesna
    drzewostany sosnowe
    odnowienia lasu
    odnowienia naturalne
    odnowienia sztuczne
    efektywnosc ekonomiczna
    ocena ekonomiczna
    Nadlesnictwo Nowa Deba
    scots pine
    natural regeneration
    artificial regeneration
    costs
    effectiveness assessment
    Opis:
    A prerequisite for effective forest management is a detailed economic analysis of given management determinants. In the forest district’s expenditures, next to the wood harvesting and skidding, the cost of silvicultural activities constitute a considerable share. The choice of forest management methods, including those for forest regeneration has a significant effect on the costs incurred for silvicultural activities as well as on the quality of emerging new generation. The aim of the study was to assess the economic effectiveness of Scots pine stand management using natural and artificial regeneration. The research determined the size and structure of expenditures incurred for the establishment and maintenance of crops. We also carried out the analysis and assessment of the effects of the selected regeneration method on forest management economic efficiency. The economic analysis included the comparison of the costs of establishment and maintenance of stands with artificially regenerated Scots pine trees with the costs of analogous activities carried out within the research plots with Scots pine from self−seeding. The studies were carried out on 4 types of forest sites, i.e.: fresh coniferous, fresh mixed coniferous, wet mixed coniferous and fresh mixed deciduous. The analyses were carried out using the cash flow method – the stream of expenditure incurred for stand management. The total costs of artificial stand regeneration and maintenance were on average higher by 1,443.24 PLN/ha of plantation as compared to naturally regenerated stands. Lower costs of tending and corrections performed in artificially regenerated Scots pine stands did not compensate for high expenditure incurred on regeneration activities, and as a result the total cost amounted to an average of 5,002.94 PLN/ha, whereas in the case of natural regeneration the total cost was 3,559.70 PLN/ha. In the analysed methods, the site conditions were of great importance to the amount of expenditures incurred for stand regeneration and maintenance. The economic viability of forest natural regeneration was confirmed for fresh coniferous, fresh mixed coniferous and wet mixed coniferous habitat types. In fresh mixed deciduous site, high costs of tending treatments and corrections had a major effect on the low economic result of the natural method of forest regeneration. The presented results on the effectiveness of management of Scots pine stands or those with the predominance of Scots pine using natural and artificial regeneration can be an important factor in taking appropriate silvicultural decisions, based on the assessment and knowledge of determinants affecting profitability of undertakings.
    Źródło:
    Sylwan; 2019, 163, 05; 373-384
    0039-7660
    Pojawia się w:
    Sylwan
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-6 z 6

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