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  • Author: Stanisław Zając x
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Delimitacja rekreacyjnej funkcji lasów i gospodarki leśnej na terenach zurbanizowanych

Abstract

The bad economic situation for agro-forest farms in Poland during the interwar period was caused by war damage, a global economic crisis, crop failure, indebtedness prior to World War I, and by tribute payments towards rebuilding the country. Although the timber harvest was substantial, farm owners were forced to take loans. In 1938, the debt level of agro-forest farms accounted for 18 per cent of their total value. The average debt level for this period oscillated between 9.8 and 126.0 PLN/ha-1. The assistance programme implemented by the government provided for a reduction in the interest rate of loans, particularly for farms with an area up to 300 ha.

Abstract

This article describes the methods for estimating the value of a forest, the accuracy of which is critical for purchases and sales, credit security, determining the shares in the division of forest real estate, as well as in determining the amount of compensation for losses in forest property. Compensation for property losses also includes past events that occurred before the Second World War, such as nationalization or loss of the forests in the eastern territories of the Second Polish Republic due to border changes. An equally important objective of forest valuation, which has recently gained in importance, is the inclusion of its value in a forest holding balance sheet. However, due to the lack of fully objective market prices for forest property, this work focused on the analysis of the quantitative and qualitative characteristics of the forest market and the methods of calculating the income (rent) value of the forest. Examples of commercial transactions from the forest market in the USA, Austria and Germany are included.

The study presents a historical outline of forest valuation with particular emphasis on methods based on the income value, including forest rents. Furthermore, we discuss the formula of the perpetual capitalization of annuity and periodic annuity, including the impact of various net income calculations, that is, in arrears or in advance

Wybrane cechy gospodarki leśnej w Polsce na tle krajów europejskich

The Influence of Sodium Phosphate Supplementation on VO2max, Serum 2,3-diphosphoglycerate Level and Heart Rate in Off-road Cyclists

The main objective of the work was to evaluate the influence of a six day supplementation with sodium phosphate on circulatory and pulmonary variables, the level of 2,3-diphosphoglycerate (2,3-DPG) and the concentration of inorganic phosphates in blood serum of elite off-road cyclists. The research material included 19 cyclists which were randomly divided into a experimental group, supplemented with sodium phosphate and a control group receiving a placebo The subjects in the experimental group ingested sodium diphosphate in a dose of 50mg/kg of fat free mass per day. The supplement was ingested in even doses, four times per day. The control group received 4g of glucose in gelatin capsules (500mg), which were also divided into 4 even portions. During the experiment a significant (p<0.05) increase in maximal oxygen uptake was observed (VO2max), maximal minute ventilation (VEmax), as well as oxygen pulse (O2/HR). Also a significant decrease in resting and maximal exercise heart rate occurred. This was also true for each exercise load. A significant (p<0.05) increase in the serum concentration of non-organic phosphates (P) was observed which was accompanied by a decrease in serum calcium (Ca) concentration. The changes in the resting and post exercise concentration of 2,3-DPG were non significant, yet the supplementation procedure showed a tendency for increased level of this variable.

The Effects of Terminating Creatine Supplementation and Resistance Training on Anaerobic Power and Chosen Biochemical Variables in Male Subjects

The main objective of this study was to investigate the effects of alkaline creatine supplementation and resistance training termination on anaerobic power and chosen biochemical variables in men. Twenty-three untrained male subjects, which participated in this study, were divided into supplemented (S) (n=13, age 21.4±2.3 y) and placebo (PL) (n=10, age 22.1±2.6 y) groups. The participants from both groups performed resistance training 3 times a week, while subjects from group S were supplemented with alkaline creatine (ACr) for 4 weeks on their training day's with 66.8 mg/kg b.m., and on non training day's with 33.8 mg/kg b.m.

To evaluate anaerobic power, the 30s Wingate test was applied. The following variables were registered: relative mean power - RMP (W/kg), relative peak power - RPP (W/kg), time of reaching peak power - TRPP (s) and relative total work - RTW (J/kg). The test was administrated 5 times - before and after 4 weeks of training and supplementation, as well as the first, second and third week after terminating creatine intake and the resistance exercise protocol. Body mass and body composition was also evaluated during the same time span. Blood samples were drawn at rest before the Wingate test for the assessment of IGF-1, hGH, LA and CrN concentration, as well as creatine kinase (CK) and lactate dehydrogenase (LDH) activities. Supplementation with alkaline creatine, combined with a progressive resistance training program, did not significantly influence (ANOVA) the level of RMP (p=0.49), RPP (p=0.31), TRPP (p=0.51), and RTW (p=0.58) in untrained male subjects. In the supplemental group, there was a significant decrease (p<0.01) in TRPP following creatine supplementation and training, yet these values were not significantly different from the control group. The supplementation and training protocol did not influence significantly body mass (p=0.68), yet post hoc analysis indicate a significant increase in body mass (p<0.001) only in group S. The applied supplementation and training protocol did not influence (ANOVA) the concentration of serum CrN (p=0.81), hGH) (p=0.26), CK (p=0.49) and LDH (p=0.64) activities. No significant changes were observed in resting blood LA concentrations of the tested subjects. It can be concluded that the ergogenic effect of creatine intake and resistance training was maintained for a week after terminating supplementation and exercise. During the next 2 weeks de-adaptation occurred and most indices of anaerobic power returned to initial values.

Abstract

The central task of this research was to choose the age at which stands of growing timber should be harvested. The choice governs how long each stand must continue to earn interest, and also governs the size of the total inventory that must be maintained to sustain the annual harvest. It is a problem that calls for analysis of biological as well as economic relationships over time, and has intrigued economists for more than two centuries. The paper presents the theoretical background and results of economic optimization of the rotation age of a single stand. It analyses the timber production function depending on rotation age, growth, cost and other characteristics of forest, as well as the costs of land. The prerequisite for achieving the economic optimum of the rotation age of a stand is to balance the current increase in the total timber production value (growth and yield) and the value of opportunity costs from delaying cutting till the next year. This paper demonstrates how this economically optimum rotation age can be calculated, and how it varies according to the biological growth and economic parameters of the forest.

Abstract

The paper provides general information about forests and forestry in Poland against a background of other EU Member States. Based on the data published in various international sources of statistical data it presents the information of forest resources, forest health condition, protection of forests, occurrence of forest fires, employment in forestry and related sectors, as well as selected aspects of production and trade of wood and wood products and also generation and use of renewable energy. The paper concludes that Poland is characterized by vast forest and timber resources, however in view of a large area of the country and large population share of forest lands in the total area of the country and the average forest area per inhabitant are low. The high share of protected areas makes Poland one of the leaders in forest protection, however Polish forests are very vulnerable to fires. Poland is a significant producer of wood-based panels, sawnwood and pulpwood, as well as paper and cardboard.

Abstract

The aim of the present study was to evaluate the efficacy of 3-week high intensity interval training in normobaric hypoxia (IHT) on aerobic capacity in basketball players. Twelve male well trained basketball players, randomly divided into a hypoxia (H) group (n=6; age: 22±1.6 years; VO2max: 52.6±3.9 ml/kg/min; body height - BH: 188.8±6.1 cm; body mass - BM: 83.9±7.2 kg; % of body fat - FAT%: 11.2±3.1%), and a control (C) group (n=6; age: 22±2.4 years; VO2max: 53.0±5.2 ml/kg/min; BH: 194.3 ± 6.6 cm; BM: 99.9±11.1 kg; FAT% 11.0±2.8 %) took part in the study. The training program applied during the study was the same for both groups, but with different environmental conditions during the selected interval training sessions. For 3 weeks, all subjects performed three high intensity interval training sessions per week. During the interval training sessions, the H group trained in a normobaric hypoxic chamber at a simulated altitude of 2500 m, while the group C performed interval training sessions under normoxia conditions also inside the chamber. Each interval running training sessions consisted of four to five 4 min bouts at 90% of VO2max velocity determined in hypoxia (vVO2max-hyp) for the H group and 90% of velocity at VO2max determined in normoxia for the group C. The statistical post-hoc analysis showed that the training in hypoxia caused a significant (p<0.001) increase (10%) in total distance during the ramp test protocol (the speed was increased linearly by 1 km/h per 1min until volitional exhaustion), as well as increased (p<0.01) absolute (4.5%) and relative (6.2%) maximal workload (WRmax). Also, the absolute and relative values of VO2max in this group increased significantly (p<0.001) by 6.5% and 7.8%. Significant, yet minor changes were also observed in the group C, where training in normoxia caused an increase (p<0.05) in relative values of WRmax by 2.8%, as well as an increase (p<0.05) in the absolute (1.3%) and relative (2.1%) values of VO2max. This data suggest that an intermittent hypoxic training protocol with high intensity intervals (4 to 5 x 4 min bouts at 90% of vVO2max-hyp) is an effective training means for improving aerobic capacity at sea level in basketball players.

Abstract

New challenges related to the multifunctional role of forests in consideration of both natural environment and economy come into view sequentially. In current forestry practice, an important element is not only the quality of forest cultivations (silvicultural aspect) but also the costs incurred for their production and tending (economic aspect).

The main purpose of this article is to show the prospect of increasing positive silvicultural effects depending on the method used in management of Scots pine stands under given site conditions. The comparative analysis was carried out using the study results obtained in the Forest District Nowa Dęba and those presented in other relevant studies. In the present study, we examined whether the site conditions have significant effects on silvicultural and economic effectiveness of regeneration and development of Scots pine stands or those predominated by Scots pine in the initial stages of stand growth. Significance of the regeneration method effects on growth characteristics of Scots pine regeneration as well as the costs of forest cultivation management was analysed.

The study on silvicultural and economic effectiveness was carried out in the Forest District Nowa Dęba. The results obtained showed that using Scots pine natural regeneration under the conditions of fresh coniferous forest site and fresh mixed coniferous forest site was the way of management based on reason. This was supported by both the values of regeneration growth parameters and silvicultural quality along with clearly lower expenditures incurred to achieve these effects. In wet mixed coniferous site, Scots pine seedlings regenerated naturally; however, the results indicated their lower silvicultural quality and growth parameter values when compared to those artificially regenerated. In fresh mixed broadleaved forest site, equally for silvicultural and economic reasons, the more optimal option was to regenerate forest using traditional planting material as natural Scots pine regeneration showed lower silvicultural effects. The unit costs of regeneration and maintenance of stands with self-sown Scots pine in fresh mixed broadleaved forest site were higher when compared with other examined forest sites.

On the basis of the results of the present study, it can be concluded that regardless of the regeneration method examined, the most differentiating factor of the final economic effect of Scots pine stand establishment and maintenance was the cost of regeneration operation. The expenditure for this purpose consumed the largest part of expenses incurred in artificial regeneration variant. The higher cost of corrections in artificially planted forest cultivations in poorer forest sites was one of the reasons behind the profitable final balance of naturally regenerating Scots pine stands. Differences between other costs analysed were not significant.

The results of the present study may contribute to comprehensive assessments of natural and artificial ways of forest regeneration and indicate forest production costs that are the most closely related to site conditions.