Non-wood forest products (NWFPs) contribute economically to all countries of the world and they are an important source of income, especially for people living in or near the forest. They are also used in many sectors such as medicine, chemistry and paint industry. In this respect, the importance of NWFPs is increasing day by day. In this research, the comparative advantage of NWFPs of Turkey was analyzed. In the analysis of research, it was used the revealed comparative advantage, relative trade advantage, and revealed competitiveness. The research is based on secondary data pertaining to the period 2008–2019. Moreover, in order to determine periodic trends, the determined period was evaluated in two sections covering the periods of 2008–2013 and 2014–2019. It has been found that Turkey had a strong competitiveness in NWFPs between years 2008 and 2019. When NWFPs were examined at subgroup level, Turkey has a comparative advantage in the subgroups 8. Furthermore, it was revealed that the competitive advantage of the period 2008–2013 is higher than of the period 2014–2019.

Keywords: non-wood forest products, comparative advantage, trade, exports

   Reuse of materials from industrial and services waste streams is pertinent to achieving sustainable forest production. The enormous wood residues generated at sawmill and the disposal of wood-based products poses threat not only to sustenance of the forest resources but also has negative adverse effect on the environment. Limitation exists in the utilization of wood residues as raw material for panel board production in developing countries. This study examined the physical and mechanical properties of graded density fibreboards produced from varying mixture of sawdust and corrugated paper (pulp) at the Forestry Research Institute of Nigeria (FRIN) in 2019. A 2×9 factorial experiment in one-way analysis of variance was used to test for significant difference between the factors (density and mixing ratio) considered. The results showed that densities of all boards produced varied relating to mixing proportions. The densities increased with increasing content of corrugated paper. Boards produced at 0.45 g/cm³ showed higher density (0.648 g/cm³), bending strength (MOR) (1.47 N/mm²) and lesser water absorption (118.69%) than those produced at 0.65 g/cm³ having values of 0.58 g/cm³, 1.32 N/mm² and 153.67%, respectively. However, boards produced at 0.65 g/cm³ had higher elasticity in bending (MOE) (209.19 N/mm²) and lesser thickness swelling (6.29%) than those produced at 0.45 g/cm³ having values of 74.87 N/ mm² and 10.88%, respectively. Panels G (mixing ratio = sawdust : corrugated paper : urea formaldehyde = 20 : 60 : 20), E (30 : 50 : 20) and I (0 : 70 : 20) showed superior features in physical and mechanical properties comparing with panel I being the best mixture. Conclusively, wood residues (sawdust and corrugated paper) are suitable raw materials for fibreboard production.

Keywords: wood residues, reuse, fibreboard, density, physico-mechanical indices

   When measuring in a forest inventory, height and diameter at breast height are basic variables. Generalised models do not require measuring tree heights, and the number of measurements is minimal. However, the opinions of researchers differ in both the number of variables included in the model and in the number of parameters. The purpose of this study was to obtain 24 new generalised height-diameter models based on simple ones, compare them with 9 generalised models selected from other studies, and develop an appropriate height-diameter model for birch in the European part of Russia. The article shows that even in simple cases, there is a wide variety of options for generalised models. Moreover, models with three independent variables may be necessary and sufficient. These are the diameter at breast height, quadratic diameter at breast height, and the mean height. The performance statistics showed that modified power function is the most suitable and, therefore, it is recommended for predicting the height-diameter relationships for birch trees in this study area. The predicting variables for applying developed generalised models to estimate total tree height require less sampling effort. They derive from conventional forest inventory data which cuts costs and saves time during fieldwork.

Keywords: generalised model, height-diameter relationship, total tree height, diameter at breast height, birch stand, European Russia

   The quality and quantity of valuable natural areas is assessed through the prism of benefits derived from all the functions performed by them, among which tourist and recreational functions play an increasingly important role. The main purpose of this paper was to determine economic benefits obtained by tourists visiting the “Nad Tanwią” nature reserve located in the south-eastern part of Poland, calculated using the travel cost method, TCM. The survey method was used as part of the research. Surveys were conducted from May to September 2017 on a group of 341 respondents. Data regarding the length of the visit and the amount of costs related to the stay in the reserve were subject to statistical analysis using the CART method. The results of the survey showed that the respondents reported a need for 14 types of visits depending on their duration. The value of the consumer surplus amounted to PLN 986/person, and the value of the gross benefit amounted to PLN 1,069/ person. The value of the consumer surplus, which was the share of tourists visiting the reserve during the year, amounted to PLN 108 million, and the gross value of non-market benefits for this group was PLN 118 million. The developed model of travel costs in the reserve allows for the assessment of recreational benefits of this place. The development of tourism and recreation in areas attractive in terms of nature contributes to improvement regarding meeting recreational needs of tourists and the existing transportation infrastructure.

Keywords: leisure, tourism, valuation, protected area, “Nad Tanwią” nature reserve, travel cost method, consumer surplus