A small-scale R&D project, including a block with four plots (P1-4) of 200 m2, was established in 2001 in a 15-year-old sessile oak-dominated stand, regenerated naturally through the application of group shelterwood cutting. In each plot, “potential” final crop trees were selected, based on vigour-quality-distribution criteria, and painted. Silvicultural interventions (cleaning-respacing and thinning), of different types and intensities were performed in P1-3 (P4 was kept as control) as well as P5 (500 m2), established in 2009, in 2001, 2004, and 2009. The mortality intensity between 2001 and 2019 was the highest in P4 and the lowest in P1, with the minimum stand density. Sessile oak showed the highest mortality, followed by Hungarian oak and Turkey oak. The fastest diameter growers were the “potential” final crop trees, their quadratic mean diameter (QMD) reaching values close to 20 cm at 35 (30-40) years in the plots with the lowest stand density. In all plots, trees have reached heights corresponding to the QMD of ca. 15 m, which are typical to a sessile oak stand of high productivity (production class II). The best solution for managing sessile oak young and medium-aged stands seems to be a “dynamic”, crop tree silviculture, with the most valuable individuals selected as “potential” final crop trees at the end of thicket stage. These trees should be favoured by subsequent heavy intensity thinning from above, in order to produce timber with as uniform as possible radial increments of 2-3 mm, as requested by veneer and high-quality saw log buyers.

Measuring tree species diversity is necessary to manage forest resources sustainably and to better understand the economic consequences to changes in species diversity due to management. This research aimed at comparing the basal area and trees abundance for evaluating tree species diversity in oriental beech (Fagus orientalis Lipsky) forests (Guilan, Masal, Northern Iran). For this study, compartment 515 was selected, and then data were collected through the random-systematic method with a grid dimension of 150×150 m in an area of 50 ha, and lozenge shape with the sizes of 400; 800; 1,000; 1,200; 1,600; 2,000; 2,500; and 5,000 m2 was established. In total, 160 sampling plots were taken. In each plot, the diameter at breast height (DBH≥7.5 cm) of all trees was measured. Diversity and evenness indices were estimated applying different variables (the basal area and the trees abundance) separately. The results elucidated that the error percentage of Mac Arthur’s N1, Hill’s N2 indices, and Simpson's evenness, was lower using basal area compare to the trees abundance. The result of Camargo, Nee, and Smith-Wilson evenness indices revealed that the error percentage by using the trees abundance was lower than the amount of basal area. We recommend using the basal area for estimating tree species diversity.

Atterberg limits and penetration resistance are the factors that affect the mechanical behavior of soil. In this study, it was investigated the direct and indirect effect of some soil properties such as particle size distribution, moisture and organic matter content, aggregation rate, aggregate stability, and clay activity index on penetration resistance, liquid limit, plastic limit, and plasticity index and revealing the change of all studied properties along with the soil layers. A pasture was selected as the study area and 20 sample points were determined randomly. Penetration resistance (PR) was measured with a penetrologger at these points and soil samples were taken from three different soil layers (0-25, 25-50, and 50-75 cm). The analyses were carried out to determine the soil properties in the laboratory. One-way variance analysis (ANOVA) was used to determine the variation of the soil properties along with the sample layers, and the path analysis was used to determine the direct-indirect effects of the properties affecting the penetration resistance, liquid limit, plastic limit, and plasticity index. The path analysis results showed that clay content directly affected the penetration resistance with the highest coefficient, and organic matter content affected the aggregation rate. The clay content had the highest direct effect, and the organic matter content had the highest indirect effect on the penetration resistance. The highest direct effect coefficient was obtained from organic matter in the plastic limit and liquid limit, while the aggregation rate was in the plasticity index.

Political and economic decision-making processes take into account the rationality criteria of forests such as productivity, profitability, and economy. While these criteria in developed countries in the sense of forestry have positive values, such values of developing countries are fluctuating. In Turkey, only wood-based and non-wood forest products of forests are included in national balance sheets. Therefore, it is thought that the real value of forests could not be calculated. However, calculating the actual values will change all balances. Thus, the discussions on the capacity of forests are moved to a more mathematical ground. The fact that the capacity of the forests is not enough to meet all the needs causes the forest assets to be endangered and therefore requires rationality in using. The concept of rationality is based on rules and obtaining reasonable results, and it has been used frequently in recent studies of game theory modeling initiatives. Effective use of this approach in forest policy and economics will contribute to the development of forests, villagers and the country's economy by obtaining more rational results, and will also be beneficial to eliminate some problems between decision makers and the public. In the last 20 years, the 10-fold increase in forestry-based game theory modeling researches in the world indicates that the game theory approach has begun to be included in decision-making processes aimed at achieving sustainable forestry. As a consequence, the game theory approach seems a new and effective tool that will contribute to the economically and politically rational management of forestry.

The aim of this research was to introduce the forest floor plants species, their life-forms, and describe their geographic distribution in the Asalem Watershed basin (no.7), Western Guilan province (part of Western Hyrcanian) in northern forests of Iran. The Asalem forest is one of the most important and valuable areas of Caspian forest in Iran. The study was conducted on 91 plots of 400 m2 (20 × 20 m) along 19 transects in the basis of a random- systematic sampling design. Inside each main plot, three quadrates (5 × 5 m) on the diagonal line and internal quadrates (1 × 1 m) were chosen, and all of the floor plants collected. The results revealed that there were 306 species, 181 genera and 54 families. The main family was Poaceae with 36 species and 25 genera (12%). Then, the highest number of species belonged to the Asteraceae with 28 species, Fabaceae with 26 species, Lamiaceae with 20 species, Rosaceae with 14 species, Apiaceae and Cyperaceae each including 13 species, Caryophyllaceae with 12 species, Rubiaceae and Orchidaceae each including 11 species. Regarding to the life forms, Hemicryptophytes with 45% (137 species) were the largest group. The chorological analysis indicated that species belonging to the regions of Euro-Siberian were the most significant ecological groups.

For sustainable forest development a stable, functional, and therefore species-rich ecosystem is required to fulfil the diverse functions of forests. Rare tree species contribute substantially to diversity and provided an important habitat function for other species. Further, they have a vital impact on the stability of forest ecosystems and increase their biodiversity. Under climate change, these tree species become more important and should be planted in the forest to divide upcoming risks among different tree species. In the study altogether 906 trees from 19 populations of English yew were sampled evenly along the Bavarian distribution range. Our study based on 13 isoenzyme markers identified substantial genetic variation between the populations. Based on genetic variation within and between studied populations seed stands and gene conservation units (GCU) were proposed. In addition, following our results provenance recommendations were drawn. Selected forest genetic resources (FGR) will be presented in the Bavarian Forest reproductive material (FRM) information system. In addition to dynamic in-situ conservation, an ex-situ conservation of the English yew is sought through long-term seed storage and the establishment of a seed orchard. Thus, the first 19 plus trees have been selected. The number of plus trees should be increased by further selection taking into consideration the balance between female and male English yew trees. All efforts will have a strong impact on the conservation of the FGR of English yew in Bavaria.