EJPAU, 2003, Volume 6, Issue 2
Forestry

Process of seed extraction from the cones is long-lasting and energy-consuming. The state of spruce cone opening can be achieved in the kilns used at present after several hours of drying. Undertaking of an attempt towards improvement of the process calls for learning of the factors influencing its realization. The paper contains the results of investigations on convectional drying of spruce cones of various size, and the proposed mathematical description of the changes in their moisture content in time. It was proved that they could be well represented by a trinomial square of coefficients significantly influenced by the cone volume. However, the time essential for opening the cone dried at temperature 58°C amounted to 6–8 hours, independently of the cone size. The moisture content of open cone amounted to 3–8%.

The study covers juvenile, transient and mature wood of Norway spruce. It was acknowledged that there is a close relation between stages of growth and wood properties. It appears that wood as of material, biological origin has diversified properties from the butt log to the crown. The weakest part of the log is the middle part composed of the juvenile wood. For the purpose of this study differentiation of growth stages was based on the wood density.

The aim of the research was to establish the reasons for the deep, long-term depression in tree ring formation, which took place in the period from 1950-1980 in Douglas firs (Pseudotsuga menziesii Franco) growing in southern Poland. 340 tree rings from 17 trees from the Sudety Mts., the Western Beskidy Mts., Eastern Beskidy Mts. and Roztocze underwent dendrochronological analyses. Results indicate Douglas fir’s high sensitivity to air pollution. Long-term drop in tree-ring widths in the years 1950-1980 was probably caused by industrial emissions. Climatic conditions influenced mainly short-term changes in tree-ring sizes and could not have been the cause of long-term depression. The long-term drop in tree-ring widths varied in terms of intensity depending on particular region. It occurred first and with greatest intensity in western Poland, in the Sudety. In the Bieszczady and Roztocze, it took place later and was less intense. Apart from being smaller, the tree-rings were also chara

Stands of European beech cover around 4.1% of the total forest area in Poland. In the Carpathians the share of European beech amounts to 25.9%. Long intervals between mast seed years in beech force foresters to optimize the seed management. The separation of seeds into various quality classes is usually done with devices working on the basis of physical properties of seeds. The goal of this work was to analyze the critical velocity of beechnuts in order to determine, if the aerodynamic properties of beechnuts can be used as a basis for their separation. The other goal of this work was development of an algorithm of computer-aided image analysis.