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Differences in the intensity of silvicultural treatments, as well as natural tree mort-ality, insect damage and fungal disease can eventually lead to variable stand density even on sites of the same quality. In addition, the bigger the initial stand density,the smaller the crown and trunk volume of single trees. The objective of theresearch was a detailed analysis of the impact of stand density on the total stand volume and value of merchantable timber. The area studied was in Drawno ForestDistrict, north-west Poland, on sites with sandy soil conditions typical for Scots pine (Pinus sylvestris L.). The total volume of merchantable roundwood wasmeasured on 20 sample plots (each covering an area of 0.5 ha) of which 19 were in 82-year-old stands and one in an 87-year-old stand. The stands were divided into three stand density groups (SDG), where the average number of trees growing per group was as follows: 547 (SDG I), 651 (SDG II) and 765 (SDG III). The volume ofa single tree was calculated using diameter (DBH) and height measurement. A qualityclassification of all 6432 tree stems was carried out in accordance with the Polish Standard. Statistical analysis did not indicate that density influenced the total timber volume of the stands studied, which was recorded as an average of 323 m3∙ha-1. However,statistically significant differences in the value of merchantable timber were observed:the highest value of 100 m3 of merchantable timber was recorded in SDG I (€ 5118.87), 6 and 12% higher than in SDGs II and III (€ 4842.09 and € 4565.80, respectively).The results obtained suggest that in the final phase (the last two age classes), pine stands growing in Polish conditions should be maintained at a lower stand density.
Modern forestry management should be based on the principle of sustainability.In order to preserve habitat productivity, the amount of nutrients removed from the environment along with forestry products must be taken into consideration. This study shows the exact concentrations of chemical elements in different tree parts of Scots pine, growing on poor soils in north-western Poland. The observedvalues were compared to the values found in literature. In addition, the relationship between the concentrations of elements and stem diameter or stand density was researched. The highest concentration of chemical elements was observed in the needles (C, N, P, K, Mg, S, Mn, Na, Fe) and the lowest (C, N, P, S, Cu, Na, Ni, Pb, Zn, Fe) in the stem wood. Most of the macronutrients (P, K, Ca, Mg and S) reached optimal values, with the exception of N showing a deficiency, especially in the needles. The relationship between the content of elements and DBH or stand density was rather weak, and in both cases, negative.
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